I'll go over the Rank and Dense_Rank Functions in SQL Servers with examples in this article. In SQL Server, the RANK and DENSE_RANK procedures were introduced. Once more, these two procedures are utilized to return consecutive numbers beginning at 1 in accordance with the ORDER BY clause's ordering of the rows. Before attempting to comprehend how these functions differ from one another, let's first examine these functions in further detail using a few instances.

Note: If there are two records with identical data, both rows will have the same rank.

RANK Function in SQL Server
The following is the syntax for using the RANK function in SQL Server. As you can see, like the Row_Number function, here also the Partition By clause is optional while the Order By Clause is mandatory.

The PARTITION BY clause is basically used to partition the result set into multiple groups. As it is optional, and if you did not specify the PARTITION BY clause, then the RANK function will treat the entire result set as a single partition or group. The ORDER BY clause is required, and this clause is used to define the sequence in which each row is going to assign its RANK i.e. number. If this is not clear at the moment, then don’t worry. We will try to understand this with some examples.

Examples to understand Rank and Dense_Rank function in SQL Server.

We are going to use the following Employees table to understand the RANK and DENSE_RANK functions.

Please use the following SQL Script to create and populate the Employees table with the required test data.
Create Table Employees
(
    Id INT PRIMARY KEY,
    Name VARCHAR(50),
    Department VARCHAR(10),
    Salary INT,
)
Go

Insert Into Employees Values (1, 'James', 'IT', 80000)
Insert Into Employees Values (2, 'Taylor', 'IT', 80000)
Insert Into Employees Values (3, 'Pamela', 'HR', 50000)
Insert Into Employees Values (4, 'Sara', 'HR', 40000)
Insert Into Employees Values (5, 'David', 'IT', 35000)
Insert Into Employees Values (6, 'Smith', 'HR', 65000)
Insert Into Employees Values (7, 'Ben', 'HR', 65000)
Insert Into Employees Values (8, 'Stokes', 'IT', 45000)
Insert Into Employees Values (9, 'Taylor', 'IT', 70000)
Insert Into Employees Values (10, 'John', 'IT', 68000)
Go

RANK Function without PARTITION
Let us see an example of the RANK function in SQL Server without using the PARTITION BY Clause. When we did not specify the PARTITION BY Clause, then the RANK function will treat the entire result set as a single partition and give consecutive numbering starting from 1 except when there is a tie.

The following is an example of the RANK function without using the PARTITION BY clause. Here we use the Order By Clause on the Salary column. So, it will give the rank based on the Salary column.

SELECT Name, Department, Salary,
RANK() OVER (ORDER BY Salary DESC) AS [Rank]
FROM Employees

Once you execute the above query, you will get the following output. As you can see in the below output, there will be no partition, and hence all the rows are assigned with consecutive sequences starting from 1 except when there is a tie i.e. when the salary is 8000 and 65000, it gives the same rank to both the rows.

The Rank function in SQL Server skips the ranking(s) when there is a tie. As you can see in the above output, Ranks 2 and 6 are skipped as there are 2 rows at rank 1 as well as 2 rows at rank 5. The third row gets rank 3 and the 7th row gets rank 7.

RANK Function with PARTITION BY clause in SQL Server

Let us see an example of the RANK function using the PARTITION BY clause in SQL Server. When you specify the PARTITION BY Clause, then the result set is partitioned based on the column that you specify in the PARTITION BY clause. Please have a look at the following image to understand this better. As you can see we have specified Department in the Partition By clause and Salary in the Order By clause.

As in the Employees table, we have two departments (IT and HR). So, the Partition By Clause will divide all the records into two partitions or two groups. One partition is for IT department employees and another partition is for HR department employees. Then in each partition, the data is sorted based on the Salary column. The RANK function then gives an integer sequence number starting from 1 to each record in each partition except when there is a tie. In the case of a tie, it gives the same rank and then skips the ranking.

Now execute the following code and you will get the output as we discussed in the previous image.
SELECT Name, Department, Salary,
               RANK() OVER (
                               PARTITION BY Department
                               ORDER BY Salary DESC) AS [Rank] FROM Employees

So, in short, The RANK function Returns an increasing unique number for each row starting from 1 and for each partition. When there are duplicates, the same rank is assigned to all the duplicate rows, but the next row after the duplicate rows will have the rank it would have been assigned if there had been no duplicates. So the RANK function skips rankings if there are duplicates.

DENSE_RANK Function in SQL Server
The following is the syntax for using the DENSE_RANK function. As you can see, like the RANK function, here also the Partition By clause is optional while the Order By Clause is mandatory.

The PARTITION BY clause is optional and it is used to partition the result set into multiple groups. If you did not specify the PARTITION BY clause, then the DENSE_RANK function will treat the entire result set as a single partition. The ORDER BY clause is mandatory and it is used to define the sequence in which each row is going to assign with their DENSE_RANK i.e. number. Let us understand how to use the DENSE_RANK function in SQL Server with some examples.
DENSE_RANK Function without PARTITION BY clause in SQL Server

Let us see an example of the DENSE_RANK function without using the PARTITION BY Clause. As we already discussed, if we did not specify the PARTITION BY Clause, then the DENSE_RANK function will treat the entire result set as a single partition and give consecutive numbering starting from 1 except when there is a tie.

The following is an example of the DENSE_RANK function without using the PARTITION BY clause. Like the RANK function, here we also apply for the Order By Clause on the Salary column. So, it will give the rank based on the Salary column.

SELECT Name, Department, Salary,
            DENSE_RANK() OVER (ORDER BY Salary DESC) AS [Rank]
FROM Employees

When you execute the above SQL Query, it will give you the following output. As you can see in the output, there will be no partition, and hence all the rows are assigned with consecutive sequences starting from 1 except when there is a tie i.e. when the salary is 8000 and 65000, it gives the same rank to both the rows.

Unlike the Rank function, the DENSE_RANK function will not skip the ranking(s) when there is a tie. As you can see in the above output, we have two rows with rank 1 and the next immediate row rank is 3 and this is the only difference between RANK and DENSE_RANK function in SQL Server.
DENSE_RANK Function with PARTITION BY clause in SQL Server

Let us see an example of the DENSE_RANK function in SQL Server using the PARTITION BY Clause. Like the RANK function, it will also partition the result set based on the column that you specify in the PARTITION BY Clause. In order to understand this better, please have a look at the following diagram. As you can see we have specified the Department column in the Partition By clause and Salary column in the Order By clause.

As we have two departments i.e. IT and HR, so, the Partition By Clause will divide all the data into two partitions. One partition is going to hold the IT department employees while the other partition is going to hold the HR department employees. Then in each partition, the records are sorted based on the Salary column. The DENSE_RANK function is then applied on each record in each partition and provides sequence numbers starting from 1 except when there is a tie. In the case of a tie, it gives the same rank without skipping the ranking.

Now execute the below SQL Script and you should get the output as we discussed in the previous image.

SELECT Name, Department, Salary,
               DENSE_RANK() OVER (
                               PARTITION BY Department
                               ORDER BY Salary DESC) AS [DenseRank]
FROM Employees

What is the difference between Rank and Dense_Rank functions in SQL Server?
As we already discussed the one and only difference is Rank function skips ranking(s) if there is a tie whereas the Dense_Rank will not skip the ranking.

The Real-time examples of RANK and DENSE_RANK Functions in SQL Server:
If you are attending any interview, then one famous question is being asked in almost all interviews i.e. find the nth highest salary. Both the RANK and DENSE_RANK functions can be used to find nth highest salary. However, when to use which function basically depends on what you want to do when there is a tie. Let us understand this with an example.

Suppose, there are 2 employees with the FIRST highest salary, then there might be 2 business cases as follows.
If your business requirement is not to produce any result for the SECOND highest salary then you have to use the RANK function.
If your business requirement is to return the next Salary after the tied rows as the SECOND highest Salary, then you have to use the DENSE_RANK function.

Fetch the 2nd Highest Salary using the RANK function
Since, in our Employees table, we have 2 employees with the FIRST highest salary (80000), the Rank() function will not return any data for the SECOND highest Salary. Please execute the SQL script below and see the output.
-- Fetch the 2nd Hight Salary
WITH EmployeeCTE  AS
(
    SELECT Salary, RANK() OVER (ORDER BY Salary DESC) AS Rank_Salry
    FROM Employees
)

SELECT TOP 1 Salary FROM EmployeeCTE WHERE Rank_Salry = 2

Fetch the 2nd Highest Salary using DENSE_RANK Function
As we have 2 Employees with the FIRST highest salary i.e. 80000, the Dense_Rank() function will return the next Salary after the tied rows as the SECOND highest Salary i.e. 70000. Please execute the following SQL Script and see the output.
-- Fetch the 2nd Hight Salary
WITH EmployeeCTE  AS
(
    SELECT Salary, DENSE_RANK() OVER (ORDER BY Salary DESC) AS DenseRank_Salry
    FROM Employees
)

SELECT TOP 1 Salary FROM EmployeeCTE WHERE DenseRank_Salry = 2

Example to find the Highest Salary Department
You can also use the RANK and DENSE_RANK functions in SQL Server to find the nth highest Salary department-wise. For example, if someone asks you to find the 3rd highest salary of the IT Department, then you can use the DENSE_RANK function as shown below.
WITH EmployeeCTE  AS
(
    SELECT Salary, Department,
           DENSE_RANK() OVER (PARTITION BY Department ORDER BY Salary DESC)
           AS Salary_Rank
    FROM Employees
)

SELECT TOP 1 Salary FROM EmployeeCTE WHERE Salary_Rank = 3
AND Department = 'IT'

To put it briefly, the DENSE_RANK function yields an increasing unique number for each division and row beginning at 1. If there are duplicates, all of the duplicate rows are given the same rank; no levels are skipped. This indicates that the subsequent row in the series will have the next rank after the duplicate rows.

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I will show you how to check disk space utilization in SQL Server in this article, with a particular emphasis on how to find the disk space consumed by different tables. Database administrators must keep an eye on disk space use to guarantee optimal database performance and prevent storage-related problems. Through this approach, you will be able to better plan, optimize, and manage your storage resources by knowing how much disk space each table takes up.

How Can I Check How Much Disk Space Each Table Is Using?
A SQL Server database can be checked for disk space use by table using one of two approaches.

Integrated function located in Reports (SQL Server Management Studio)
We will go over "Disk Usage By Table" in this section, but first, let's take a step-by-step look at the built-in function under reports (the report menu has a lot of reports that we may see). I've downloaded the "NorthWind" database in order to provide an example of disk utilization by table.

The total amount of space allotted to each table in the list will be shown in the report. The "Orders" table takes up the most room in the example below, followed by the "OrderDetails" table, the "Employees" table, and so on.

Using SQL Stored Procedure/Query
If you want to calculate disk space utilization by tables in an SQL Server database using a stored procedure and customize your report, you can do so with a stored procedure. I’ve created one to calculate disk space utilization by tables. Please see the stored procedure below.
CREATE PROCEDURE USP_GetDiskSpaceUsedByTables
AS
BEGIN
    SELECT
        t.name AS TableName,
        s.name AS SchemaName,
        p.rows,
        SUM(a.total_pages) * 8 AS TotalReservedSpaceKB,
        SUM(a.used_pages) * 8 AS UsedSpaceKB,
        (SUM(a.total_pages) - SUM(a.used_pages)) * 8 AS UnusedSpaceKB,
        CAST(ROUND(((SUM(a.total_pages) * 8) / 1024.00), 2) AS NUMERIC(36, 2)) AS TotalReservedSpaceMB,
        CAST(ROUND(((SUM(a.used_pages) * 8) / 1024.00), 2) AS NUMERIC(36, 2)) AS UsedSpaceMB,
        CAST(ROUND(((SUM(a.total_pages) - SUM(a.used_pages)) * 8) / 1024.00, 2) AS NUMERIC(36, 2)) AS UnusedSpaceMB
    FROM
        sys.tables t
    INNER JOIN
        sys.indexes i ON t.object_id = i.object_id
    INNER JOIN
        sys.partitions p ON i.object_id = p.object_id AND i.index_id = p.index_id
    INNER JOIN
        sys.allocation_units a ON p.partition_id = a.container_id
    LEFT OUTER JOIN
        sys.schemas s ON t.schema_id = s.schema_id
    WHERE
        t.name NOT LIKE 'dt%'
        AND t.is_ms_shipped = 0
        AND i.object_id > 255
    GROUP BY
        t.name, s.name, p.rows
    ORDER BY
        TotalReservedSpaceMB DESC, t.name
END

Let's execute this stored procedure and review the results, which are calculated in the same way as the built-in SQL report functionality.

Why Check Disk Space Utilization by Tables in a SQL Server Database?
Here are the key reasons to check disk space utilization by tables in an SQL Server database.

• Performance optimization
• Data management
• Cost management
• Compliance and auditing
• Resource allocation
• Data Archiving
• Post index maintenance

Summary
I've covered efficient ways to keep an eye on and control disk space usage in your SQL Server database in this post. I specifically walk through two methods for monitoring disk space usage at the table level. By employing these techniques, you can obtain important knowledge about how much storage is being used by your database, which will enable you to better effectively schedule your tasks. In your database environment, this proactive management may result in better resource allocation and performance.

Happy reading!

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We will talk about a common problem that arises when we try to install SQL Server 2019 Developer Edition in custom mode in this article. SQL Server is typically installed by default and functions perfectly. Occasionally, nevertheless, we may run into some issues when installing the latest version. Upon installing the SQL Server Developer Edition 2019, I encountered a problem that appears to be related to a PolyBase issue.

Issue
When attempting to log in to SQL Server, an error 18456 was encountered.

Reason
Microsoft SQL Server, Error 18456 is the most common error in SQL server login. There are multiple reasons for this error. At least, we can divide them as two types, the error come from

• SQL Server authentication mode
• Windows Authentication Mode

SQL Server authentication mode
"Login failed for user'sa'. (Microsoft SQL Server, Error 18456)" refers to a specific user's login using the SQL Server authentication mode in the first two situations of our demo. One possible explanation for this scenario is that the SQL server instance is set up for Windows Authentication mode, but you are attempting to use SQL Server Authentication. This is the result of installing SQL Server Basic Mode, which is limited to operating in Windows Authentication mode and not in SQL Server Authentication mode by default.We must change the Windows Authentication Mode to the Mixed Mode in this situation.

The fix for this, I have discussed in my SQL Server installation article SQL Server Installation: 2022 Developer Edition --- Basic, or you may see [ref1], [ref2].

SQL Server authentication mode
For this, the main reason is due to the ID is not in the login list of the Server. We can get the login list by Click Login, under the security folder of the given database:

This can be obtain by SQL Command:
exec master.dbo.xp_logininfo

In different SQL Server:

We can get only one specific group with given parameter:
exec master.dbo.xp_logininfo 'NT SERVICE\Winmgmt'

Get the group members by the optional second parameter 'members':

Fix
If we have the person's ID, or the group name, then we can add it into the login list:

The name must be a valid user ID or AD group name:

Server role: by default --- public

OK

 Choose the specific data tables, and give the appreciate rights => OK

OK => Done

Summary
This login failed with SQL Server authentication is mainly due to lack of the individual ID or group the ID is belong to. Find out it and add it. The error is fixed.

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There is much to look forward to as we eagerly await the introduction of the next edition of SQL Server, which is scheduled for about 2025. Microsoft has been making references to a number of intriguing new features and enhancements that should boost our analytics and database management skills. This is a preview of what's to come:

1. Improved Data Analysis
The enhanced connectivity with Azure Synapse Analytics is one of the most eagerly awaited improvements. This will allow for almost real-time analytics on operational data, which will facilitate the acquisition of knowledge and speedy decision-making based on data.

2. Integration of Object Storage
S3-compatible object storage is anticipated to be supported by the upcoming release. Better data virtualization and direct T-SQL query support for parquet files translate to more opportunities for data management and analysis.

3. Enhanced Accessibility
Features like contained availability groups and disaster recovery replication to an Azure SQL Managed instance are to be expected. More reliable alternatives for preserving high availability and guaranteeing business continuity will be made available by these improvements.

4. Machine Learning and AI
Given AI's increasing significance, improved AI-related functionality will probably be included in the upcoming SQL Server version. In order to improve performance and facilitate the integration of Machine Learning models into your data operations, this may include utilizing GPUs.

5. Enhancements in Performance
As always, performance is the main priority, and the next version is no different. Keep an eye out for improvements to the Maximum Degree of Parallelism (MaxDOP) for query execution and optimizations related to cardinality estimates. These adjustments should lead to faster and more effective searches.

6. Improvements to Security
Security is still of the utmost importance, and the new version will include capabilities to support compliance objectives and data protection. These improvements will guarantee the security of your data and make it easier for you to comply with regulatory standards.

7. Support for Regular Expressions
Lastly, support for regular expressions is one of the most desired features. This will significantly improve the text data manipulation capabilities of SQL Server, facilitating the execution of intricate text searches and transformations.

With these additions, SQL Server's upcoming release should become a very useful tool for developers and data specialists. As the release date approaches, be sure to check back for additional updates!

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Maintaining data availability and integrity is essential to database administration. Preventing data loss requires regularly backing up your database, and understanding how to restore it is crucial for disaster recovery. The procedures for backing up and restoring a SQL database are covered in this article, along with practical examples for common SQL Server setups.

Database Backup's Significance
When you back up your database, you make a backup of your data that you can restore in the event of a software malfunction, hardware failure, or unintentional data loss. Maintaining data consistency and integrity is aided by routine backups.

Backup a SQL Database
Here's how to back up a database in SQL Server.
Using SQL Server Management Studio (SSMS)

• Open SSMS: Connect to your SQL Server instance.
• Select the Database: In the Object Explorer, expand the databases folder, right-click the database you want to back up (e.g., SalesDB), and select Tasks > Back Up.
• Backup Options: In the Backup Database window, specify the following.

1. Backup Type: Choose Full (a complete backup of the entire database).
2. Destination: Add a destination for the backup file (usually a .bak file).

• Execute Backup: Click OK to start the backup process.

Example. Suppose we have a database named SalesDB. The steps would be

• Right-click SalesDB in Object Explorer.
• Select Tasks > Back Up.
• Set the Backup Type to Full.
• Choose the destination path, e.g., C:\Backups\SalesDB.bak.
• Click OK to initiate the backup.

Using T-SQL
You can also use a T-SQL script to back up your database.
BACKUP DATABASE SalesDB
TO DISK = 'C:\Backups\SalesDB.bak'
WITH FORMAT,
     MEDIANAME = 'SQLServerBackups',
     NAME = 'Full Backup of SalesDB';

This script creates a full backup of SalesDB and saves it to the specified path.

Restore a SQL Database
Restoring a database involves copying the data from the backup file back into the SQL Server environment.

• Using SQL Server Management Studio (SSMS)
• Open SSMS: Connect to your SQL Server instance.
• Restore Database: Right-click the Databases folder and select Restore Database.
• Specify Source: In the Restore Database window, choose the source of the backup:

1. Device: Select the backup file location.
2. Database: Choose the database name to restore.

• Restore Options: In the Options page, you can choose to overwrite the existing database and set recovery options.
• Execute Restore: Click OK to start the restoration process.

Example. Suppose we want to restore SalesDB from a backup.

• Right-click Databases in Object Explorer and select Restore Database.
• Under Source, choose Device and select C:\Backups\SalesDB.bak.
• Under Destination, ensure SalesDB is selected.
• In Options, check Overwrite the existing database.
• Click OK to initiate the restore.

Using T-SQL
You can also use a T-SQL script to restore your database:
RESTORE DATABASE SalesDB
FROM DISK = 'C:\Backups\SalesDB.bak'
WITH REPLACE,
     MOVE 'SalesDB_Data' TO 'C:\SQLData\SalesDB.mdf',
     MOVE 'SalesDB_Log' TO 'C:\SQLData\SalesDB.ldf';

This script restores SalesDB from the specified backup file, replacing the existing database, and moves the data and log files to specified locations.

• Best Practices for Backup and Restore
• Regular Backups: Schedule regular backups (daily, weekly) to ensure data is consistently saved.
• Multiple Backup Types: Utilize different backup types (full, differential, and transaction log backups) to balance between backup size and restore time.
• Offsite Storage: Store backups in different physical locations or cloud storage to protect against site-specific disasters.
• Testing: Regularly test your backups by performing restore operations to ensure they are functional and data is intact.
• Security: Encrypt backups and use secure storage locations to prevent unauthorized access.

Conclusion
One of the most important aspects of database administration is backing up and restoring SQL databases. Knowing how to use T-SQL scripts or SQL Server Management Studio (SSMS) will guarantee data availability and integrity. It is possible to protect your data from loss and guarantee prompt recovery when necessary if you adhere to recommended practices for backups and routinely test your restore operations.

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You can create and run SQL statements dynamically at runtime with SQL Server's sophisticated dynamic SQL functionality. When you need to create sophisticated queries based on changing inputs or circumstances, this feature can be very helpful. It does, however, also have a unique set of difficulties and dangers. The goal of this essay is to give readers a thorough grasp of dynamic SQL, including its multiple execution techniques and recommended usage guidelines. We'll also go over when dynamic SQL is appropriate and when it should be avoided in certain instances.

What is Dynamic SQL?
Dynamic SQL refers to SQL code that is generated and executed at runtime rather than being hard-coded in the application. This approach allows for greater flexibility, as the SQL statements can be tailored based on user input, application state, or other runtime conditions. Dynamic SQL is constructed as a string and then executed by the SQL Server.

Methods of Executing Dynamic SQL
There are two ways to execute dynamic SQL in SQL Server, each with its own advantages and considerations. The primary methods are.
EXECUTE (EXEC)
sp_executesql

EXECUTE (EXEC)
The EXECUTE (or EXEC) statement is a straightforward way to execute dynamic SQL. It is simple and easy to use but has certain limitations.
In the below example, the EXEC statement executes the dynamic SQL string stored in the @SQL variable.

Advantages
Simple to use.

• Suitable for straightforward dynamic SQL statements.

Limitations
Limited parameterization can lead to SQL injection vulnerabilities.
Harder to debug and maintain for complex queries.

sp_executesql
The sp_executesql stored procedure is a more robust and secure way to execute dynamic SQL. It allows for parameterized queries, which enhances security and performance.

In the below example, sp_executesql executes a parameterized dynamic SQL statement, providing better security and performance.
--Syntax
sp_executesql
    [ @stmt = ] statement
    [ , { [ @params = ] N'@parameter_name data_type [ ,...n ]' } ]
    [ , { [ @param1 = ] 'value1' [ ,...n ] } ]
DECLARE @SQL NVARCHAR(MAX);
DECLARE @DepartmentID INT = 1;
SET @SQL = N'SELECT * FROM Employees WHERE DepartmentID = @DeptID';
EXEC sp_executesql @SQL, N'@DeptID INT', @DeptID = @DepartmentID;

Advantages

• Supports parameterization, reducing the risk of SQL injection.
• Allows for better query plan reuse, improving performance.
• More readable and maintainable for complex queries.

Limitations

• Slightly more complex to use than EXEC.
• Requires careful handling of parameter data types and lengths.

When to Use Dynamic SQL?
Dynamic SQL is particularly useful in the following scenarios.
Dynamic Table Names or Column Names: When the table name or column names need to be decided at runtime.

DECLARE @TableName NVARCHAR(100) = 'Employees';
DECLARE @SQL NVARCHAR(MAX);
SET @SQL = N'SELECT * FROM ' + QUOTENAME(@TableName);
EXEC sp_executesql @SQL;

Complex Search Conditions: When the search conditions are not known until runtime and can vary significantly.
DECLARE @SQL NVARCHAR(MAX);
DECLARE @SearchCondition NVARCHAR(100) = 'Salary > 50000';
SET @SQL = N'SELECT * FROM Employees WHERE ' + @SearchCondition;
EXEC sp_executesql @SQL;

Metadata Queries: When querying system catalog views or system tables where the structure is not known until runtime.
Data-Driven Logic: When business logic depends on data that is not known until runtime.

When Not to Use Dynamic SQL?
Dynamic SQL should be avoided in the following scenarios.

• Simple Static Queries: When the SQL statements are known and do not change, using static SQL is simpler and more efficient.
• Security Concerns: If not handled properly, dynamic SQL can lead to SQL injection vulnerabilities.
• Performance Issues: Excessive use of dynamic SQL can lead to poor performance due to the lack of query plan reuse.
• Complexity and Maintainability: Dynamic SQL can make the code more complex and harder to maintain.

Best Practices for Using Dynamic SQL
When using dynamic SQL, follow these best practices to ensure security, performance, and maintainability.

• Always use parameterized queries to prevent SQL injection and improve performance.
• Use the QUOTENAME function to safely include object names (e.g., table names, column names) in dynamic SQL.
• Always validate and sanitize input values to prevent SQL injection.
• Minimize the Use of Dynamic SQL, use dynamic SQL only when necessary. For static or known queries, use regular SQL statements.
• Monitor the performance of dynamic SQL statements and optimize them as needed. Use tools like SQL Server Profiler or Extended Events to analyze performance.
• Document and comment on your dynamic SQL code to make it easier to understand and maintain.

Advanced Topics in Dynamic SQL
Handling Output ParametersDynamic SQL can also handle output parameters using sp_executesql.In the below example, the sp_executesql procedure is used to execute a dynamic SQL statement with an output parameter.DECLARE @SQL NVARCHAR(MAX);
DECLARE @TotalCount INT;
SET @SQL = N'SELECT @Count = COUNT(*) FROM Employees WHERE DepartmentID = @DeptID';
EXEC sp_executesql @SQL, N'@DeptID INT, @Count INT OUTPUT', @DeptID = 1, @Count = @TotalCount OUTPUT;
PRINT @TotalCount;Executing Dynamic DDL statementsDynamic SQL can be used to execute dynamic Data Definition Language (DDL) statements, such as creating or altering tables.In the below example, a table is created dynamically using dynamic SQL.DECLARE @SQL NVARCHAR(MAX);
SET @SQL = N'CREATE TABLE DynamicTable (ID INT, Name NVARCHAR(100))';
EXEC sp_executesql @SQL;Using Dynamic SQL in Stored ProceduresDynamic SQL can be embedded within stored procedures to add flexibility to the procedure logic.In the below example, a stored procedure uses dynamic SQL to retrieve employees based on a department ID.CREATE PROCEDURE GetEmployeesByDepartment
    @DepartmentID INT
AS
BEGIN
    DECLARE @SQL NVARCHAR(MAX);
    SET @SQL = N'SELECT * FROM Employees WHERE DepartmentID = @DeptID';
    EXEC sp_executesql @SQL, N'@DeptID INT', @DeptID = @DepartmentID;
END;

Conclusion
With careful usage and adherence to best practices, dynamic SQL can be an invaluable tool in your SQL Server development toolkit, enabling you to create flexible, efficient, and secure database applications. By following best practices such as using parameterized queries, validating input, and optimizing performance, you can harness the power of dynamic SQL while mitigating its risks. Always consider the specific requirements and constraints of your application to determine when dynamic SQL is appropriate and when static SQL might be a better choice.

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Regardless of degree of experience, designing scalable and efficient apps requires knowing how to establish a database in SQL Server. Our intention is to provide you practical guidance and industry best practices so that you may build a capable SQL Server database. These tips are meant to help you succeed whether you're creating a brand-new database or enhancing an existing one. In this post, we'll go over crucial recommended practices to ensure the viability and efficiency of your database architecture.

Reasonable Database Design Is Essential
A well-organized library is similar to a well-planned database. It makes information easier to retrieve, saves time, and lessens irritation. A strong database design is also the cornerstone of an application in the field of software development. Everything is affected by the layout of your database, including how fast your queries run and how easily you can make changes. Robust designs enhance performance, offer scalability as your application grows, and make maintenance simpler.

The Best Techniques for Creating Efficient Databases in SQL Server
Now let's examine some best practices for efficient SQL Server database design.

Recognizing Database Needs
Work with stakeholders to understand their needs before getting into the details. What kind of data must they store? What connections are there between various data entities? Consider entities to be the principal characters in your database tale. Describe their relationships with one another and the characteristics that make up each entity. The base of your database structure is this. Expansion is taken into account in well-designed databases. When designing your database, consider how the data may evolve over time and ensure that it can accommodate new information without requiring a total overhaul.

Principles of Normalization
Normalization is analogous to database cleanup. It results in a more streamlined and effective structure by minimizing redundancy and dependence problems. Acquire knowledge of the various normal forms (1NF, 2NF, 3NF, and above) and utilize them accordingly. Every standard form is built upon the one before it, guaranteeing that your data is arranged methodically. Normalization is important, but don't go overboard with it. Achieving the right balance prevents excessive complexity and maintains your database user-friendly.

Choosing Appropriate Data Types
Data types define the kind of information your database can store. Choosing the right ones ensures accuracy and efficiency in data storage. Learn about the variety of data types available in SQL Server. From integers to decimals, each type serves a specific purpose. Understand their characteristics and use them according to your needs. Efficient data storage and retrieval are key. Consider the size of your data and the operations you'll perform to optimize for both storage space and performance.

Indexing Strategies
Like an index in a book, a database's index will quickly lead you to the information you're looking for. They are essential for query performance optimization. Understand the differences between non-clustered and clustered indexes and use each one wisely. The speed of your database can be significantly increased by effective indexing, but following best practices is essential. To ensure you get the most out of index creation and selection, consider things like selectivity and the type of queries you are using. A responsive and effective database can only be achieved with properly implemented indexes.

Effective Use of Constraints
Database constraints are essential because they act as guardians and preserve data integrity. Relationships between data entities are specifically managed by primary and foreign key constraints. By enforcing validation rules through the use of check constraints, inaccurate or inconsistent data cannot be included. When no value is specified, default constraints automatically assign a default value, which simplifies data entry. Understanding when and how to apply these constraints wisely is essential to mastering their effective use and guaranteeing a solid and error-free database structure.

Stored Procedures and Functions
Stored procedures and functions in SQL Server offer advantages in modularity and security, contributing to a more manageable codebase. You can design effective stored procedures that simplify execution by following performance guidelines. It is essential to comprehend parameters and return types so that you can customize these components to meet your unique needs. Your stored procedures' adaptability and usefulness are increased by this customization, which eventually boosts the efficiency and maintainability of your database-driven apps.

Avoiding Common Pitfalls
Remove redundant and duplicate data as soon as possible to guarantee a tidy and effective database. Strike the correct balance when using indexes to avoid performance problems and needless complexity. Prevent slow performance by optimizing queries and joins for a responsive application. When designing, keep the future in mind and account for expansion and change to prevent costly redesigns down the road. You can create a database that is not only up-to-date but also scalable and future-proof by taking these factors into account.

Performance Considerations
Refine your queries for maximum performance and examine execution plans to get the most out of the database. To simplify code, make use of variables and temporary tables. Use monitoring techniques and tools to steadily improve database performance over time. This proactive strategy guarantees optimal system performance, preserving scalability and responsiveness.

Security Best Practices
Limit user access by using the least privilege principle, and safeguard sensitive data through secure network transmission and encryption. Keep up with best practices and conduct regular security audits to protect your database from potential threats. With regular audits and the most recent security patches, this method guarantees that users have access only when required, that data is secure during transmission, and that your database is actively safeguarded.

Documentation and Maintenance
To ensure smooth database management, create detailed documentation for clarity. To maximize database performance, carry out maintenance procedures regularly, such as statistics updates and index rebuilds. To ensure smooth updates and systematic tracking of changes, apply version control to the database schema. Together, these procedures support an effective and well-maintained database system.

Conclusion
To put it briefly, organizing your SQL Server database is similar to organizing your application's library. It facilitates easy access to information, minimizes frustration, and saves time. We've covered important procedures, such as identifying user needs and putting security measures in place.

Keep in mind that a good database changes to meet your needs. For better efficiency, review and optimize frequently and adjust as necessary. By following these guidelines, you can create databases that are reliable, expandable, and simple to manage.

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A primary key constraint is a key that has one or more columns to help identify each tuple or record in a table individually.

Qualities
Only distinct values should be assigned to the column designated as the primary key; duplicate values are forbidden. The primary key column contains no NULL values. As a result, there is a necessary value in the column holding the primary key. There is only one primary key per table, even if a primary key may contain more than one column.

Adding a new row using an existing primary key is not feasible.

categorized as,

• A single-column, basic primary key.
• Multiple columns make up the composite primary key.

As stated in the Make a Table or Modify a table statement.

A PRIMARY KEY constraint can be used to create the primary key in a table.

It can be created at a couple of levels.

• Column
• Table

SQL Primary Key at Column level
The primary key should be defined at the column level if it only has one column. The primary key "primary_field_name" is created in the table by the following code.

Syntax
Field_name data_type PRIMARY KEY

Example
CREATE TABLE Employee
(
  Id INT NOT NULL PRIMARY KEY,
  [Name] VARCHAR(50) NOT NULL,
  City VARCHAR(20) NOT NULL
)

Let’s verify the primary key with an example.
INSERT INTO Employee
VALUES (1, 'Peter', 'Scott');

Let’s try the execution of the same query again in SQL.

It will throw an exception.

Let’s try with the NULL inserted as the primary key value.
INSERT INTO Employee
VALUES (NULL , 'Peter', 'Scott');

It will throw an error due to null not being allowed in the primary key.

SQL Primary key at Table level
Whenever the primary key contains more than one column, it has to be specified at the table level.

Syntax
CREATE TABLE table_name
(
  field1 data_type,
  field2 data_type,
  ...
  PRIMARY KEY (field1)
)

Example
CREATE TABLE Employee
(
  Id INT NOT NULL,
  [Name] VARCHAR(50) NOT NULL,
  City VARCHAR(20) NOT NULL,
  PRIMARY KEY (Id)
)

Primary Key with Multiple Columns
If you want to add a primary key to more than one column, then that is not possible at the column level; that is possible at the table level.
CREATE TABLE Employee
(
  Id INT NOT NULL,
  [Name] VARCHAR(50) NOT NULL,
  City VARCHAR(20) NOT NULL,
  PRIMARY KEY (Id, [Name])
)

Primary Key with Alter Table
The primary key is typically defined at the time the table is created, but occasionally it might not be created in the table that already exists. However, we can use the Alter Statement to add the primary key.

For a Single Column
Syntax
ALTER TABLE Table_name
ADD PRIMARY KEY (column1);

Example
ALTER TABLE Employee
ADD PRIMARY KEY (Id);

For Multiple Columns
Syntax
ALTER TABLE Table_name
ADD CONSTRAINT primary_key_name PRIMARY KEY (column1, column2);

Example
ALTER TABLE Employee
ADD CONSTRAINT Employee_PK PRIMARY KEY (Id, [Name]);

Remove Primary Key
We can remove the primary key constraint from a table using the DROP statement.

Syntax
ALTER TABLE table_name
DROP CONSTRAINT primary_key_name;

Example
ALTER TABLE Employee
DROP CONSTRAINT Employee_PK;

We learned the new technique and evolved together.
Happy coding!

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Do you make use of SQL Server? Do some teams or DBAs still manage deployments by hand? Are project or financial constraints preventing the incorporation of CI/CD tools? However, there's a chance to use more than one SQL script.

Overview
Running SQL scripts is a standard procedure in database management. But handling several SQL files might make the procedure tiresome and time-consuming. Batch scripts are one of the ways that SQL Server offers for executing SQL scripts. We will examine how to effectively use a batch script to run several SQL files in SQL Server in this article.

Understanding Batch Scripting
Batch scripting is a powerful tool for automating tasks in Windows environments. It allows users to execute a series of commands or scripts in a sequential manner. These scripts are saved with a .bat extension and can be run by simply double-clicking them or through the command line.

Pre-requisite for Batch File
    This script deploys all the .sql files present in a directory or sub-directories in an order.
    NO SPACE in .sql file name.
    NO SPACE in sub-directories.
    To execute .sql in order, add a numeric sequence as follows:
    createtable.sql
    insertdata.sql
    execstoredproc....etc.
    Specify the SERVERNAME, which is mandatory.
    DATABASENAME is optional (Commented-out). In case enabling add (-d%dbname%) after -E at line like (SQLCMD -S%SERVERNAME% -E -d%dbname% -b -i%%G >> :: :: %logfilepath%).
    Specify the SCRIPTLOCATION, which is mandatory.
    The execution log will be captured on the same SCRIPTLOCATION for successful execution and failure.

Steps to Follow

• Copy the below batch script and save it as "ExecuteSQLFiles.bat".
• Update SERVERNAME, SCRIPTLOCATION, and LOGLOCATION accordingly for your needs.

    :: Pre-requisites to follow

    :: This script deploys all the .sql files present in a directory or sub-directories in an order.
    :: NO SPACE in .sql file name.
    :: NO SPACE in sub-directories.
    :: To execute .sql in order add numeric sequence as follows: 1.createtable.sql,
    :: 2.insertdata.sql, 3.execstoredproc....etc.
    :: Specify the SERVERNAME which is mandatory
    :: DATABASENAME is optional (Commented-out). In case enabling add (-d%dbname%) after -E at line like
    :: (SQLCMD -S%SERVERNAME% -E -d%dbname% -b -i%%G >> :: :: %logfilepath%).
    :: Specify the SCRIPTLOCATION which is mandatory.
    :: The execution log will be captured on the same SCRIPTLOCATION for successful execution and failure.

    @echo off
    setlocal enabledelayedexpansion

    set SERVERNAME=LAPTOP-AOVLBDQ4
    ::set DATABASENAME=MyWork
    set SCRIPTLOCATION=C:\Peter\AutoDepSQLFiles\SQL\
    set LOGLOCATION=C:\Peter\AutoDepSQLFiles\Logs\
    set hr=%time:~0,2%

    if "%hr:~0,1%" equ " " set hr=0%hr:~1,1%
    set logfilepath= %LOGLOCATION%\ExecutionLog_%date:~-4,4%%date:~-10,2%%date:~-7,2%_%hr%%time:~3,2%%time:~6,2%.log
    set cmd='dir %SCRIPTLOCATION%\*.sql /b/s'

    FOR /f %%G IN (%cmd%) DO (
    echo ******PROCESSING %%G FILE******
    echo ******PROCESSING %%G FILE****** >> %logfilepath%
    SQLCMD -S%SERVERNAME% -E -b -i%%G >> %logfilepath%
    IF !ERRORLEVEL! NEQ 0 GOTO :OnError
    )
    GOTO :Success

    :OnError
    echo ERROR ERROR ERROR
    echo One\more script(s) failed to execute, terminating bath.
    echo Check output.log file for more details
    EXIT /b

    :Success
    echo ALL the scripts deployed successfully!!
    EXIT /b

Copy the below SQL scripts into separate files in respective folders.
--File Name 1.TableCreation.sql

USE MyWork
GO

CREATE TABLE dbo.Employee (Id INT IDENTITY(1,1), Emp_Name VARCHAR(100))

--File Name 2.InsertData.sql

USE MyWork
GO

INSERT dbo.Employee
SELECT 'Peter'
UNION
SELECT 'Scott'


--File Name 3.AlterTable.sql

USE MyWork
GO

ALTER TABLE dbo.Employee ADD Email VARCHAR(200)

--File Name 4.UpdateTable.sql

USE MyWork
GO

UPDATE dbo.Employee
SET Email = '[email protected]'
WHERE Emp_Name = 'Peter'

UPDATE dbo.Employee
SET Email = '[email protected]'
WHERE Emp_Name = 'Scott'

• Execute the bat file, and upon successful completion, a log file will be generated in the Log directory.
• All SQL scripts within the folder will have been executed.
• If there are any failures, refer to the execution log for details

Folder Structure
Batch File

SQL Files

Verify The Deployment
As a part of this process, we initiated by creating an Employee table with Id and Emp_Name columns in the first file. Subsequently, we inserted two rows in the second file, followed by altering a table to include an Email column in the third script. Finally, in the fourth script, we updated the employee records to include email addresses.

In SQL Server, batch scripting offers a practical means of running numerous SQL files simultaneously. Batch scripts facilitate database management operations, increase productivity, and guarantee consistency in deployment procedures by automating the execution process. Users can efficiently handle their SQL execution demands by creating and running batch scripts by following the instructions provided in this article.

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In the realm of database management, understanding the nuances of data types is crucial for optimizing performance, storage and ensuring data integrity. When it comes to storing textual data, SQL Server offers a variety of data types, two of which are VARCHAR and NVARCHAR. While both are used for storing character data, they have significant differences that impact storage, indexing, and manipulation. In this comprehensive guide, we delve into the intricacies of VARCHAR and NVARCHAR in SQL Server, exploring their features, use cases, and performance implications.

VARCHAR
VARCHAR, short for Variable Character, is a data type used to store non-Unicode string data of variable length in SQL Server. It allocates storage only for the actual length of the data plus two bytes. The maximum storage size for VARCHAR is 8,000 bytes.
NVARCHAR

NVARCHAR, short for National Variable Character, is used to store Unicode string data of variable length. Unlike VARCHAR, NVARCHAR stores Unicode characters, allowing it to support multiple languages and character sets. It also allocates storage only for the actual length of the data plus two bytes. The maximum storage size for NVARCHAR is also 8,000 bytes.

What Sets VARCHAR and NVARCHAR Apart

Encoding of Characters

• VARCHAR uses the underlying operating system's default code page, usually ANSI or ASCII, to store data in the database.
• NVARCHAR uses the UTF-16 encoding technique to store Unicode data in the database. This makes it possible for NVARCHAR to support a large character set from multiple languages.

Size of Storage

• For non-Unicode characters, VARCHAR uses one byte per character.
• For Unicode characters, NVARCHAR takes two bytes each character.
• For the same amount of text data, NVARCHAR takes more storage space than VARCHAR because of the Unicode encoding.

Data Range

• Data in languages like English, Spanish, or French that do not require Unicode support can be stored using VARCHAR.
• When working with multilingual applications or when the data may contain characters from several languages, NVARCHAR is crucial.

Performance-Related Issues

• VARCHAR can provide marginally better performance in terms of storage and retrieval due to the smaller storage size, particularly when working with huge volumes of data.
• NVARCHAR has a performance overhead because of its Unicode encoding and greater storage capacity. Nonetheless, on contemporary systems, this overhead is frequently insignificant, and in most situations, the advantages of Unicode support exceed the performance concerns.

Example 1. Storing English Text
Consider a scenario where you need to store the names of employees in a database table. Since the names are in English and do not require Unicode support, VARCHAR would be the appropriate choice.

CREATE TABLE dbo.Employees (
EmployeeID INT PRIMARY KEY,
FirstName VARCHAR(50),
LastName VARCHAR(50) );

In this example, we define the FirstName and LastName columns as VARCHAR data types with a maximum length of 50 characters each.

Example 2. Storing Multilingual Text
Now, suppose you're working on an international e-commerce platform that caters to customers from various countries, each with its own languages and character sets. In this case, using NVARCHAR would be necessary to support the diversity of languages.
CREATE TABLE dbo.Products (
ProductID INT PRIMARY KEY,
ProductName NVARCHAR(100),
Description NVARCHAR(MAX) );

Here, we define the ProductName and Description columns as NVARCHAR data types. The ProductName column stores the name of the product, while the Description column stores a detailed description. Using NVARCHAR ensures that the database can accommodate text in any language, facilitating a seamless user experience for customers worldwide.

Conclusion
VARCHAR and NVARCHAR are essential data types in SQL Server for storing character data. While VARCHAR is suitable for non-Unicode text and offers slightly better performance in terms of storage and retrieval, NVARCHAR is necessary when dealing with multilingual applications or when Unicode support is required. Understanding the differences between these data types is crucial for designing efficient database schemas and optimizing performance in SQL Server environments. By choosing the appropriate data type based on the nature of the data and the requirements of the application, developers can ensure data integrity, performance, and compatibility across different languages and character sets.

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