In SQL Server databases, there are three important functions used to retrieve values associated with auto-increment fields: IDENTITY, SCOPE_IDENTITY(), and IDENT_CURRENT(). Although they serve a similar purpose, these functions have distinct characteristics and use cases. This article aims to explore the differences between them and provide a clear understanding of their individual functionalities.

1. IDENTITY

The IDENTITY attribute is used to define an auto-increment field within a table. For instance, if a table includes an auto-increment field named “ID,” the IDENTITY attribute specifies this property. The IDENTITY attribute automatically increments the value of the field with each new record added to the table. Typically, the data type of an IDENTITY column is INT or BIGINT.

2. SCOPE_IDENTITY()

The SCOPE_IDENTITY() function returns the last auto-increment value generated by an INSERT statement. It operates within the scope of the current execution context within the affected table. In simpler terms, SCOPE_IDENTITY() will only return the auto-increment value generated by the most recent INSERT operation.

Consider the following example:

INSERT INTO MyTable (Name) VALUES ('John');
SELECT SCOPE_IDENTITY();

In the above code snippet, after the INSERT operation creates a new record in the MyTable table, the SCOPE_IDENTITY() function will return the auto-increment value associated with that specific record.

3. IDENT_CURRENT()

The IDENT_CURRENT() function retrieves the current value of an auto-increment field for a specified table. It is particularly useful when you need to obtain the auto-increment value for a specific table.

For instance:

SELECT IDENT_CURRENT('MyTable');

In the given example, the IDENT_CURRENT() function will return the current auto-increment value of the MyTable table.

Differences

Now let’s summarize the differences between these three functions:

• IDENTITY is an attribute that defines an auto-increment field, while SCOPE_IDENTITY() and IDENT_CURRENT() are functions.
• SCOPE_IDENTITY() returns the most recent auto-increment value generated by an INSERT operation, whereas IDENT_CURRENT() retrieves the current auto-increment value for a specific table.
• SCOPE_IDENTITY() operates within the scope of the current execution context, while IDENT_CURRENT() focuses on a specific table.

In conclusion, IDENTITY, SCOPE_IDENTITY(), and IDENT_CURRENT() are crucial components when working with auto-increment fields in SQL Server databases. While IDENTITY defines the attribute, SCOPE_IDENTITY() retrieves the value within the execution context, and IDENT_CURRENT() allows you to obtain the current auto-increment value for a specified table. Understanding the distinctions between these functions is essential for efficiently managing and retrieving auto-incremented values in SQL Server.

I hope you find this article helpful. Happy coding!