How Can SQL Server Sequences Simplify Sequential Identifier Generation?

Implementing Sequences in Microsoft SQL Server

Problem Statement:

Using GUIDs for sequential identifiers can be undesirable due to their complexities and limitations.

Solution:

With the introduction of SEQUENCE objects in SQL Server 2012, developers can now easily generate sequential numeric values independent of any table.

Implementation Details:

Creating a Sequence:

CREATE SEQUENCE Schema.SequenceName
AS int
INCREMENT BY 1 ;

Using a Sequence:

1. Declare an integer variable to store the next value:

   DECLARE @NextID int ;

2. Assign the next value in the sequence to the variable:

   SET @NextID = NEXT VALUE FOR Schema.SequenceName;

3. Use the variable in subsequent operations, such as inserting data:

   INSERT Schema.Orders (OrderID, Name, Qty)
     VALUES (@NextID, 'Rim', 2) ;

Advantages of Sequences:

• Simplicity: Sequences provide a straightforward and reliable way to generate sequential values.
• Data Independence: Sequences are not tied to any specific table, allowing for greater flexibility and reusability.
• Deterministic Ordering: The generated values are always sequential, ensuring predictable ordering of records.
• Customization: The increment value can be customized to meet specific requirements.

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