Difference Between IDENTITY vs SEQUENCE
IIDENTITY and SEQUENCE are used to generate series numbers in SQL Server, but they’ve unique attributes and utilization statements. Here are the primary differences:
|
Feature |
IDENTITY |
SEQUENCE |
|---|---|---|
|
Syntax |
Typically used in SQL Server, Sybase, and Microsoft Access. |
Commonly used in various databases such as PostgreSQL, Oracle, and IBM Db2. |
|
Auto-increment |
Automatically generates unique values when a new row is inserted into a table. |
Generates unique values when explicitly requested in a query or as a default value. |
|
Generation |
Generated values are sequential integers starting from a defined seed value. |
Values generated can be integers, decimal numbers, or other data types. |
|
Control |
Limited control over the generation process, primarily defining the initial seed value and increment value. |
More control over the generation process, including setting the start value, increment, and cache size. |
|
Portability |
Less portable as it’s specific to certain database systems. |
More portable across different databases. |
|
Usage |
Commonly used for primary key columns. |
Commonly used for generating unique keys in various contexts, not just primary keys. |
|
Performance |
Generally fast for simple cases, as the database engine manages the values. |
Offers better performance when generating many values, especially in high-concurrency scenarios. |
Difference Between Sequence and Identity in SQL Server
In SQL Server International, there are fundamental methods for producing collection numbers: IDENTITY and SEQUENCE. These gear are priceless for growing unique columns in a database, however, additionally, they have different packages.
- IDENTITY is a column-degree asset that has been a part of SQL Server for some time and is to be had in all variations. It generates a series of values on the desk level, perfect for storing specific keys in a specific table.
- SEQUENCE, however, is a recent addition, brought in SQL Server 2012. It is a function that permits sequential sharing of numbers throughout tables, imparting more flexibility and freedom than any specific table.
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