
Handling Per-Primary Key Auto-Increment Indexes
The goal is to implement an auto-increment mechanism that generates distinct auto-increment indexes for each primary key value.
SQL Engine Support
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MySQL (MyISAM Engine): Supports this functionality through the AUTO_INCREMENT keyword on secondary columns in multi-column indexes.
Alternative Solutions
If the native SQL engine does not support this feature, alternative approaches include:
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Triggers: Emulation using triggers requires table locking to prevent race conditions.
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Database Programming: Create a custom incrementer using a database procedure or function.
Suitable Name
This functionality could be referred to as Partitioned Auto-Incrementing, Scope-Bound Auto-Incrementing, or Per-Category Auto-Incrementing.
Non-SQL Database Support
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MongoDB: Offers support for partitioned auto-incrementing using an options field in its document structure.
Implementation Considerations
- Lock handling: Locking the entire table may be necessary to prevent race conditions when using triggers.
- Transaction behavior: Non-transactional approaches ensure uniqueness but not consecutive values within the same scope.
- Data consistency: Deleted rows may cause gaps in the auto-increment sequence, especially in the case of renumbering.
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