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In MySQL, Temporary Table and Memory Table are two different table types, and they have some important differences and uses.
1. Temporary table
Temporary Table is a table used to store temporary data. They only exist during the life cycle of the current session or connection and are automatically deleted when the session ends.
Temporary tables can be created using the CREATE TEMPORARY TABLE statement.
Temporary tables can be stored on disk or in memory, depending on the configuration of MySQL and the storage engine.
Temporary tables are suitable for situations where intermediate results or temporary data need to be stored during a session, avoiding the need to store temporary data in the actual table.
2. Memory table
Memory Table is a table stored in memory. The data is completely stored in memory and the reading and writing speed is very fast.
You can use the ENGINE=MEMORY parameter to create a memory table, or you can use the CREATE TABLE statement and specify the storage engine as MEMORY.
Memory tables are suitable for scenarios that require fast read and write operations, but it should be noted that the data in the memory table will be lost when the MySQL service is restarted because the data is stored in memory.
3.Difference
The main difference is storage and lifecycle:
- Storage: The storage location of temporary tables can be disk or memory, while the data of memory tables is stored in memory.
- Life cycle: The life cycle of the temporary table is limited to the session or connection, and is automatically deleted when the session ends; while the data of the memory table will be lost when the MySQL service is restarted.
4. Summary
You need to choose whether to use temporary tables or in-memory tables based on your business needs. If you need to store data temporarily during a session and ensure that the data is not persisted, you can use temporary tables. If you need high-speed read and write operations, but can accept data loss when the service is restarted, you can consider using a memory table.