Choose a suitable data format


The data type used to manipulate and store data has a significant impact on memory consumption, the processor power needed to manipulate the database — both at the application server and browser (manipulation using JavaScript) level — and on the storage space needed.
Picking the wrong data type:
- wastes memory (e.g. if you store all small data in a column designed to store large amounts of data) - causes performance issues (it will be quicker to search for a number than a character string)

Ideally, you should analyze a representative data sample and use this information to decide the data type and sizing.

For a school, the size of the field in which the number of pupils is stored should be based on a statistical study. This allows you to determine if you can use a TINYINT (1 byte, up to 127) or a SMALLINT (2 bytes, up to 32,726). Whatever the situation, the standard choice of an INT (4 bytes, up to 2,147,483,647) is absurd (but unfortunately a common occurrence found during our audits)
Potential saving: up to 8 times less memory and bandwidth consumed. The CPU usage is also cut by the same amount.

This best practice should only be applied if it is coherent with your project's specifications.
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