A brief introduction to MySQL dialect

Putting aside databases, what is dialect in life? A dialect is the unique language of a certain place. It is a language different from that of other places. Only your small area can understand it. Outside of this place, it is another dialect.

The same is true for database dialects. MySQL is a dialect, Oracle is a dialect, and MSSQL is a dialect. While following the SQL specification, they all have their own extended features.

Take paging as an example. MySQL uses the keyword limit for paging, while Oracle uses ROWNUM. MSSQL may have another paging method.

#mysql
select * from t_user limit 10;
# oracle
select * from t_user t where ROWNUM <10;

For the ORM framework, in order to make indiscriminate calls in the upper ORM layer, such as paging, for users, no matter whether you use MySQL or Oracle at the bottom layer, they use the same interface, but the bottom layer needs to call different DBAPIs according to the different database dialects you use. The user only needs to specify which dialect to use during initialization, and the ORM framework will do the rest for you.

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