11.8. Using Data Types from Other Database Engines

To facilitate the use of code written for SQL implementations from other vendors, MySQL maps data types as shown in the following table. These mappings make it easier to import table definitions from other database systems into MySQL.

Other Vendor Type MySQL Type
BOOL TINYINT
BOOLEAN TINYINT
CHARACTER VARYING(M) VARCHAR(M)
FIXED DECIMAL
FLOAT4 FLOAT
FLOAT8 DOUBLE
INT1 TINYINT
INT2 SMALLINT
INT3 MEDIUMINT
INT4 INT
INT8 BIGINT
LONG VARBINARY MEDIUMBLOB
LONG VARCHAR MEDIUMTEXT
LONG MEDIUMTEXT
MIDDLEINT MEDIUMINT
NUMERIC DECIMAL

Data type mapping occurs at table creation time, after which the original type specifications are discarded. If you create a table with types used by other vendors and then issue a DESCRIBE tbl_name statement, MySQL reports the table structure using the equivalent MySQL types. For example:

mysql> CREATE TABLE t (a BOOL, b FLOAT8, c LONG
        VARCHAR, d NUMERIC);Query OK, 0 rows affected (0.00 sec)mysql> DESCRIBE t;+-------+---------------+------+-----+---------+-------+| Field | Type          | Null | Key | Default | Extra |+-------+---------------+------+-----+---------+-------+| a     | tinyint(1)    | YES  |     | NULL    |       || b     | double        | YES  |     | NULL    |       || c     | mediumtext    | YES  |     | NULL    |       || d     | decimal(10,0) | YES  |     | NULL    |       |+-------+---------------+------+-----+---------+-------+4 rows in set (0.01 sec)



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