11.7. 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:
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)
