10.3.7. Examples of Character Set and Collation Assignment
The following examples show how MySQL determines default
character set and collation values.
Example 1: Table and Column
Definition
CREATE TABLE t1
(
c1 CHAR(10) CHARACTER SET latin1 COLLATE latin1_german1_ci
) DEFAULT CHARACTER SET latin2 COLLATE latin2_bin;
Here we have a column with a latin1
character
set and a latin1_german1_ci
collation. The
definition is explicit, so that's straightforward. Notice that
there is no problem with storing a latin1
column in a latin2
table.
Example 2: Table and Column
Definition
CREATE TABLE t1
(
c1 CHAR(10) CHARACTER SET latin1
) DEFAULT CHARACTER SET latin1 COLLATE latin1_danish_ci;
This time we have a column with a latin1
character set and a default collation. Although it might seem
natural, the default collation is not taken from the table
level. Instead, because the default collation for
latin1
is always
latin1_swedish_ci
, column
c1
has a collation of
latin1_swedish_ci
(not
latin1_danish_ci
).
Example 3: Table and Column
Definition
CREATE TABLE t1
(
c1 CHAR(10)
) DEFAULT CHARACTER SET latin1 COLLATE latin1_danish_ci;
We have a column with a default character set and a default
collation. In this circumstance, MySQL checks the table level to
determine the column character set and collation. Consequently,
the character set for column c1
is
latin1
and its collation is
latin1_danish_ci
.
Example 4: Database, Table, and Column
Definition
CREATE DATABASE d1
DEFAULT CHARACTER SET latin2 COLLATE latin2_czech_ci;
USE d1;
CREATE TABLE t1
(
c1 CHAR(10)
);
We create a column without specifying its character set and
collation. We're also not specifying a character set and a
collation at the table level. In this circumstance, MySQL checks
the database level to determine the table settings, which
thereafter become the column settings.) Consequently, the
character set for column c1
is
latin2
and its collation is
latin2_czech_ci
.