MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0
The SCHEMATA_EXTENSIONS
table
(available as of MySQL 8.0.22) augments the
SCHEMATA
table with information about
schema options.
The SCHEMATA_EXTENSIONS
table has
these columns:
CATALOG_NAME
The name of the catalog to which the schema belongs. This
value is always def
.
SCHEMA_NAME
The name of the schema.
OPTIONS
The options for the schema. If the schema is read only, the
value contains READ ONLY=1
. If the schema
is not read only, no READ ONLY
option
appears.
mysql>ALTER SCHEMA mydb READ ONLY = 1;
mysql>SELECT * FROM INFORMATION_SCHEMA.SCHEMATA_EXTENSIONS
WHERE SCHEMA_NAME = 'mydb';
+--------------+-------------+-------------+ | CATALOG_NAME | SCHEMA_NAME | OPTIONS | +--------------+-------------+-------------+ | def | mydb | READ ONLY=1 | +--------------+-------------+-------------+ mysql>ALTER SCHEMA mydb READ ONLY = 0;
mysql>SELECT * FROM INFORMATION_SCHEMA.SCHEMATA_EXTENSIONS
WHERE SCHEMA_NAME = 'mydb';
+--------------+-------------+---------+ | CATALOG_NAME | SCHEMA_NAME | OPTIONS | +--------------+-------------+---------+ | def | mydb | | +--------------+-------------+---------+
SCHEMATA_EXTENSIONS
is a
nonstandard INFORMATION_SCHEMA
table.