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YZWL/IDEA/sys/create_synonym_db.sql

138 lines
4.5 KiB

create
definer = `mysql.sys`@localhost procedure sys.create_synonym_db(IN in_db_name varchar(64), IN in_synonym varchar(64))
comment '
Description
-----------
Takes a source database name and synonym name, and then creates the
synonym database with views that point to all of the tables within
the source database.
Useful for creating a "ps" synonym for "performance_schema",
or "is" instead of "information_schema", for example.
Parameters
-----------
in_db_name (VARCHAR(64)):
The database name that you would like to create a synonym for.
in_synonym (VARCHAR(64)):
The database synonym name.
Example
-----------
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
+--------------------+
5 rows in set (0.00 sec)
mysql> CALL sys.create_synonym_db(''performance_schema'', ''ps'');
+---------------------------------------+
| summary |
+---------------------------------------+
| Created 74 views in the `ps` database |
+---------------------------------------+
1 row in set (8.57 sec)
Query OK, 0 rows affected (8.57 sec)
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| ps |
| sys |
| test |
+--------------------+
6 rows in set (0.00 sec)
mysql> SHOW FULL TABLES FROM ps;
+------------------------------------------------------+------------+
| Tables_in_ps | Table_type |
+------------------------------------------------------+------------+
| accounts | VIEW |
| cond_instances | VIEW |
| events_stages_current | VIEW |
| events_stages_history | VIEW |
...
'
sql security invoker
modifies sql data
BEGIN
DECLARE v_done bool DEFAULT FALSE;
DECLARE v_db_name_check VARCHAR(64);
DECLARE v_db_err_msg TEXT;
DECLARE v_table VARCHAR(64);
DECLARE v_views_created INT DEFAULT 0;
DECLARE db_doesnt_exist CONDITION FOR SQLSTATE '42000';
DECLARE db_name_exists CONDITION FOR SQLSTATE 'HY000';
DECLARE c_table_names CURSOR FOR
SELECT TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = in_db_name;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET v_done = TRUE;
-- Check if the source database exists
SELECT SCHEMA_NAME INTO v_db_name_check
FROM INFORMATION_SCHEMA.SCHEMATA
WHERE SCHEMA_NAME = in_db_name;
IF v_db_name_check IS NULL THEN
SET v_db_err_msg = CONCAT('Unknown database ', in_db_name);
SIGNAL SQLSTATE 'HY000'
SET MESSAGE_TEXT = v_db_err_msg;
END IF;
-- Check if a database of the synonym name already exists
SELECT SCHEMA_NAME INTO v_db_name_check
FROM INFORMATION_SCHEMA.SCHEMATA
WHERE SCHEMA_NAME = in_synonym;
IF v_db_name_check = in_synonym THEN
SET v_db_err_msg = CONCAT('Can\'t create database ', in_synonym, '; database exists');
SIGNAL SQLSTATE 'HY000'
SET MESSAGE_TEXT = v_db_err_msg;
END IF;
-- All good, create the database and views
SET @create_db_stmt := CONCAT('CREATE DATABASE ', sys.quote_identifier(in_synonym));
PREPARE create_db_stmt FROM @create_db_stmt;
EXECUTE create_db_stmt;
DEALLOCATE PREPARE create_db_stmt;
SET v_done = FALSE;
OPEN c_table_names;
c_table_names: LOOP
FETCH c_table_names INTO v_table;
IF v_done THEN
LEAVE c_table_names;
END IF;
SET @create_view_stmt = CONCAT(
'CREATE SQL SECURITY INVOKER VIEW ',
sys.quote_identifier(in_synonym),
'.',
sys.quote_identifier(v_table),
' AS SELECT * FROM ',
sys.quote_identifier(in_db_name),
'.',
sys.quote_identifier(v_table)
);
PREPARE create_view_stmt FROM @create_view_stmt;
EXECUTE create_view_stmt;
DEALLOCATE PREPARE create_view_stmt;
SET v_views_created = v_views_created + 1;
END LOOP;
CLOSE c_table_names;
SELECT CONCAT(
'Created ', v_views_created, ' view',
IF(v_views_created != 1, 's', ''), ' in the ',
sys.quote_identifier(in_synonym), ' database'
) AS summary;
END;