CREATE PROCEDURE truncate_all_tables()
BEGIN
-- Declare local variables
DECLARE done BOOLEAN DEFAULT 0;
DECLARE cmd VARCHAR(2000);
-- Declare the cursor
DECLARE cmds CURSOR
FOR
SELECT CONCAT('TRUNCATE TABLE ', TABLE_NAME) FROM INFORMATION_SCHEMA.TABLES;
-- Declare continue handler
DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET done=1;
-- Open the cursor
OPEN cmds;
-- Loop through all rows
REPEAT
-- Get order number
FETCH cmds INTO cmd;
-- Execute the command
PREPARE stmt FROM cmd;
EXECUTE stmt;
DROP PREPARE stmt;
-- End of loop
UNTIL done END REPEAT;
-- Close the cursor
CLOSE cmds;
END;
SELECT CONCAT('ALTER TABLE ',TABLE_SCHEMA,'.',TABLE_NAME,' DROP FOREIGN KEY ',CONSTRAINT_NAME,';') FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE CONSTRAINT_TYPE='FOREIGN KEY' AND TABLE_SCHEMA='<TABLE SCHEMA>'
UNION
SELECT CONCAT('TRUNCATE TABLE ',TABLE_SCHEMA,'.',TABLE_NAME,';') FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA='<TABLE SCHEMA>' AND TABLE_TYPE='BASE TABLE'
UNION
SELECT CONCAT('OPTIMIZE TABLE ',TABLE_SCHEMA,'.',TABLE_NAME,';') FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA='<TABLE SCHEMA>' AND TABLE_TYPE='BASE TABLE'
UNION
SELECT CONCAT('ALTER TABLE ',TABLE_SCHEMA,'.',TABLE_NAME,' ADD CONSTRAINT ',CONSTRAINT_NAME,' FOREIGN KEY(',COLUMN_NAME,')',' REFERENCES ',REFERENCED_TABLE_NAME,'(',REFERENCED_COLUMN_NAME,');') FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE CONSTRAINT_NAME LIKE 'FK%' AND TABLE_SCHEMA='<TABLE SCHEMA>'
INTO OUTFILE "C:/DB Truncate.sql" LINES TERMINATED BY '\n';
Now, run the Db Truncate.sql script generated
Benefits.
1) Reclaim disk space
2) Not needed to drop and recreate the DB/Schema with the same structure
Drawbacks.
1) FK constraints should be names in the table with the name containing 'FK' in the constraint name.
mysql> select group_concat('truncate',' ',table_name,';') from information_schema.tables where table_schema="db_name" into outfile '/tmp/a.txt';
mysql> /tmp/a.txt;
溶液2)
- Export only structure of a db
- drop the database
- import the .sql of structure
——编辑----
earlier in solution 1, i had mentioned concat() instead of group_concat() which would have not returned the desired result
SELECT CONCAT('TRUNCATE TABLE ',table_schema,'.',TABLE_NAME, ';')
FROM INFORMATION_SCHEMA.TABLES WHERE table_schema IN ('dbSchemaName1','dbSchemaName2');
SELECT Concat('TRUNCATE TABLE ',table_schema,'.',TABLE_NAME, ';')
FROM INFORMATION_SCHEMA.TABLES where table_schema in (db1,db2)
INTO OUTFILE '/path/to/file.sql';
现在使用this来使用这个查询
mysql -u username -p </path/to/file.sql
如果你得到这样的错误
ERROR 1701 (42000) at line 3: Cannot truncate a table referenced in a foreign key constraint
TB=$( mysql -Bse "show tables from DATABASE" );
for i in ${TB};
do echo "Truncating table ${i}";
mysql -e "set foreign_key_checks=0; set unique_checks=0;truncate table DATABASE.${i}; set foreign_key_checks=1; set unique_checks=1";
sleep 1;
done
--
大卫,
感谢您花时间格式化代码,但这是它应该如何应用。
库尔特
在UNIX或Linux机器上:
确保您处于bash shell中。从命令行运行这些命令,如下所示。
注意:
我将凭据存储在~/.my.cnf文件中,因此不需要在命令行上提供凭据。
注意:
CPM是数据库名称
我只展示了来自每个命令的结果的一小部分示例。
找到你的外键约束:
klarsen@Chaos:~$ mysql -Bse "select concat(table_name, ' depends on ', referenced_table_name)
from information_schema.referential_constraints
where constraint_schema = 'cpm'
order by referenced_table_name"
klarsen@Chaos:~$ TB=$( mysql -Bse "show tables from cpm" ); for i in ${TB}; do echo "Truncating table ${i}"; mysql -e "set foreign_key_checks=0; set unique_checks=0;truncate table cpm.${i}; set foreign_key_checks=1; set unique_checks=1"; sleep 1; done
C:\>for /F "tokens=*" %a IN ('mysql -Bse "show tables" cpm') do mysql -e "set foreign_key_checks=0; set unique_checks=0; truncate table %a; foreign_key_checks=1; set unique_checks=1" cpm
SELECT GROUP_CONCAT(Concat('TRUNCATE TABLE ',table_schema,'.',TABLE_NAME) SEPARATOR ';') FROM INFORMATION_SCHEMA.TABLES where table_schema in ('my_db');
DROP PROCEDURE IF EXISTS trunctables;
DELIMITER ;;
CREATE PROCEDURE trunctables(theDb varchar(64))
BEGIN
declare tname varchar(64);
declare tcursor CURSOR FOR
SELECT table_name FROM information_schema.tables WHERE table_type <> 'VIEW' AND table_schema = theDb;
SET FOREIGN_KEY_CHECKS = 0;
OPEN tcursor;
l1: LOOP
FETCH tcursor INTO tname;
if tname = NULL then leave l1; end if;
set @sql = CONCAT('truncate `', theDB, '`.`', tname, '`');
PREPARE stmt from @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
END LOOP l1;
CLOSE tcursor;
SET FOREIGN_KEY_CHECKS = 1;
END ;;
DELIMITER ;
SELECT Concat('TRUNCATE TABLE ',table_schema,'.',TABLE_NAME, ';')
FROM INFORMATION_SCHEMA.TABLES where table_schema in ('databasename1','databasename2');
如果不能删除或更新父行:外键约束失败
如果存在外键指向您试图删除/截断的表的表,就会发生这种情况。
在截断表之前,你需要做的是:
SET FOREIGN_KEY_CHECKS=0;
截断您的表并将其更改回
SET FOREIGN_KEY_CHECKS=1;
用户这个PHP代码
$truncate = mysql_query("SELECT Concat('TRUNCATE TABLE ',table_schema,'.',TABLE_NAME, ';') as tables_query FROM INFORMATION_SCHEMA.TABLES where table_schema in ('databasename')");
while($truncateRow=mysql_fetch_assoc($truncate)){
mysql_query($truncateRow['tables_query']);
}
?>
mysql --defaults-extra-file=.temp.my.cnf -Nse 'show tables' <db_name_goes_here> | while read table; do mysql --defaults-extra-file=.temp.my.cnf -e "truncate table $table" <db_name_goes_here>; done
2.B删除所有表(完全删除)
mysql --defaults-extra-file=.temp.my.cnf -Nse 'show tables' <db_name_goes_here> | while read table; do mysql --defaults-extra-file=.temp.my.cnf -e "drop table $table" <db_name_goes_here>; done