是否存在在一次操作中截断数据库中所有表的查询(命令)?我想知道我是否可以用一个查询做到这一点。
当前回答
To truncate a table, one must drop the foreign key constraints mapped to the columns in this table from other tables (in fact on all tables in the specific DB/Schema). So, all foreign key constraints must be dropped initially followed by table truncation. Optionally, use the optimize table (in mysql, innodb engine esp) to reclaim the used data space/size to OS after data truncation. Once data truncation is carried out, create the same foreign key constraints again on the same table. See below a script that would generate the script to carry out the above operations. 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';
现在,运行Db Truncate。生成SQL脚本
的好处。 1)回收磁盘空间 2)不需要删除并重新创建具有相同结构的DB/Schema
缺点。 1) FK约束应该是表中的名称,约束名称中包含“FK”。
其他回答
SET FOREIGN_KEY_CHECKS = 0;
SELECT @str := CONCAT('TRUNCATE TABLE ', table_schema, '.', table_name, ';')
FROM information_schema.tables
WHERE table_type = 'BASE TABLE'
AND table_schema IN ('db1_name','db2_name');
PREPARE stmt FROM @str;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
SET FOREIGN_KEY_CHECKS = 1;
不。没有单独的命令可以一次截断所有mysql表。您必须创建一个小脚本来逐个截断表。
裁判:http://dev.mysql.com/doc/refman/5.0/en/truncate-table.html
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"
Approval_external_system依赖于approval_request 地址视客户而定 Customer_identification取决于客户 External_id取决于客户 凭证取决于客户 Email_address取决于客户 Approval_request取决于客户 Customer_status取决于客户 Customer_image取决于客户
列出表和行数:
klarsen@Chaos:~$ mysql -Bse "SELECT table_name, table_rows FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'cpm'" | cat -n
1 address 297
2 approval_external_system 0
3 approval_request 0
4 country 189
5 credential 468
6 customer 6776
7 customer_identification 5631
8 customer_image 2
9 customer_status 13639
截断你的表:
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
截断表地址 截断表approval_external_system 截断表approval_request 截断表国家 截断表凭据 截断表客户 截断表customer_identification 截断表customer_image 截断表customer_status
验证它是否有效:
klarsen@Chaos:~$ mysql -Bse "SELECT table_name, table_rows FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'cpm'" | cat -n
1 address 0
2 approval_external_system 0
3 approval_request 0
4 country 0
5 credential 0
6 customer 0
7 customer_identification 0
8 customer_image 0
9 customer_status 0
10 email_address 0
在Windows机器上:
注意:
CPM是数据库名称
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
给@Mathias Bynens的回答补充一点。当我运行这个时,我得到了一个错误,因为外键检查
mysql -Nse 'SHOW TABLES' <database_name> | while read table; do mysql -e "SET FOREIGN_KEY_CHECKS=0; DROP TABLE $table" <database_name>; done
如果数据库中有视图,则返回一个错误。我必须通过drop view <view_name>手动清除视图;
由battousaix的Ans是完美的! 我只是使用了他的答案,并创建了截断数据库表的最终工作命令。
mysql -P 3306 -h YOUR_HOST_HERE -u YOUR_USERNAME_HERE -pYOUR_PASSWORD_HERE -Nse 'show tables' DATABASE_NAME |,同时读取表;-h YOUR_HOST_HERE -u your_username - here -pYOUR_PASSWORD_HERE -e "SET FOREIGN_KEY_CHECKS = 0;截断表$ DATABASE_NAME完成
上面的命令将完美地工作于MySQL服务器。
而且,它也包括在内。
设置foreign_key_checks = 0