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
<?php
// connect to database
$conn=mysqli_connect("localhost","user","password","database");
// check connection
if (mysqli_connect_errno()) {
exit('Connect failed: '. mysqli_connect_error());
}
// sql query
$sql =mysqli_query($conn,"TRUNCATE " . TABLE_NAME);
// Print message
if ($sql === TRUE) {
echo 'data delete successfully';
}
else {
echo 'Error: '. $conn->error;
}
$conn->close();
?>
这是我用来清除一个表的代码片段。只需更改$conn info和TABLE_NAME。
其他回答
我发现这可以删除数据库中的所有表:
mysqldump -uUSERNAME -pPASSWORD --add-drop-table --no-data DATABASENAME | grep ^DROP | mysql -uUSERNAME -pPASSWORD DATABASENAME
如果您受到托管解决方案的限制(不能删除整个数据库),则非常有用。
我修改了它来截断表格。mysqldump没有“——add- trunct -table”,所以我做了:
mysqldump -uUSERNAME -pPASSWORD --add-drop-table --no-data DATABASENAME | grep ^DROP | sed -e 's/DROP TABLE IF EXISTS/TRUNCATE TABLE/g' | mysql -uUSERNAME -pPASSWORD DATABASENAME
对我有用 ——edit,修复最后一个命令的错别字
我不确定,但我认为有一个命令可以使用,你可以复制数据库的模式到新的数据库,一旦你这样做了,你可以删除旧的数据库,这之后,你可以再次复制数据库模式到旧的名称。
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”。
<?php
// connect to database
$conn=mysqli_connect("localhost","user","password","database");
// check connection
if (mysqli_connect_errno()) {
exit('Connect failed: '. mysqli_connect_error());
}
// sql query
$sql =mysqli_query($conn,"TRUNCATE " . TABLE_NAME);
// Print message
if ($sql === TRUE) {
echo 'data delete successfully';
}
else {
echo 'Error: '. $conn->error;
}
$conn->close();
?>
这是我用来清除一个表的代码片段。只需更改$conn info和TABLE_NAME。
mysqldump -u root -p --no-data dbname > schema.sql
mysqldump -u root -p drop dbname
mysqldump -u root -p < schema.sql