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How to lock table for reading and writing with php? Here is what I tried without luck.
mysql_query("LOCK TABLES table WRITE;");
mysql_query("LOCK TABLES table READ, WRITE;");
mysql_query("LOCK TABLES table READ WRITE;");
Here is the error I got:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WRITE' at line 1
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A locked table remains locked until you either commit your transaction or roll it back, either entirely or to a savepoint before you locked the table. A lock never prevents other users from querying the table. A query never places a lock on a table. Readers never block writers and writers never block readers.
The following is the syntax that allows us to acquire a table lock explicitly: LOCK TABLES table_name [READ | WRITE];
1. Shared Lock (S): Another transaction that tries to read the same data is permitted to read, but a transaction that tries to update the data will be prevented from doing so until the shared lock is released. Shared lock is also called read lock, used for reading data items only.
The MySQL locks are taken at the same time as those acquired explicitly with the LOCK TABLES statement. If a table is locked explicitly for reading with LOCK TABLES but needs to be locked for writing since it might be modified within a trigger, a write lock might be taken instead of a read lock.
mysql_query("LOCK TABLE table WRITE"); // you might think it's here
mysql_query("LOCK TABLE table READ, table AS t2 WRITE"); // <- but the error is here
mysql_query("LOCK TABLES table READ, table as t2 WRITE"); // <- ...and here.
You can not acquire multiple locks for the same table without aliasing it. Read the manual.
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