CODEWITHSUNDEEP
phppdolocking
Mansoor
Mansoor

Reputation: 285

pdo::beginTransaction does it lock table?

Can I use this function instead of 'LOCK TABLES' query?

Example:

pdo::beginTransaction(); 

    SELECT id AS last_id FROM t WHERE...
    INSERT INTO t (id,...) VALUES (last_id+1,....)

pdo::commit();

Upvotes: 1

Views: 2925

Answers (1)

DaveRandom
DaveRandom

Reputation: 88697

The answer to this is: it depends. The most important resource to help you understand exactly what it does, what it doesn't do and how it works is here.

For a kick off, it depends whether the underlying driver (MySQL, MSSQL, etc etc) supports transaction functionality at all. If the driver does not support transactions, pdo::beginTransaction(); will fail and return FALSE, and all your queries will be executed immediately. This is not to say that a LOCK TABLES query would fail - it depends whether the underlying database engine supports it.

In fact, in MySQL at least, pdo::beginTransaction() follows the same rules as a START TRANSACTION statement. It does not lock the table immediately, it simply ensures that that the queries that are part of the transaction follow the rules of ACID.

I won't go into full details of exactly which combinations will work and what they will do because they are covered at length in the documents I linked to, and there is no sense in me writing it all out again.

Upvotes: 3

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