CODEWITHSUNDEEP
javasqlpostgresqljdbc
sumit
sumit

Reputation: 3780

Using batchExecute and execute methods on a single statement object in JDBC

I came across an old piece of code which looks like below

Statement stmt = connection.createStatement();
stmt.addBatch(insertQuery);
stmt.addBatch(insertQuery);
stmt.addBatch(insertQuery);
stmt.addBatch(insertQuery);

//there is some data which needs to be deleted before inserting the new data. 
stmt.execute(deleteQuery);
stmt.executeBatch();

Here we are batching up a few query and before executing the batch this code is executing some other delete query and then executing the batch.

Is it legal to do this?

Will the above code work as expected that it will first execute the delete query and then the batch update?

Upvotes: 1

Views: 335

Answers (1)

Mark Rotteveel
Mark Rotteveel

Reputation: 109124

The JDBC specification (version 4.3) says:

The behavior of the methods executeQuery, executeUpdate, and execute is implementation-defined when a statement’s batch is non-empty.

In other words, the behaviour is not specified and depends on the driver implementation, this means it should not be relied on.

A quick (but not thorough) scan of the pgjdbc sources seems to indicate that the PostgreSQL driver indeed allows you to first add statements to the batch, execute a single statement, and then execute the batch.

But in the code shown, I'd suggest to simply first execute the delete query, and only then populate and execute the batch. That order would be a lot simpler to read for people unfamiliar with the code.

Upvotes: 1

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