"Preparing" a SQL statement

[Anon]

I'm using ODBC and the PHP manuals talks about "preparing" a SQL statment before execution. What does this mean?

-Sonny

[Anon]

I'm not sure, but in ASP/VB there are specific functions used to "prepare" SQL statements. I haven't seen any similar functions in PHP, so I don't know what you're refering to in the manual.

Basically, "preparing" a query means writing a query, but leaving room for the actual data. It's useful for when you need to execute many similar SQL queries - like when you're inserting lots of similar data into a table.

In PHP, I've gotten along by writing the query as a string and using the sprintf function to insert the data. For instance:

<?php

$query_format = '
INSERT INTO my_table
(field1, field2, field3)
VALUES
('%s', 'some_constant_value', 4458823)
';

// some looping construct to do this multiple times:

$query = sprintf($query_format, $field1_value);

mysql_query($query);

?>

-Keegan

[Anon]

I haven't seen any similar functions in PHP,

You're right about the concept, but what's not to see? They're right there in the manual:

&nbsp;&nbsp;&nbsp;&nbsp;odbc_prepare()
&nbsp;&nbsp;&nbsp;&nbsp;odbc_execute()

and, for queries that are going to be executed only once in their current form:

&nbsp;&nbsp;&nbsp;&nbsp;odbc_exec()

which combines both steps into a single function.

[Anon]

I think this is just referring to the odbc statements. Using mysql functions, you dont really have to do this prepare/exec stuff.

[Anon]

In the original question, it was quite clear the writer was talking about ODBC. Some of the other dbms' may also support prepare/execute, but as you say MySQL (and also PostgreSQL) do not.