From f4fb1db458fab52d0493ead52c9ea7e01206eaa7 Mon Sep 17 00:00:00 2001 From: Joël Cox Date: Sun, 9 Oct 2011 18:39:39 +0200 Subject: Moved tutorial to new user guide directory. --- user_guide/database/transactions.html | 200 ---------------------------------- 1 file changed, 200 deletions(-) delete mode 100644 user_guide/database/transactions.html (limited to 'user_guide/database/transactions.html') diff --git a/user_guide/database/transactions.html b/user_guide/database/transactions.html deleted file mode 100644 index 1a25f1657..000000000 --- a/user_guide/database/transactions.html +++ /dev/null @@ -1,200 +0,0 @@ - - - - - -Transactions : CodeIgniter User Guide - - - - - - - - - - - - - - - - - - - - - -
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CodeIgniter User Guide Version 2.0.3

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Transactions

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CodeIgniter's database abstraction allows you to use transactions with databases that support transaction-safe table types. In MySQL, you'll need -to be running InnoDB or BDB table types rather than the more common MyISAM. Most other database platforms support transactions natively.

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If you are not familiar with -transactions we recommend you find a good online resource to learn about them for your particular database. The information below assumes you -have a basic understanding of transactions. -

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CodeIgniter's Approach to Transactions

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CodeIgniter utilizes an approach to transactions that is very similar to the process used by the popular database class ADODB. We've chosen that approach -because it greatly simplifies the process of running transactions. In most cases all that is required are two lines of code.

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Traditionally, transactions have required a fair amount of work to implement since they demand that you to keep track of your queries -and determine whether to commit or rollback based on the success or failure of your queries. This is particularly cumbersome with -nested queries. In contrast, -we've implemented a smart transaction system that does all this for you automatically (you can also manage your transactions manually if you choose to, -but there's really no benefit).

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Running Transactions

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To run your queries using transactions you will use the $this->db->trans_start() and $this->db->trans_complete() functions as follows:

- - -$this->db->trans_start();
-$this->db->query('AN SQL QUERY...');
-$this->db->query('ANOTHER QUERY...');
-$this->db->query('AND YET ANOTHER QUERY...');
-$this->db->trans_complete(); - - -

You can run as many queries as you want between the start/complete functions and they will all be committed or rolled back based on success or failure -of any given query.

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Strict Mode

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By default CodeIgniter runs all transactions in Strict Mode. When strict mode is enabled, if you are running multiple groups of -transactions, if one group fails all groups will be rolled back. If strict mode is disabled, each group is treated independently, meaning -a failure of one group will not affect any others.

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Strict Mode can be disabled as follows:

- -$this->db->trans_strict(FALSE); - - -

Managing Errors

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If you have error reporting enabled in your config/database.php file you'll see a standard error message if the commit was unsuccessful. If debugging is turned off, you can -manage your own errors like this:

- - -$this->db->trans_start();
-$this->db->query('AN SQL QUERY...');
-$this->db->query('ANOTHER QUERY...');
-$this->db->trans_complete();
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-if ($this->db->trans_status() === FALSE)
-{
-    // generate an error... or use the log_message() function to log your error
-} - - - -

Enabling Transactions

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Transactions are enabled automatically the moment you use $this->db->trans_start(). If you would like to disable transactions you -can do so using $this->db->trans_off():

- - -$this->db->trans_off()

- -$this->db->trans_start();
-$this->db->query('AN SQL QUERY...');
-$this->db->trans_complete(); - - -

When transactions are disabled, your queries will be auto-commited, just as they are when running queries without transactions.

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Test Mode

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You can optionally put the transaction system into "test mode", which will cause your queries to be rolled back -- even if the queries produce a valid result. -To use test mode simply set the first parameter in the $this->db->trans_start() function to TRUE:

- - -$this->db->trans_start(TRUE); // Query will be rolled back
-$this->db->query('AN SQL QUERY...');
-$this->db->trans_complete(); - - - -

Running Transactions Manually

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If you would like to run transactions manually you can do so as follows:

- - -$this->db->trans_begin();

- -$this->db->query('AN SQL QUERY...');
-$this->db->query('ANOTHER QUERY...');
-$this->db->query('AND YET ANOTHER QUERY...');
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- -if ($this->db->trans_status() === FALSE)
-{
-    $this->db->trans_rollback();
-}
-else
-{
-    $this->db->trans_commit();
-}
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Note: Make sure to use $this->db->trans_begin() when running manual transactions, NOT -$this->db->trans_start().

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