How do you retrieve the DEFAULT value of a field?

mikejohnston

I have created a table giving a CHAR field a Default value. I want to pull the field name, type and Default value (if any) and display it. I don't have any issue pulling the name and type, but I can't figure out how to get the defualt value. Any ideas?

mad27

I don't think you can get the default value of a record that has other data in it. I suggest to put a 'dummy' row without any data for the field you're interested in, reading the 'dummy' row which now holds the default data, and afterwards deleting that row.

mikeatrpi

Do what the previous poster said, except do it all in a transaction. In the end, just rollback instead of commit:

chriskl

It would help if you'd tell us what database server you are using.

Chris

mad27

Originally posted by mikeatrpi
Do what the previous poster said, except do it all in a transaction. In the end, just rollback instead of commit:

This is only possible on databases that support transactions. MyISAM (the default table type of MySQL) does not support this. I believe you have to use InnoDB tables for that.
Other databases, like Oracle, do support transactions.

the_Igel

as it is said in comments on http://www.php.net/manual/en/function.mysql-fetch-field.php ,
you can retrieve default value via mysql_fetch_field. When I tried, though, I got no result. I think it's highly version-dependant.

Still you can use mysql_queries "show fields" or "describe table" and fetch the default from returned information.