Question

I have a mysql database of 100’s of tables. Some columns allow null value, some don’t.
I am inserting data into the table dynamically in php mysqli. I am using the following code to insert any null values:

$value = ($value == "") ? null : $value;

But, the problem with this is I am getting Column 'XXX' cannot be null error. How can I determine if the column supports Null values?

Please help.

Answer 1

You can get all information you need about database structure through the database information_schema, like this one (you want the column IS_NULLABLE):

SELECT COLUMN_NAME, DATA_TYPE, IS_NULLABLE, COLUMN_DEFAULT
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = 'tbl_name'
  AND table_schema = 'db_name'
  AND column_name = 'col_name'

Reference:
http://dev.mysql.com/doc/refman/5.0/en/columns-table.html