mahara-contributors team mailing list archive

[Robert Lyon <robertl@xxxxxxxxxxxxxxx>]

Public bug reported:

When upgrading we use a field_exists() check to see if a table has a
certain column or not which is fine there as upgrade chunks are a one-
time execution run when users are all logged out.

However we have begun to use field_exists() within other parts of the
code and so this can get called on every page load by multiple users at
once. This requires fetching the ddl.lib file and setting ul an XMLDB
table object and an XMLDB field object which has overhead.

Instead we should just query the database directly and ask it if the
table has the column or not


So instead of doing:

require_once('ddl.php');
$table = new XMLDBTable('tablename');
$field = new XMLDBField('fieldname');
if (field_exists($table, $field)) {
    ...
}

We could just do:

if (column_exists('tablename', 'fieldname')) {
    ...
}

** Affects: mahara
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1827445

Title:
  Improve efficiency when checking if a table field exists

Status in Mahara:
  New

Bug description:
  When upgrading we use a field_exists() check to see if a table has a
  certain column or not which is fine there as upgrade chunks are a one-
  time execution run when users are all logged out.

  However we have begun to use field_exists() within other parts of the
  code and so this can get called on every page load by multiple users
  at once. This requires fetching the ddl.lib file and setting ul an
  XMLDB table object and an XMLDB field object which has overhead.

  Instead we should just query the database directly and ask it if the
  table has the column or not

  
  So instead of doing:

  require_once('ddl.php');
  $table = new XMLDBTable('tablename');
  $field = new XMLDBField('fieldname');
  if (field_exists($table, $field)) {
      ...
  }

  We could just do:

  if (column_exists('tablename', 'fieldname')) {
      ...
  }

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