Appendix J: Using List and Search screens

SEARCH screens are used to modify or refine the selection criteria used by LIST screens.

• Screens of type LIST 1 are invoked from the menu bar and do not (usually) have any context passed in the $where string. This behaviour may be altered by specifying values for either of the Selection fields which are described in Appendix D.
• Screens of type LIST 2 are activated from the navigation bar and have context passed down in the $where string from the parent screen.

Within each LIST screen you may see the following buttons:

• SEARCH (in the navigation bar) - this will activate the SEARCH screen associated with the current database table
• PREVIOUS SEARCH (in the navigation bar) - this will cause the script's $search variable to be reloaded with the previous search criteria for this database table, and fresh data will be retrieved from the database using the combined contents of the $where, $search, $pageno and $orderby variables.
• RESET (in the action bar) - this will clear the contents of the script's $search, $pageno and $orderby variables and read fresh data from the database using the contents of the $where variable.

Within LIST screens there may also be any of the following options which will affect how the data is retrieved from the database and displayed:

• Within the navigation bar there may be some 'show NN' hyperlinks which will cause the number of rows in each display page to be altered. Fresh data will be retrieved from the database using the new setting.
• Within the column headings each column heading may be shown as a hyperlink which, if pressed, will cause that column name to be loaded into the $orderby variable and fresh data to be retrieved using that column name in the ORDER BY clause of the sql SELECT statement. A symbol will then appear next to the column name to indicate that the data was sorted on that column. The sequence will toggle between 'ascending' and 'descending' when any of these hyperlinks is pressed, and the symbol will change accordingly. Note that the sort is not limited to the data within the current screen - it will cause a fresh set of data to be retrieved from the database which may cause any or all of the current rows to disappear completely from the display.

When a SEARCH screen is activated anything passed down in the $where string will be shown in the screen as read-only and will not be able to be amended. Any previous search criteria used for this database table will be shown and will be able to be amended. Within this screen you may see the following buttons:

• SUBMIT - will use any data entered in this screen to construct the contents of the $search string. Instead of using the format

  fieldname='value'
  

  which requires an exact match the format

  fieldname LIKE 'value'
  

  will be used instead. This allows for the wildcard character '%' to be used anywhere within a string field. The $search string will then be inserted in the session data for the previous script which will then be reactivated using the header() function. When the script runs it will combine the contents of any $where and $search strings before reading fresh data from the database.
• CLEAR - will clear any current selection criteria in the $search variable, but will leave the $where variable intact.
• CANCEL - will return to the parent screen without changing the contents of the $search variable.