WeBWorK::DB::Schema - schema superclass (to hold documentation)
FIXME: write synopsis
FIXME: write description
Several of the tables used in the WeBWorK database have records that are identified by the values of a set of fields, rather than by the value of a single field. Because of this, when identifying a record (in calls to the list, exists, get, and delete methods), one must specify a list of values rather than a single value. This is represented in the documentation for these methods by the expression @keyparts. The values in @keyparts correspond to the fields returned by the KEYFIELDS method of the table's record class. If an element of @keyparts is undefined, then the corresponding field is not used in the match. Some methods require all elements of @keyparts to be defined. This is noted below.
A "record key", as in the list method, is a reference to a list containing values which correspond to the the fields returned by the KEYFIELDS method of the table's record class.
Creates a schema interface for $table, using the driver interface provided by $driver and using the record class named in $record. If the $driver does not support the driver style needed by the schema, an exception is thrown. $params contains extra information needed by the schema and is schema dependent. $db is provided so that schemas can query other schemas.
Returns the number of records matching @keyparts is found in the table.
Returns a list containing the key of each record in the table that matches the values in @keyparts. Elements of @keyparts may be undefined.
Returns a boolean value representing whether one or more records that match the values in @keyparts exist in the table. Elements of @keyparts may be undefined.
Attempts to add $Record to the table. $Record must be an instance of the table's record class. Returns true on success and false on failure (for example, if the database couldn't be contacted). If a record with the same key exists, an exception is thrown.
Attempts to retrieve the record matching @keyparts from the table. Returns an instance of the table's record class if there is a match. Returns undef if no record matches. All elements of @keyparts must be defined.
Returns a list of records matching the keyparts refered to in each element of @keypartsRef. Each element of the returned list will contain either a record object (if there was a match) or the value undef (if there was no match). All elements of @keyparts must be defined.
Attempts to replace the record in the table that matches the key of $Record. Returns true on success and false on failure (for example, if the database couldn't be contacted). If no such record exists, an exception is thrown.
Attempts to delete the record or records in the table that match @keyparts. Returns true if the record(s) was successfully deleted or did not exist, and false if deletion failed. Elements of @keyparts may be undefined.