/**
* Build a data definition from a pre-existing table. This is used
* to intelligently alter tables that have already been installed.
*
* @param string $table The name of the table to get a data definition for.
* @return array|null
*/
function getDataDefinition($table)
{
// make sure the table exists
if (!$this->tableExists($table)) {
return array();
}
// check if we have a cached version of this table description.
if (expSession::issetTableCache($table)) {
return expSession::getTableCache($table);
}
$res = @mysqli_query($this->connection, "DESCRIBE `" . $this->prefix . "{$table}`");
$dd = array();
for ($i = 0; $i < mysqli_num_rows($res); $i++) {
$fieldObj = mysqli_fetch_object($res);
$field = array();
$field[DB_FIELD_TYPE] = $this->getDDFieldType($fieldObj);
if ($field[DB_FIELD_TYPE] == DB_DEF_STRING) {
$field[DB_FIELD_LEN] = $this->getDDStringLen($fieldObj);
}
$dd[$fieldObj->Field] = $field;
}
// save this table description to cache so we don't need to go the DB next time.
expSession::setTableCache($table, $dd);
$this->query_time('getDataDefinition');
return $dd;
}
