phpmyadmin/libraries/tbl_indexes.lib.php

<?php
/* vim: set expandtab sw=4 ts=4 sts=4: */
/**
 * function library for handling table indexes
 *
 * @version $Id$
 */

/**
 * Return a list of all index types
 *
 * @access  public
 * @return  array       Index types
 * @author  Garvin Hicking (pma@supergarv.de)
 */
function PMA_get_indextypes()
{
    return array(
        'PRIMARY',
        'INDEX',
        'UNIQUE',
        'FULLTEXT',
    );
}

/**
 * Function to get all index information from a certain table
 *
 * @uses    PMA_DBI_fetch_result()
 * @uses    PMA_backquote()
 * @param   string  $tbl_name   Table name to ftech indexes from
 * @param   string  $err_url_0  Error URL
 *
 * @access  public
 * @return  array       Index keys
 */
function PMA_get_indexes($tbl_name, $err_url_0 = '')
{
    return PMA_DBI_fetch_result('SHOW KEYS FROM ' . PMA_backquote($tbl_name));
}

/**
 * Function to check over array of indexes and look for common problems
 *
 * @uses    $GLOBALS['strIndexesSeemEqual']
 * @uses    PMA_get_indexes()
 * @uses    is_string()
 * @uses    is_array()
 * @uses    count()
 * @uses    array_pop()
 * @uses    reset()
 * @uses    current()
 * @access  public
 * @param   mixed       array of indexes from PMA_get_indexes()
 *                      or name of table
 * @return  string      Output HTML
 */
function PMA_check_indexes($idx_collection)
{
    if (is_string($idx_collection)) {
        $idx_collection = PMA_get_indexes($idx_collection);
    }

    // count($idx_collection) < 2:
    //   there is no need to check if there less than two indexes
    if (! is_array($idx_collection) || count($idx_collection) < 2) {
        return false;
    }

    $indexes = array();
    foreach ($idx_collection as $index_field) {
        $indexes[$index_field['Key_name']][$index_field['Column_name']]
            = $index_field;
    }

    $output  = '';

    // remove last index from stack and ...
    while ($while_index = array_pop($indexes)) {
        // ... compare with every remaining index in stack
        foreach ($indexes as $each_index_name => $each_index) {
            if (count($while_index) !== count($each_index)) {
                // number of fields are not equal
                continue;
            }

            // compare some key elements of every column in this two indexes
            foreach ($each_index as $col_name => $each_index_column) {
                if (! isset($while_index[$col_name])
                 // the position
                 || $while_index[$col_name]['Seq_in_index'] !== $each_index_column['Seq_in_index']
                 // the order, ASC or DESC
                 || $while_index[$col_name]['Collation']    !== $each_index_column['Collation']
                 // the length
                 || $while_index[$col_name]['Sub_part']     !== $each_index_column['Sub_part']
                 // BTREE or HASH
                 || $while_index[$col_name]['Index_type']   !== $each_index_column['Index_type']) {
                    continue 2;
                }
            }

            // did not find any difference
            // so it makes no sense to have this two equal indexes

            // use first column from index to fetch index name
            reset($while_index);
            $first_column = current($while_index);

            $message = PMA_Message::warning('strIndexesSeemEqual');
            $message->addParam($each_index_name);
            $message->addParam($first_column['Key_name']);
            $output .= $message->getDisplay();

            // there is no need to check any further indexes if we have already
            // found that this one has a duplicate
            continue 2;
        }
    }

    if ($output) {
        $output = '<tr><td colspan=7">' . $output . '</td></tr>';
    }

    return $output;
}

/**
 * Loop array of returned index keys and extract key information to
 * seperate arrays. Those arrays are passed by reference.
 *
 * @param   array       Referenced Array of indexes
 * @param   array       Referenced return array
 * @param   array       Referenced return array
 *
 * @access  public
 * @return  boolean     void
 * @author  Garvin Hicking (pma@supergarv.de)
 */
function PMA_extract_indexes(&$ret_keys, &$indexes_info, &$indexes_data)
{
    if (! is_array($ret_keys)) {
        return false;
    }

    $prev_index   = '';
    foreach ($ret_keys as $row) {
        if ($row['Key_name'] != $prev_index){
            $indexes[]  = $row['Key_name'];
            $prev_index = $row['Key_name'];
        }

        $indexes_info[$row['Key_name']]['Sequences'][]     = $row['Seq_in_index'];
        $indexes_info[$row['Key_name']]['Non_unique']      = $row['Non_unique'];

        if (isset($row['Cardinality'])) {
            $indexes_info[$row['Key_name']]['Cardinality'] = $row['Cardinality'];
        }

        //    I don't know what does following column mean....
        //    $indexes_info[$row['Key_name']]['Packed']          = $row['Packed'];
        $indexes_info[$row['Key_name']]['Comment']         = (isset($row['Comment']))
                                                           ? $row['Comment']
                                                           : '';
        $indexes_info[$row['Key_name']]['Index_type']      = (isset($row['Index_type']))
                                                           ? $row['Index_type']
                                                           : '';

        $indexes_data[$row['Key_name']][$row['Seq_in_index']]['Column_name']  = $row['Column_name'];
        if (isset($row['Sub_part'])) {
            $indexes_data[$row['Key_name']][$row['Seq_in_index']]['Sub_part'] = $row['Sub_part'];
        }
    } // end while

    return true;
}

?>