<?php
/* Classes for database schema.
 *
 * Written by: Chris Studholme
 * Copyright:  GPL (http://www.fsf.org/copyleft/gpl.html)
 * $Id: db_schema.php,v 1.1 2003/12/23 06:07:15 cstudhol Exp $
 */

class db_field {
  var $name;    // field name
  var $type;    // associative array of types (one per db type)
  
  function db_field($name,$type) {
    $this->name = $name;
    if (is_array($type))
      $this->type = $type;
    else
      $this->type = array($type);
  }
  
  function get_type() {
    global $db_type;
    if ($this->type[$db_type])
      return $this->type[$db_type];
    return $this->type[0];
  }
}

class db_table {
  var $name;    // table name
  var $fields;  // array of fields
  var $pkey;    // array primary key fields
  var $index;   // array of other fields to index
  
  function db_table($name,$pkey,$index,$fields) {
    $this->name = $name;
    $this->fields = $fields;
    $this->pkey = $pkey;
    $this->index = $index;
  }
  
  function find_field($aname) {
    for ($i=0; $i<count($this->fields); ++$i) {
      $field=$this->fields[$i];
      if (strcasecmp($field->name,$aname)==0)
	return $field;
    }
    return false;
  }
  
  function create_query() {
    $result = "CREATE TABLE ".$this->name." (";
    for ($i=0; $i<count($this->fields); ++$i) {
      $field=$this->fields[$i];
      $result .= $field->name." ".$field->get_type().", ";
    }	
    $result .= "PRIMARY KEY (".$this->pkey[0];
    for ($i=1; $i<count($this->pkey); ++$i)
      $result .= ",".$this->pkey[$i];
    $result .= "));";
    return $result;
  }
  
  function index_queries() {
    $result=array();
    for ($i=0; $i<count($this->index); ++$i)
      $result[] = "CREATE INDEX ".$this->name."_index_".$this->index[$i].
	" ON ".$this->name." (".$this->index[$i].");";
    return $result;
  }
  
  function add_field_query($field) {
    return "ALTER TABLE ".$this->name.
      " ADD COLUMN ".$field->name." ".$field->get_type().";";
  }
}

?>