/*
 
  code for altering tables (but not indexes)
  
*/  

function logErrors(err, msg) {
  console.log(err.toString()+' '+msg);
}

/*
   takes_length takes type of argument, and returns whether
     type takes a size, like varchar(25)
*/
function takes_length(type) {
	
	switch(type)
	{
		case 'int':			case 'integer':		case 'bigint':
		case 'double precision': case 'float':	case 'double':
		case 'serial':		case 'bigserial':	case 'real':
		case 'smallint':	case 'boolean':		case 'box':
		case 'bytea':
		case 'cidr':		case 'circle':		case 'date':
		case 'inet':		case 'line':		case 'lseg':
		case 'macaddr':		case 'money':		case 'path':
		case 'point':		case 'polygon':		
			return false;
		case 'bit':			case 'bit varying': case 'numeric':
		case 'interval':	case 'decimal':		case 'character varying':
		case 'charvar':		case 'character':	case 'text':
		case 'tsquery':		case 'tsvector':	case 'txid_snapshot':
		case 'uuid':		case 'xml':
			return true;
		default:
			return true;
	}
}

var KEEPSAMEVALUE = '~~ keep same ~~';

function AlterTablePanel(rdbAdmin, databaseManager, sqlPanel, receditPanel)
{
	this.panelId = 'alter-table-panel';
	var tableId = 'alter-table-details',
      maxRowId = 0,
	    mode = 'alter',
	    tableMeta = undefined,
      tableIdentifier = undefined,
	    that = this;
	
	// function to handle error result of query submit
	function errback(err,msg) {
		rdbAdmin.showErrorMessage('<pre>'+err.toString()+': '+msg+'</pre>');
	}
	
	// initialize click handlers
	//
	this.init_handlers = function (app) {
		var $panel = $('#'+this.panelId);
		$('#createNewTableBtn').click(function (ev) {
      ev.stopPropagation();
      app.setLocation('#/createtable');
		});
		// add click handler to edit query
		$('#atable-sql-edit').click(function(ev) {
			var query = $('#alter-table-sql-show').html();
			sqlPanel.showQueryLater(query);
      app.setLocation('#/sqlcommand');
      ev.stopPropagation();
		});
		$('#atable-column-comments').click(function (ev) {
      showCommentsColumn(this);
      ev.stopPropagation();
    });
		$('#atable-column-defaults').click(function (ev) {
      showDefaultsColumn(this);
      ev.stopPropagation();
    });
		$('#alter-table-save').click(function (ev) {
			saveTable();
      ev.stopPropagation();
		});
		$('#alter-table-drop').click(function (ev) {
			dropTable();
      ev.stopPropagation();
		});
		$('#alter-table-add-row').click(function (ev) {
			addRowToTable(this);
      ev.stopPropagation();
		});
		// add live onclick handlers for rows (of varying number)
		// handlers for add and delete row butons
		$(' input[id^="alter-table-del-row_"]',$panel).live('click', function(ev) {
			delRowFromTable(this);
      ev.stopPropagation();
		});
		// handler updates sql display for any change in the data entry
		$panel.bind('change', function(ev) {
			onChange(this);
      ev.stopPropagation();
		});
    $('.edit-sql-btn',$panel).click( function (ev) {
      var queryObj = getQueryString();
      sqlPanel.showQueryLater(queryObj);
      rdbAdmin.loadNewPage('#/sqlcommand');
      ev.stopPropagation();
    });
    $('.lookup-create-link',$panel).click( function (ev) {
      if (!$(this).is('.disabledLink')) {
        var queryObj = getQueryString();
        receditPanel.useRecordLater(queryObj);
        rdbAdmin.loadNewPage('#/browser/insert/'+encodeURIComponent('lookup.queries'));
      }
      ev.stopPropagation();
    });
	};

  function getTableDetls(callback)  {
    function successcb(dtls) {
      tableMeta = dtls;
      callback();
    }
    tableMeta = new TableMeta(tableIdentifier);
    databaseManager.getTableDetails(tableMeta.schemaName, tableMeta.tableName, successcb);
  }

	this.show = function(mod,tableName)
	{
    var $panel = $('#'+that.panelId);
    $panel.hide();
		$('#alter-table-comment').val('');
    rdbAdmin.setHeading('');
		mode = mod;
    tableIdentifier = tableName;
    if (mode === 'alter' && tableIdentifier) {
      getTableDetls(function () {
        if (mode === 'alter') {
          rdbAdmin.setHeading("Alter table: " + tableMeta.qualTableName());
          $('#alter-table-drop').css('display', 'inline');
        }
        else {
          rdbAdmin.setHeading("Create new table");
          $('#alter-table-drop').css('display', 'none');
        }
        buildTable(function () {
          updateSQLDisplay();
          $panel.show();
        });
      });
    }
    else {
      $('#cap-tableName').val('');
      $('#cap-oldTableName').val('');
      $('#alter-table-all-fields').val('');
      $('#alter-table-fdefault').val('');
      $('#alter-table-fcomment').val('');
      clearRowsFromTable($panel);
      addRowToTable($('#atable_th').get(0));
      $panel.show();  
    }
	};
	
	function showCommentsColumn(el) {
		var show = ($(el).attr('checked')) ? "" : "none";
		$('input[id^="alter-table-fcomment_"]').parent().css('display',show);
		$('th[id^="alter-table-fcomment"]').css('display',show);
	}
	
	function showDefaultsColumn(el) {
		var show = ($(el).attr('checked')) ? "" : "none";
		$('input[id^="alter-table-fdefault_"]').parent().css('display',show);
		$('th[id^="alter-table-fdefault"]').css('display',show);
	}
	
	function addRowToTable(domel)
	{
		var $table = $('#'+tableId);
		// find row id
		var newrowIdx = parseInt(maxRowId,10) + 1;
		// var $row = $('#atable_th').next().clone().show();
    var $row = $('*[id^="atable_tr"]').first().clone().show();
		var rowID = $(domel).closest('tr').attr('id');
		if(rowID === 'atable_th') { // if add button in header clicked
			rowID = $('#'+tableId+' tbody tr:last').attr('id');
		}
		// function to add row# to end of id values
		var reg = /(\S+)_(\d*)$/;
		function update_id_unique($el,i) {
			var id = $el.attr('id');
			if (id && id.length && reg.test(id)) { //substr(id.length-1)==='_')
				id = id.replace(reg,'$1_'+i);
				$el.attr('id',id);
			}
		}
		// update all *_ ids with iteration number *_#
		$row.attr('id','atable_tr_'+newrowIdx);
		$row.find('td')
			   .add('select',$row)
			   .add('input',$row)
			   .each(function () {
			update_id_unique($(this),newrowIdx);
		});
    // remove prior values
    $row.find('select',$row)
         .add('input',$row)
         .each(function () {
      $(this).val('');
    });

		// attach new row
		maxRowId = maxRowId + 1;
		// remove 'keep same' option
		var $nratf = $row.find('*[id^="alter-table-ftype_"]');
		if ( $nratf && $nratf.length && $nratf.val() === KEEPSAMEVALUE)  {
			$nratf.find('option:first').remove();
		}
    $('#'+rowID).after($row);
		$table.find('*:input:first').change();
	}
	
	function delRowFromTable(domel) {
		var $table = $('#'+tableId);
		// if this is last row - don't delete
		if ($table.find('tbody tr').length === 1) {
			alert('Table must have at least one row!');
			return false;
		}
		// remove html
		var rowID = $(domel).parents().get(1).id;
		$table.find('#'+rowID).remove();
		$table.find('*:input:first').change();
		return false;
	}
	
  function clearRowsFromTable($panel) {
    var $table = $('#'+tableId,$panel),
        $lastRow, rowID;
    // if this is last row - don't delete
    var rowct = $table.find('tbody tr').length;
    while (rowct > 2) {
      $lastRow = $table.find('tbody tr:last');
      rowID = $lastRow.closest('tr').attr('id');
      $table.find('#'+rowID).remove();
      rowct = $table.find('tbody tr').length;
    }
  }

	function onChange(domel) {
		var $row = $(domel).closest('tr');
		var $typeSelect = $row.find('td:eq(1) select');
		// if selected elem is in row...
		if ( $typeSelect.length ) {
			var idre = /^alter-table-ftype_(\d+)$/;
			var tmpId = $typeSelect.attr('id');
			var id = idre.exec(tmpId)[1];
			// make size visible or not, depending on type
			var lenvis = takes_length($typeSelect.val()) ? 'visible' : 'hidden';
			$row.find('#alter-table-flength_'+id).css('visibility',lenvis);
		}
		updateSQLDisplay();
	}
	
	function updateSQLDisplay() {
		var queryObj = getQueryString();
    var $panel = $('#'+that.panelId);
    if (queryObj.query === '') {
      $('#alter-table-sql-show').html('-- nothing to show');
      $('.edit-sql-btn',$panel).addClass('disabledBtn')
                               .attr('disabled','disabled');
    }
    else {
      $('#alter-table-sql-show').html(queryObj.query);
      $('.edit-sql-btn',$panel).removeClass('disabledBtn')
                               .removeAttr('disabled');
    }
    if ( (! queryObj.query) || queryObj.status==='edit-needed') {
      $('#alter-table-save',$panel).addClass('disabledBtn')
                                   .attr('disabled','disabled');
      $('.lookup-create-link',$panel).addClass('disabledLink');
    }
    else {
      $('#alter-table-save',$panel).removeClass('disabledBtn')
                                   .removeAttr('disabled');
      $('.lookup-create-link',$panel).removeClass('disabledLink');
    }
  }

  function getQueryString() {
    var sql;
		if (mode === 'alter') {
			sql = createAlterQueryString();
		}
		else {
			sql = createCreateQueryString();
    }
    return sql;
	}
	
	function buildTable(callLast) {
		// function to add row# to end of id values
		function make_id_unique($el,i) {
			var id = $el.attr('id');
			if (id && id.length && id.substr(id.length-1)==='_') {
				$el.attr('id',id+i);
			}
		}
    if ( !callLast ) {
      callLast = function() {};
    }
		var $table = $('#'+tableId);

		function build(columnComments,tableComment,tablename) {
			// runs for every table, 'create' and 'alter'
			var $hdr = $table.find('tr:first').clone(true);
			var $colrow = $table.find('tr[id^="atable_tr"]:first').show();
			$table.empty().append($hdr);
			$table.append($colrow.clone().hide());
			//<tr id="atable_th"><th>Column Name</th><th>Type</th><th>Length</th>
			//<th>Options</th><th>NULL</th><th style="display: none;" id="alter_table_fdefault">Default</th>
			//<th style="display: none;" id="alter_table_fcomment">Comment</th>
			//<th><input type="image" title="Add next" src="css/plus.gif" id="alter_table_add_row"/></th>
			for (var i=0;i<tableMeta.fields.length;i+=1) {
				var col = tableMeta.fields[i];
				if (col.maxLength === null) {
					col.maxLength = '';
				}
				var $newRow = $colrow.clone().show();
				// put various values in the new row
				$newRow.find('#alter-table-fpos_').val(col.pos);
				$newRow.find('#alter-table-fname_')
				       .add('#alter-table-foldname_',$newRow)
					     .val(col.columnName);
				$newRow.find('#alter-table-flength_')
					     .add('#alter-table-foldlength_',$newRow).val(col.maxLength);
				$newRow.find('#alter-table-fdefault_')
				       .add('#alter-table-folddefault_',$newRow)
				       .val(col.columnDefault===null ? '' : col.columnDefault);
				$newRow.find('#alter-table-fcomment_')
				       .add('#alter-table-foldcomment_',$newRow)
				       .val(columnComments[i]===null ? '' : columnComments[i]);
				// set checkbox status according to field state - null/not null
				if (col.isNullable) {
					$newRow.find('#alter-table-fisnull_')
					       .add('#alter-table-foldisnull_',$newRow)
						     .attr('checked','checked');
				}
				// set checkbox status according to field state - array
				if (parseInt(col.numDims,10) > 0) {
					$newRow.find('#alter-table-farray_')
					       .add('#alter-table-foldarray_',$newRow)
						     .attr('checked','checked');
				}
        // if mode is create - delete 'keep same' option
				if (mode !== 'alter') {
					var $ftopts = $newRow.find('#alter-table-ftype_ option');
					$($ftopts.get(0)).remove();
				}
				// set field type in select input
				// if there's no such type - select ** keep same ** option
				var $typefnd = $newRow.find('#alter-table-ftype_ option').filter(function(){
					return ($(this).val() === col.dataType);
				});
				if ($typefnd.length) {
					$newRow.find('#alter-table-foldtype_')
					       .add('#alter-table-ftype_',$newRow)
						     .val(col.dataType);
				}
				else { // is_customType
					$newRow.find('#alter-table-foldtype_')
					       .add('#alter-table-ftype_',$newRow)
						     .val(KEEPSAMEVALUE);
				}
				// update all *_ ids with iteration number *_#
				$newRow.find('td')
				  	   .add('select',$newRow)
					     .add('input',$newRow)
					     .each(function () {
					make_id_unique($(this),i);
				});
				make_id_unique($newRow,i);
				$table.append($newRow);
				maxRowId = i;
			}
			// save comments
			$('#atable-column-comments').attr('checked','');
			$('#atable-column-defaults').attr('checked','');
			$('#cap-tableName').add('#cap-oldTableName').val(tablename);
			$('#alter-table-comment').add('#alter-table-oldcomment')
				                       .val(tableComment ? tableComment : '');
			$table.find('*:input:first').change();
		}			
		function buildAlterTable() {
			function withDetails(sT) {
				function withOID(table_oid) {
					var tableCmt = false,
              columnCmts = false,
					    tableName = tableMeta.tableName;
					function buildWhenReady() {
						if ( tableCmt !== false && columnCmts !== false ) {
							// pass column and table comments to build
							build(columnCmts,tableCmt,tableName);
              callLast();
						}
					}
					function withColComments(colcmts) {
						columnCmts = colcmts || [];
						buildWhenReady();
					}
					function withTableComments(tabcmt) {
						tableCmt = tabcmt || '';
						buildWhenReady();
					}
					databaseManager.getColumnComments( table_oid,
                                            tableMeta.fields,
												                    withColComments,
                                            logErrors );
					databaseManager.getTableComment( table_oid, withTableComments );
				}
				tableMeta = sT;
				databaseManager.getTableOID( tableMeta.schemaName,
									                   tableMeta.tableName,
									                   withOID );
			}
			databaseManager.getTableDetails( tableMeta.schemaName,
										                   tableMeta.tableName,
										                   withDetails );
		}
		function buildCreateTable() {
			tableMeta = new TableMeta();
			tableMeta.addColumn(new SQLColumn());
			build([],'','');
		}		
		// get table details
		if (mode==='alter') {
			buildAlterTable();
		}
		else {
			buildCreateTable();
		}
	}
	
	function dropTable() {
		if (!confirm('Are you sure?')) {
			return false;
		}
		function dropcb() {
			tableMeta.tableName = '';
			rdbAdmin.updateTableList();
      rdbAdmin.loadNewPage('#/');
		}
		databaseManager.dropTable(tableMeta.qualTableName(),dropcb);
		return true;
	}

	function createCreateQueryString() 	{
		var $panel = $('#'+that.panelId),
		    queryParts = [],
        status = 'ok';
		function queryStart(tableName) {
			return 'CREATE TABLE '+quoteIdentifier(tableName)+' (';
		}
		function tableComment(tableName,tableCmt) {
			return 'COMMENT ON TABLE '+quoteIdentifier(tableName)+" IS '"+
			       tableCmt+"';";
		}
		function columnComment(tableName,columnName,colComment) {
			return 'COMMENT ON COLUMN '+quoteIdentifier(tableName)+'.'+
				   quoteIdentifier(columnName)+" IS '"+
			       colComment+"';";
		}
		function queryColumn(fname,ftype,flen,farray,fnull,fdefault) {
			var colParts = ['   '];
			colParts.push(fname);
			var typ = ftype;
			if (flen) {
				typ += '('+flen+')';
			}
			if (farray) {
				typ += '[]';
			}
			colParts.push(typ);
			if (fdefault) {
				colParts.push("DEFAULT '~~'".replace('~~',fdefault));
			}
			colParts.push(fnull ? 'NULL' : 'NOT NULL');
			return colParts.join(' ');
		}
		// retrieve elements from form, add to query parts list
		var tablename = $panel.find('#cap-tableName').val();
    if ( !tablename ) {
      tablename = '~tablename~';
      status = 'edit-needed';
    }
		queryParts.push(queryStart(tablename));

		var queryColumns = [],
			  colComments = [];
		$panel.find('tbody tr:visible').each(function (idx) {
			var $trow = $(this);
			if ($trow.attr('id') === 'atable_th') {
				return true; // skip header row
			}
			var fname = $trow.find('input[id^="alter-table-fname_"]').val();
			var ftype = $trow.find('*[id^="alter-table-ftype_"]').val();
			var flen =  $trow.find('*[id^="alter-table-flength_"]:visible').val();
			var farray = $trow.find('*[id^="alter-table-farray_"]:checked').length;
			var fnull = $trow.find('*[id^="alter-table-fisnull_"]:checked').length;
			var fdefault = $trow.find('*[id^="alter-table-fdefault_"]').val();
			var fcomment = $trow.find('*[id^="alter-table-fcomment_"]').val();
			if (! fname) {
        status = 'edit-needed';
        fname = '~col+~'.replace('+',idx);
      }
			queryColumns.push(queryColumn(fname,ftype,flen,farray,fnull,fdefault));
			if (fcomment) {
				colComments.push([tablename,fname,fcomment]);
			}
			return true;
		});
		queryParts.push(queryColumns.join(',\n'));
		//
		queryParts.push(');'); // close statement
		var tablecmt = $panel.find('#alter-table-comment').val();
		if (tablecmt) {
			queryParts.push(tableComment(tablename,tablecmt));
		}
		for (var ccn in colComments) {
			if (colComments.hasOwnProperty(ccn)) {
				var cc = colComments[ccn];
				var tname = cc[0], cname = cc[1], cmt = cc[2];
				queryParts.push(columnComment(tname,cname,cmt));
			}
		}
		var q = queryParts.join('\n');
    return { 'status' : status,
             'query' : q };
	}
		
	function createAlterQueryString() {
		var $panel = $('#'+that.panelId),
		    tablename = $panel.find('#cap-tableName').val(),
		    queryParts = [];
		function tableRename(oldTableName) {
			return 'ALTER TABLE '+quoteIdentifier(oldTableName)+
				   ' RENAME TO '+quoteIdentifier(tablename);
		}
		function columnRename(oldColName,colName) {
			return 'ALTER TABLE '+quoteIdentifier(tablename)+
				   ' RENAME '+quoteIdentifier(oldColName)+
				   ' TO '+quoteIdentifier(colName);
		}
		function newColumn(fname,ftype,flen,farray,fnull,fdefault) {
			var colParts = ['   ADD COLUMN'];
			colParts.push(quoteIdentifier(fname));
			var typ = ftype;
			if (flen) {
				typ += '('+flen+')';
			}
			if (farray) {
				typ += '[]';
			}
			colParts.push(typ);
			if (fdefault) {
				colParts.push("DEFAULT '~~'".replace('~~',fdefault));
			}
			colParts.push(fnull ? 'NULL' : 'NOT NULL');
			return colParts.join(' ');
		}
		function queryStart(tableName) {
			return 'ALTER TABLE '+quoteIdentifier(tableName);
		}
		function tableComment(tableName,tableCmt) {
			return "COMMENT ON TABLE ~tn~ IS '~tc~'"
			       .replace('~tn~',quoteIdentifier(tableName))
				   .replace('~tc~',tableCmt);
		}
		function columnComment(tableName,columnName,colComment) {
			return "COMMENT ON COLUMN ~tn~.~cn~ IS '~tc~'"
			       .replace('~tn~',quoteIdentifier(tableName))
			       .replace('~cn~',quoteIdentifier(columnName))
				   .replace('~tc~',colComment);
		}
		function alterColumnType(fname,ftype,flen,farray) {
			var colParts = ['   ALTER COLUMN'];
			colParts.push(quoteIdentifier(fname));
			colParts.push('TYPE');
			var typ = ftype;
			if (flen) {
				typ += '('+flen+')';
			}
			if (farray) {
				typ += '[]';
			}
			colParts.push(typ);
			return colParts.join(' ');
		}
		function alterColumnNull(fname,fnull) {
			var colParts = ['   ALTER'];
			colParts.push(quoteIdentifier(fname));
			colParts.push(fnull ? 'DROP' : 'SET');
			colParts.push('NOT NULL');
			return colParts.join(' ');
		}
		function alterColumnDefault(fname,fdefault) {
			var colParts = ['   ALTER'];
			colParts.push(quoteIdentifier(fname));
			colParts.push(fdefault
					? "SET DEFAULT '~d~'".replace('~d~',fdefault.replace("'","\\'"))
					: 'DROP DEFAULT' );
			return colParts.join(' ');
		}
		function dropColumn(fname) {
			var colParts = ['   DROP COLUMN'];
			colParts.push(quoteIdentifier(fname));
			return colParts.join(' ');
		}
		// retrieve old tablename from form, if name changed, add
		//  a rename to the queryParts list
		var oldTablename = $panel.find('#cap-oldTableName').val();
		if (oldTablename !== tablename) {
			queryParts.push(tableRename(oldTablename));
		}
		var colRenames = [],
			colComments = [], // tuples of (fieldname, columncomment)
			knownfields = [], // list of fields now in db
		    alterQueryParts = [];
		// iterate over rows of html table, and process each
		//  field/row
		$panel.find('tbody tr:visible').each(function () {
			var $trow = $(this);
			if ($trow.attr('id') === 'atable_th') {
				return true; // skip header row
			}
			// get old and new column names. if different, put a rename
			//   sql clip on colRenames list
			var fname = $trow.find('input[id^="alter-table-fname_"]').val(),
			    foldname = $trow.find('input[id^="alter-table-foldname_"]').val();
			knownfields.push(foldname);
			if (foldname && (foldname !== fname)) {
				colRenames.push(columnRename(foldname,fname));
			}
			// get old and new types. if different put a col change action on
			//  alterQueryParts.
			var ftype = $trow.find('*[id^="alter-table-ftype_"]').val(),
			    foldtype = $trow.find('*[id^="alter-table-foldtype_"]').val(),
			    $flen =  $trow.find('*[id^="alter-table-flength_"]'),
			    flen = ($flen && $flen.css('visibility') === 'visible') ? $flen.val() : '',
			    foldlen =  $trow.find('*[id^="alter-table-foldlength_"]').val(),
			    farray = $trow.find('*[id^="alter-table-farray_"]:checked').val() || 0,
			    foldarray = $trow.find('*[id^="alter-table-foldarray_"]:checked').val() || 0,
			    newForm = alterColumnType(fname,ftype,flen,farray),
      // use new name for both
			oldForm = alterColumnType(fname,foldtype,foldlen,foldarray);
			if (foldname && (newForm !== oldForm)) {
				alterQueryParts.push(newForm); 
			}
			// get old and new null status. if changed, add a col change action
			//  on alterQueryParts
			var fnull = $trow.find('*[id^="alter-table-fisnull_"]:checked').length,
			    foldnull = $trow.find('*[id^="alter-table-foldisnull_"]:checked').length;
			if (foldname && (fnull !== foldnull)) {
				alterQueryParts.push(alterColumnNull(fname,fnull));
			}
			// get old and new default values. if changed, add a col change action
			//   to alterQueryParts
			var fdefault = $trow.find('*[id^="alter-table-fdefault_"]').val(),
			    folddefault = $trow.find('*[id^="alter-table-folddefault_"]').val();
			if (foldname && (fdefault !== folddefault)) {
				alterQueryParts.push(alterColumnDefault(fname,fdefault));
			}
			// get old and new column comments. add col change action if necessary
			var fcomment = $trow.find('*[id^="alter-table-fcomment_"]').val(),
			    foldcomment = $trow.find('*[id^="alter-table-foldcomment_"]').val();
			if (fcomment !== foldcomment) {
				colComments.push(columnComment(tablename,fname,fcomment));
			}
			// handle new field
			if (!foldname) {
				alterQueryParts.push(newColumn(fname,ftype,flen,farray,fnull,fdefault));
			}
			return true;
		});
		// compare orig field list with knownfields, and drop un-kept fields
		for (var o in tableMeta.fields) {
			var ofname = tableMeta.fields[o].columnName;
			if ( $.inArray(ofname,knownfields) === -1 ) {
				alterQueryParts.push(dropColumn(ofname));
			}
		}
		// assemble various lists into one big query
		if (alterQueryParts.length) {
			var aq = [ queryStart(tablename),
				         alterQueryParts.join(',\n') ];
			queryParts.push(aq.join('\n'));
		}			
		queryParts = queryParts.concat(colComments);
		// if table comment change, add sql segment
		var tablecmt = $panel.find('#alter-table-comment').val(),
		    oldtablecmt = $panel.find('#alter-table-oldcomment').val();
		if (tablecmt !== oldtablecmt) {
			queryParts.push(tableComment(tablename,tablecmt));
		}
    if (colRenames.length) {
      queryParts.unshift(colRenames.join(';\n'));
    }
    if (queryParts.length) {
  		queryParts.push(''); // force trailing ';'
    }
		var q = queryParts.join(';\n');
    return { 'status' : 'ok',
             'query' : q };
	}
		
	function saveTable() {
		var $panel = $('#'+that.panelId);
    tableIdentifier = $panel.find('#cap-tableName').val();
		function successcb() {
			rdbAdmin.updateTableList();
      rdbAdmin.loadNewPage('#/table/'+encodeURIComponent(tableIdentifier));
		}
		var sqlObj = getQueryString();
		if ( !sqlObj.query  ) {
			alert('nothing to do!');
			return false;
		} 

		// send query to engine, feed results to callback
		databaseManager.sqlEngine.query( { 'q' : sqlObj.query,
                                       'callback' : successcb,
                                       'errback' : errback } );
		return false;
	}
	
}