Monday, May 21, 2012

KirSQLite - Flex AIR Database Manager: Part 20

In this tutorial we will improve our "Add column" function.

Last time we created a function that uses the "ALTER TABLE" SQL command to create a new table. This, however, is not the perfect solution, since there are numerous disadvantages in using this method. When we use "ALTER TABLE", we cannot use the "PRIMARY KEY", "AUTOINCREMENT" or "UNIQUE" clauses - their respective items in the form become useless.

There is a way to bypass this. We can rewrite the whole table from scratch, and just add this column next to the other ones when creating the table. Of course, before rewriting the table, we'll have to store its values in a temporary backup table, then delete the existing one and only then create a new table with new columns, followed by adding all the values from the backup database. Even then we have to watch out for errors - if something goes wrong, we might lose the whole table. So we'll need to keep this backup table until the table is completed, and if there is an error - rename the backup table to the initial table name to restore all the data.

This is pretty hacky, but it's the only way to do it right. There's also no other way to delete or edit columns, so we'll be using this method again in the future. For now, let's get the "Add column" function working properly.

Find the addColumn() function. We'll now heavily edit this function.

First of all, set the emphasized property of the "Update selected" button to false. Then declare a variable that stores the name of the current table:

col_b_update.emphasized = false;
var prevTableName:String = tableTree.selectedItem.@label;

Then goes the if... statement. Here, we'll add a few lines to load the schema in order to get the string of all columns in the table along with their parameters (just like we did in columnSelect()):

if (col_name.text != "" && col_data.textInput.text != "" && (col_null.selected || col_default.text != "")) {
connection.loadSchema(SQLTableSchema, tableTree.selectedItem.@label, tableTree.selectedItem.@databaseName);
var schema:SQLSchemaResult = connection.getSchemaResult();
var fullSQL:String = schema.tables[0].sql;
// extract the text inside the ( )
fullSQL = fullSQL.substring( fullSQL.indexOf("(") + 1 , fullSQL.lastIndexOf(")") );

Then we create the sqlText variable, but this time we use CREATE TABLE instead of ALTER TABLE. The code following that line remains unchanged:

var sqlText:String = "CREATE TABLE " + selectedDatabase + "." + tableTree.selectedItem.@label + " (";
sqlText += fullSQL + ", ";
// add the new column
sqlText += col_name.text + " " + col_data.textInput.text + " ";
if (col_key.selected) sqlText += "PRIMARY KEY ";
if (col_key.selected && col_conflict.selectedIndex > 0) sqlText += "ON CONFLICT " + col_conflict.selectedLabel + " ";
if (col_key.selected && col_auto.selected) sqlText += "AUTOINCREMENT ";
if (!col_null.selected) sqlText += "NOT NULL ";
if (!col_null.selected && col_conflict.selectedIndex > 0) sqlText += "ON CONFLICT " + col_conflict.selectedLabel + " ";
if (col_unique.selected) sqlText += "UNIQUE ";
if (col_unique.selected && col_conflict.selectedIndex > 0) sqlText += "ON CONFLICT " + col_conflict.selectedLabel + " ";
if (col_default.text != "") {
sqlText += "DEFAULT ";
if (isNaN(Number(col_default.text))) sqlText += '"' + col_default.text + '"';
if (!isNaN(Number(col_default.text))) sqlText += col_default.text;
}
sqlText += ");";
lastStatement(sqlText);

After that we need to create a backup table. In order to do that, we need to know what name the backup table should have. It will be created in the same database as the initial table, but we must make sure it has a unique name. We set the name to "backup" and then check if there already is a table like that. If there is, add "0" to the end of the table name and repeat.

// Create backup
var backupName:String = "backup";
while (!tableIsUnique(backupName)) {
backupName += "0";
}

I created this function outside of addColumn() to be able to check if a table is unique:

private function tableIsUnique(name:String):Boolean {
var r:Boolean = true;
for (var i:int = 0; i < dbData..tb.length(); i++) {
if (dbData..tb[i].@label == name) {
r = false;
break;
}
}
return r;
}

Now, after we know the name of the backup table, we create it using CREATE TABLE. Use the fullSQL variable's value to create the same columns as in the initial table:

var bstat:SQLStatement = new SQLStatement();
bstat.sqlConnection = connection;
bstat.text = "CREATE TABLE " + selectedDatabase + "." + backupName + " (" + fullSQL + ");";
bstat.execute();

Then we copy all the existing data from the table to the backup table using an INSERT INTO SQL command:

// Copy data to backup
var cstat:SQLStatement = new SQLStatement();
cstat.sqlConnection = connection;
cstat.text = "INSERT INTO " + selectedDatabase + "." + backupName + " SELECT * FROM " + selectedDatabase + "." + tableTree.selectedItem.@label;
cstat.execute();

Now we can remove the initial table:

// Delete initial table
var dstat:SQLStatement = new SQLStatement();
dstat.sqlConnection = connection;
dstat.text = "DROP TABLE " + selectedDatabase + "." + tableTree.selectedItem.@label;
dstat.execute();

And finally execute the statement with sqlText query - the one that creates a new table with the new columns:

// Create new table
var stat:SQLStatement = new SQLStatement();
stat.sqlConnection = connection;
stat.text = sqlText;
stat.execute( -1, new Responder(newColumnSuccess, newColumnError));

In newColumnSuccess(), we insert the values from backup database into the new database, and then delete the backup.

function newColumnSuccess(evt:SQLResult):void {
// Insert previous values
var istat:SQLStatement = new SQLStatement();
istat.sqlConnection = connection;
istat.text = "INSERT INTO " + selectedDatabase + "." + prevTableName + " (" + columnNames() + ") SELECT " + columnNames() + " FROM " + selectedDatabase + "." + backupName;
istat.execute();
// Delete backup
var bdstat:SQLStatement = new SQLStatement();
bdstat.sqlConnection = connection;
bdstat.text = "DROP TABLE " + selectedDatabase + "." + backupName;
bdstat.execute();
tableSelect();
}

You can see I used a method called columnNames() to list all the columns. It is a simple function that returns a string consisting of column names separated with a comma:

private function columnNames():String {
var r:String = "";
for (var i:int = 0; i < columnData.length; i++) {
r += columnData[i].name;
if (i < columnData.length - 1) r += ", ";
}
return r;
}

In the newColumnError() function, we warn the user of the error, and then restore the initial table by renaming the backup table to the initial name. We can rename a table using ALTER TABLE command:

function newColumnError(evt:SQLError):void {
Alert.show("ERROR: " + evt.details + "\n\nRestoring the database using backup...", "Error");
// Restore table
var rstat:SQLStatement = new SQLStatement();
rstat.sqlConnection = connection;
rstat.text = "ALTER TABLE " + selectedDatabase + "." + backupName + " RENAME TO " + prevTableName
rstat.execute();
tableSelect();
}

Phew! We're done. Full function:

private function addColumn():void {
col_b_update.emphasized = false;
var prevTableName:String = tableTree.selectedItem.@label;
if (col_name.text != "" && col_data.textInput.text != "" && (col_null.selected || col_default.text != "")) {
connection.loadSchema(SQLTableSchema, tableTree.selectedItem.@label, tableTree.selectedItem.@databaseName);
var schema:SQLSchemaResult = connection.getSchemaResult();
var fullSQL:String = schema.tables[0].sql;
// extract the text inside the ( )
fullSQL = fullSQL.substring( fullSQL.indexOf("(") + 1 , fullSQL.lastIndexOf(")") );
var sqlText:String = "CREATE TABLE " + selectedDatabase + "." + tableTree.selectedItem.@label + " (";
sqlText += fullSQL + ", ";
// add the new column
sqlText += col_name.text + " " + col_data.textInput.text + " ";
if (col_key.selected) sqlText += "PRIMARY KEY ";
if (col_key.selected && col_conflict.selectedIndex > 0) sqlText += "ON CONFLICT " + col_conflict.selectedLabel + " ";
if (col_key.selected && col_auto.selected) sqlText += "AUTOINCREMENT ";
if (!col_null.selected) sqlText += "NOT NULL ";
if (!col_null.selected && col_conflict.selectedIndex > 0) sqlText += "ON CONFLICT " + col_conflict.selectedLabel + " ";
if (col_unique.selected) sqlText += "UNIQUE ";
if (col_unique.selected && col_conflict.selectedIndex > 0) sqlText += "ON CONFLICT " + col_conflict.selectedLabel + " ";
if (col_default.text != "") {
sqlText += "DEFAULT ";
if (isNaN(Number(col_default.text))) sqlText += '"' + col_default.text + '"';
if (!isNaN(Number(col_default.text))) sqlText += col_default.text;
}
sqlText += ");";
lastStatement(sqlText);

// Create backup
var backupName:String = "backup";
while (!tableIsUnique(backupName)) {
backupName += "0";
}
var bstat:SQLStatement = new SQLStatement();
bstat.sqlConnection = connection;
bstat.text = "CREATE TABLE " + selectedDatabase + "." + backupName + " (" + fullSQL + ");";
bstat.execute();

// Copy data to backup
var cstat:SQLStatement = new SQLStatement();
cstat.sqlConnection = connection;
cstat.text = "INSERT INTO " + selectedDatabase + "." + backupName + " SELECT * FROM " + selectedDatabase + "." + tableTree.selectedItem.@label;
cstat.execute();

// Delete initial table
var dstat:SQLStatement = new SQLStatement();
dstat.sqlConnection = connection;
dstat.text = "DROP TABLE " + selectedDatabase + "." + tableTree.selectedItem.@label;
dstat.execute();

// Create new table
var stat:SQLStatement = new SQLStatement();
stat.sqlConnection = connection;
stat.text = sqlText;
stat.execute( -1, new Responder(newColumnSuccess, newColumnError));
}else {
Alert.show("Please fill all the required fields!", "Error");
}
function newColumnSuccess(evt:SQLResult):void {
// Insert previous values
var istat:SQLStatement = new SQLStatement();
istat.sqlConnection = connection;
istat.text = "INSERT INTO " + selectedDatabase + "." + prevTableName + " (" + columnNames() + ") SELECT " + columnNames() + " FROM " + selectedDatabase + "." + backupName;
istat.execute();
// Delete backup
var bdstat:SQLStatement = new SQLStatement();
bdstat.sqlConnection = connection;
bdstat.text = "DROP TABLE " + selectedDatabase + "." + backupName;
bdstat.execute();
tableSelect();
}
function newColumnError(evt:SQLError):void {
Alert.show("ERROR: " + evt.details + "\n\nRestoring the database using backup...", "Error");
// Restore table
var rstat:SQLStatement = new SQLStatement();
rstat.sqlConnection = connection;
rstat.text = "ALTER TABLE " + selectedDatabase + "." + backupName + " RENAME TO " + prevTableName
rstat.execute();
tableSelect();
}
}

Full code:

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
                       xmlns:s="library://ns.adobe.com/flex/spark"
                       xmlns:mx="library://ns.adobe.com/flex/mx" showStatusBar="false">
   
<s:menu>
<mx:FlexNativeMenu dataProvider="{windowMenu}" showRoot="false" labelField="@label" keyEquivalentField="@key" itemClick="menuSelect(event);" />
</s:menu>

<fx:Declarations>
<fx:XML id="windowMenu">
<root>
<menuitem label="Database">
<menuitem id="newdb" label="New" key="n" controlKey="true" />
<menuitem id="opendb" label="Open" key="o" controlKey="true" />
<menuitem id="savedb" label="Save a copy" key="s" controlKey="true" enabled="{tableTree.selectedItems.length>0}"/>
</menuitem>
<menuitem label="Table">
<menuitem id="newtable" label="Add table" key="t" controlKey="true" enabled="{tableTree.selectedItems.length>0}"/>
<menuitem id="droptable" label="Drop table" key="d" controlKey="true" enabled="{isTableSelected}"/>
</menuitem>
</root>
</fx:XML>
<fx:XMLList id="dbData">
</fx:XMLList>
<mx:ArrayCollection id="tableData">
</mx:ArrayCollection>
<mx:ArrayCollection id="columnData">
</mx:ArrayCollection>
<mx:ArrayCollection id="conflictTypes">
<fx:String>---</fx:String>
<fx:String>ABORT</fx:String>
<fx:String>FAIL</fx:String>
<fx:String>IGNORE</fx:String>
<fx:String>ROLLBACK</fx:String>
<fx:String>REPLACE</fx:String>
</mx:ArrayCollection>
<mx:ArrayCollection id="dataTypes">
<fx:String>NONE</fx:String>
<fx:String>INTEGER</fx:String>
<fx:String>TEXT</fx:String>
<fx:String>REAL</fx:String>
<fx:String>NUMERIC</fx:String>
</mx:ArrayCollection>
<mx:AdvancedDataGridColumn id="checkboxColumn" headerText=" " width="30" sortable="false" draggable="false" resizable="false" editable="false">
<mx:itemRenderer>
<fx:Component>
<mx:Box width="30" horizontalAlign="center">
<mx:CheckBox selected="@{data.sel}" />
</mx:Box>
</fx:Component>
</mx:itemRenderer>
</mx:AdvancedDataGridColumn>
<mx:TitleWindow id="newTableWindow" title="Create new table" close="closeNewTableWindow();" showCloseButton="true">
<s:VGroup>
<s:HGroup width="100%" verticalAlign="middle">
<s:Label>Table name: </s:Label>
<s:TextInput id="newTableName" />
</s:HGroup>
<s:Button click="createNewTable();" label="Create" width="100%" />
</s:VGroup>
</mx:TitleWindow>
<mx:TitleWindow id="historyWindow" title="SQL History" close="closeHistoryWindow();" showCloseButton="true">
<mx:Box width="100%" height="100%" paddingLeft="10" paddingRight="10" paddingTop="10" paddingBottom="10">
<s:TextArea id="historyText" width="100%" height="100%" editable="false" />
</mx:Box>
</mx:TitleWindow>
</fx:Declarations>

<fx:Script>
<![CDATA[
import flash.data.SQLConnection;
import flash.data.SQLResult;
import flash.data.SQLSchema;
import flash.data.SQLSchemaResult;
import flash.data.SQLStatement;
import flash.errors.SQLError;
import flash.events.Event;
import flash.events.MouseEvent;
import flash.events.SQLEvent;
import flash.filesystem.File;
import flash.net.FileFilter;
import flash.net.FileReference;
import flash.net.Responder;
import flash.ui.ContextMenu;
import flash.ui.ContextMenuItem;
import mx.collections.ArrayCollection;
import mx.controls.advancedDataGridClasses.AdvancedDataGridColumn;
import mx.controls.Alert;
import mx.events.CloseEvent;
import mx.events.FlexNativeMenuEvent;
import mx.managers.PopUpManager;

private var connection:SQLConnection = new SQLConnection();
private var selectedDatabase:String = "";
[Bindable]
private var isTableSelected:Boolean = false;
private var sqlHistory:Array = [];

private function selectAllChange(evt:Event):void {
var i:int;
if (evt.currentTarget.selected) {
for (i = 0; i < tableData.length; i++) {
tableData[i].sel = true;
}
} else
if (!evt.currentTarget.selected) {
for (i = 0; i < tableData.length; i++) {
tableData[i].sel = false;
}
}
tableGrid.invalidateDisplayList();
tableGrid.invalidateList();
}

private function menuSelect(evt:FlexNativeMenuEvent):void {
(evt.item.@id == "newdb")?(newDatabase()):(void);
(evt.item.@id == "opendb")?(openDatabase()):(void);
(evt.item.@id == "newtable")?(newTable()):(void);
(evt.item.@id == "droptable")?(dropTable()):(void);
(evt.item.@id == "savedb")?(saveCopy()):(void);
}

private function newDatabase():void {
var file:File = File.desktopDirectory.resolvePath("Untitled");
file.addEventListener(Event.SELECT, newSelect);
file.browseForSave("Choose where to save the database");
var newDB:XML;
var statement:SQLStatement = new SQLStatement();
function newSelect(evt:Event):void {
if (file.exists) {
Alert.show("File already exists, cannot overwrite.", "Nope");
return;
}
file.nativePath += ".db";
var n:String = parseDatabase(file);
loadDataSchema(n);
}
}

private function openDatabase():void {
var file:File = new File();
file.browseForOpen("Open database", [new FileFilter("Databases", "*.db"), new FileFilter("All files", "*")]);
file.addEventListener(Event.SELECT, openSelect);

function openSelect(evt:Event):void {
var n:String = parseDatabase(file, true);
loadDataSchema(n);
}
}

private function saveCopy():void {
var databasePath:String;
if (selectedDatabase == "main") databasePath = dbData.db[0].@path;
if (selectedDatabase != "main") {
var newNum:int = Number(selectedDatabase.replace("db", ""));
var newInd:int;
for (var i:int = 0; i < dbData.db.length(); i++) {
if (dbData.db[i].@numid == newNum) {
newInd = i;
break;
}
}
databasePath = dbData.db[newInd].@path;
}
var file:File = new File(databasePath);
file.browseForSave("Save copy of database");
file.addEventListener(Event.SELECT, onCopySelect);
function onCopySelect(evt:Event):void {
if(notAlreadyOpen(file)){
var initFile:File = new File(databasePath);
initFile.copyTo(file, true);
}else {
Alert.show("Cannot overwrite a file that is currently open.", "Nope");
}
}
}

private function loadDataSchema(name:String):void {
if (name != "") {
connection.loadSchema(null, null, name, true, new Responder(schemaSuccess, schemaError));
function schemaSuccess(evt:SQLSchemaResult):void {
// Schema found! Now parsing:
var result:SQLSchemaResult = evt;
// Adding tables:
var nid:Number = (name=="main")?(1):(Number(name.replace("db", "")));
var dataNode:XMLList = dbData.db.(@numid == nid);
dataNode.setChildren(<placeholder/>);
delete dataNode.placeholder;
for (var i:int = 0; i < result.tables.length; i++) {
var newTable:XML = new XML(<tb/>);
newTable.@label = result.tables[i].name;
newTable.@isBranch = false;
newTable.@databaseName = name;
dataNode.appendChild(newTable);
}
}
function schemaError(evt:SQLError):void {
// Alert.show("Database is empty");
}
isTableSelected = false;
}
}

private function parseDatabase(file:File, needCheck:Boolean = false):String {
var ret:String = "";
if (!needCheck || file.exists) {
if(!needCheck || notAlreadyOpen(file)){
var newDB:XML;
if (dbData.db.length() == 0) {
connection.open(file);
dbData = new XMLList(<root></root>);
newDB = <db/>
newDB.@label = file.name;
newDB.@numid = 1;
newDB.@isBranch = true;
newDB.@path = file.nativePath;
dbData[0].appendChild(newDB);
ret = "main";
}else
if (dbData.db.length() > 0) {
var newnum:int = dbData.db.length() + 1;
connection.attach("db"+newnum.toString(), file);
newDB = <db/>
newDB.@label = file.name;
newDB.@numid = newnum.toString();
newDB.@isBranch = true;
newDB.@path = file.nativePath;
dbData[0].appendChild(newDB);
ret = "db" + newnum.toString();
}}else {
Alert.show("Database already opened.", "Error");
}
}else {
Alert.show("File not found.", "Error");
}
return ret;
}

private function notAlreadyOpen(file:File):Boolean{ 
var r:Boolean = true;
for (var i:int = 0; i < dbData.db.length(); i++) {
if (file.nativePath == dbData.db[i].@path) {
r = false;
}
}
return r;
}

private function tableSelect():void {
saveTableButton.emphasized = false;
columnData = new ArrayCollection([]);
if(col_name!=null){
col_name.text = "";
col_data.selectedIndex = 0;
col_key.selected = false;
col_auto.selected = false;
col_unique.selected = false;
col_null.selected = false;
col_default.text = "";
col_conflict.selectedIndex = 0;
}
if (tableTree.selectedItem.@isBranch) {
isTableSelected = false;
var dataname:String;
if (tableTree.selectedItem.@numid == 1) dataname = "main";
if (tableTree.selectedItem.@numid > 1) dataname = "db" + tableTree.selectedItem.@numid;
selectedDatabase = dataname;
}
if (tableTree.selectedItem.@isBranch == false) {
isTableSelected = true;
selectedDatabase = tableTree.selectedItem.@databaseName;
tableData = new ArrayCollection([]);
var newColumns:Array = [checkboxColumn];
connection.loadSchema(SQLTableSchema, tableTree.selectedItem.@label, tableTree.selectedItem.@databaseName);
var schema:SQLSchemaResult = connection.getSchemaResult();
for (var i:int = 0; i < schema.tables[0].columns.length; i++) {
columnData.addItem({name:schema.tables[0].columns[i].name});
var aColumn:AdvancedDataGridColumn = new AdvancedDataGridColumn();
aColumn.headerText = schema.tables[0].columns[i].name;
aColumn.dataField = "db_" + schema.tables[0].columns[i].name;
if (schema.tables[0].columns[i].autoIncrement) aColumn.editable = false;
if (schema.tables[0].columns[i].primaryKey) tableTree.selectedItem.@primaryKeyColumn = schema.tables[0].columns[i].name;
newColumns.push(aColumn);
}
tableGrid.columns = newColumns;
var stat:SQLStatement = new SQLStatement();
stat.sqlConnection = connection;
stat.text = "SELECT * FROM " + tableTree.selectedItem.@databaseName + "." + tableTree.selectedItem.@label;
lastStatement(stat.text);
stat.execute(-1, new Responder(tableSuccess, tableError));
}
function tableSuccess(evt:SQLResult):void {
if (evt.data != null) {
for (var item:Object in evt.data) {
var obj:Object = new Object();
for (var value:Object in evt.data[item]) {
obj["db_"+value] = evt.data[item][value];
}
tableData.addItem(obj);
}
}
}
function tableError(evt:SQLError):void {
Alert.show("Unable to read table data.", "Error");
}
}

private function newTable():void {
PopUpManager.addPopUp(newTableWindow, this);
PopUpManager.centerPopUp(newTableWindow);
newTableWindow.title = "Create new table";
focusManager.setFocus(newTableName);
}

private function dropTable():void {
Alert.show("Are you sure you want to completely delete this table?", "Drop table?", Alert.YES | Alert.NO, null, dropConfirm);
function dropConfirm(evt:CloseEvent):void {
if (evt.detail == Alert.YES) {
var stat:SQLStatement = new SQLStatement();
stat.sqlConnection = connection;
stat.text = "DROP TABLE " + selectedDatabase + "." + tableTree.selectedItem.@label;
lastStatement(stat.text);
stat.execute( -1, new Responder(dropTableSuccess, dropTableError));
}
}
function dropTableSuccess(evt:SQLResult):void {
loadDataSchema(selectedDatabase);
}
function dropTableError(evt:SQLError):void {
Alert.show("ERROR:" + evt.details, "Error");
}
}

private function closeNewTableWindow():void{
PopUpManager.removePopUp(newTableWindow);
}

private function createNewTable():void {
var stat:SQLStatement = new SQLStatement();
stat.sqlConnection = connection;
stat.text = "CREATE TABLE IF NOT EXISTS " + selectedDatabase + "." + newTableName.text + "(id INTEGER PRIMARY KEY AUTOINCREMENT, blankColumn TEXT)";
lastStatement(stat.text);
stat.execute( -1, new Responder(newTableSuccess, newTableError));
function newTableSuccess(evt:SQLResult):void {
closeNewTableWindow();
loadDataSchema(selectedDatabase);
}
function newTableError(evt:SQLError):void {
Alert.show("ERROR:" + evt.details, "Error");
}
}

private function lastStatement(text:String):void {
statementText.text = text;
sqlHistory.push(text);
}

private function openHistory():void {
PopUpManager.addPopUp(historyWindow, this);
historyWindow.width = width - 100;
historyWindow.height = height - 100;
PopUpManager.centerPopUp(historyWindow);
historyText.text = "";
for (var i:int = sqlHistory.length - 1; i >= 0; i--) {
historyText.appendText(sqlHistory[i] + "\n");
}
}

private function closeHistoryWindow():void {
PopUpManager.removePopUp(historyWindow);
}

private function saveTable():void {
var keyColumnName:String = tableTree.selectedItem.@primaryKeyColumn;
// clear all "sel" and store them in a temp array
var tempSel:Array = [];
for (var s:int = 0; s < tableData.length; s++) {
if (tableData[s].sel) {
tempSel.push(true);
tableData[s].sel = false;
}else
if (!tableData[s].sel) {
tempSel.push(false);
}
}
// update each row
for (var i:int = 0; i < tableData.length; i++) {
var stat:SQLStatement = new SQLStatement();
var sqlStat:String = "UPDATE " + selectedDatabase + "." + tableTree.selectedItem.@label + " SET";
// add each attribute as parameter
for (var attribute:String in tableData[i]) {
// if column is not our CheckBox column or the key column
if (attribute != "mx_internal_uid" && attribute!=keyColumnName && attribute!="sel") {
// add value as parameter
stat.parameters["@" + attribute.substr(3)] = tableData[i][attribute];
sqlStat += " " + attribute.substr(3) + "=@" + attribute.substr(3) + ",";
}
}
// remove the last comma
sqlStat = sqlStat.substr(0, sqlStat.length - 1);
sqlStat += " WHERE " + keyColumnName + "=" + tableData[i]["db_"+keyColumnName];
stat.sqlConnection = connection;
stat.text = sqlStat;
lastStatement(stat.text);
stat.execute( -1, new Responder(saveSuccess, saveError));
}

function saveSuccess(evt:SQLResult):void {
}

function saveError(evt:SQLError):void {
Alert.show("ERROR: " + evt.details, "Error");
}

tableSelect();
for (var t:int = 0; t < tableData.length; t++) {
if (tempSel[t]) tableData[t].sel=true;
}
tableGrid.invalidateDisplayList();
tableGrid.invalidateList();
}

private function deleteSelected():void {
var keyColumnName:String = tableTree.selectedItem.@primaryKeyColumn;
for (var i:int = 0; i < tableData.length; i++) {
if (tableData[i].sel) {
var stat:SQLStatement = new SQLStatement();
stat.sqlConnection = connection;
stat.text = "DELETE FROM " + selectedDatabase + "." + tableTree.selectedItem.@label + " WHERE " + keyColumnName + "=" + tableData[i]["db_" + keyColumnName];
lastStatement(stat.text);
stat.execute( -1, new Responder(deleteSuccess, deleteError));
}
}
tableSelect();
tableGrid.invalidateDisplayList();
tableGrid.invalidateList();

function deleteSuccess(evt:SQLResult):void {
}
function deleteError(evt:SQLError):void {
Alert.show("ERROR: " + evt.details, "Error");
}
}

private function newRecord():void {
var stat:SQLStatement = new SQLStatement();
stat.sqlConnection = connection;
stat.text = "INSERT INTO " + selectedDatabase + "." + tableTree.selectedItem.@label + " DEFAULT VALUES;";
lastStatement(stat.text);
stat.execute( -1, new Responder(newSuccess, newError));

function newSuccess(evt:SQLResult):void {
tableSelect();
tableGrid.invalidateDisplayList();
tableGrid.invalidateList();
}
function newError(evt:SQLError):void {
Alert.show("ERROR: " + evt.details, "Error");
}
}

private function columnSelect():void {
connection.loadSchema(SQLTableSchema, tableTree.selectedItem.@label, tableTree.selectedItem.@databaseName);
var schema:SQLSchemaResult = connection.getSchemaResult();
var fullSQL:String = schema.tables[0].sql;
// extract the text inside the ( )
fullSQL = fullSQL.substring( fullSQL.indexOf("(") + 1 , fullSQL.lastIndexOf(")") );
// split all columns into an array
var columns:Array = fullSQL.split(",");
// get the currently selected column
var currentColumn:String = columns[columnList.selectedIndex];
// delete the name of the column from this text
var currentParameters:String = currentColumn.substr(currentColumn.indexOf(columnList.selectedItem.name) + columnList.selectedItem.name.length + 1);
// find DEFAULT and extract it
var defaultMatch:String = "";
var defaultPattern:RegExp = /((DEFAULT)\s((".+")|([0-9]+)))/i;
if (currentParameters.match(defaultPattern)) {
defaultMatch = currentParameters.match(defaultPattern)[0];
// delete it from currentParameters
currentParameters = currentParameters.replace(defaultMatch, "");
// delete "DEFAULT" from the match
defaultMatch = defaultMatch.substr(8);
// if any quotes are found, remove the first and last symbols
if (defaultMatch.indexOf('"') != -1) {
defaultMatch = defaultMatch.substring(1, defaultMatch.length - 1);
}
}
// find ON CONFLICT and extract it
var conflictMatch:String = "";
var conflictPattern:RegExp = /((ON CONFLICT)\s(ABORT|FAIL|IGNORE|ROLLBACK|REPLACE))/i;
if (currentParameters.match(conflictPattern)) {
conflictMatch = currentParameters.match(conflictPattern)[0];
// delete it from currentParameters
currentParameters = currentParameters.replace(conflictMatch, "");
// delete "ON CONFLICT" from the match
conflictMatch = conflictMatch.substr(12);
}
// apply values
col_name.text = columnList.selectedItem.name;
col_key.selected = (currentParameters.toUpperCase().indexOf("PRIMARY KEY") != -1)?(true):(false);
col_auto.selected = (currentParameters.toUpperCase().indexOf("AUTOINCREMENT") != -1)?(true):(false);
col_unique.selected = (currentParameters.toUpperCase().lastIndexOf("UNIQUE") != -1)?(true):(false);
col_null.selected = (currentParameters.toUpperCase().indexOf("NOT NULL") != -1)?(false):(true);
col_default.text = defaultMatch;
col_conflict.selectedIndex = 0;
if (conflictMatch.toUpperCase() == "ABORT") col_conflict.selectedIndex = 1;
if (conflictMatch.toUpperCase() == "FAIL") col_conflict.selectedIndex = 2;
if (conflictMatch.toUpperCase() == "IGNORE") col_conflict.selectedIndex = 3;
if (conflictMatch.toUpperCase() == "ROLLBACK") col_conflict.selectedIndex = 4;
if (conflictMatch.toUpperCase() == "REPLACE") col_conflict.selectedIndex = 5;

// read data type
col_data.textInput.text = schema.tables[0].columns[columnList.selectedIndex].dataType;

// enable or disable ON CONFLICT
checkConflict();
// unhighlight "Update selected"
col_b_update.emphasized = false;
}

private function checkConflict():void {
if (col_key.selected || !col_null.selected || col_unique.selected) {
col_conflict.enabled = true;
}else {
col_conflict.enabled = false;
}
}

private function formChange():void {
checkConflict();
if (columnList.selectedItems.length > 0) {
col_b_update.emphasized = true;
}
}

private function addColumn():void {
col_b_update.emphasized = false;
var prevTableName:String = tableTree.selectedItem.@label;
if (col_name.text != "" && col_data.textInput.text != "" && (col_null.selected || col_default.text != "")) {
connection.loadSchema(SQLTableSchema, tableTree.selectedItem.@label, tableTree.selectedItem.@databaseName);
var schema:SQLSchemaResult = connection.getSchemaResult();
var fullSQL:String = schema.tables[0].sql;
// extract the text inside the ( )
fullSQL = fullSQL.substring( fullSQL.indexOf("(") + 1 , fullSQL.lastIndexOf(")") );
var sqlText:String = "CREATE TABLE " + selectedDatabase + "." + tableTree.selectedItem.@label + " (";
sqlText += fullSQL + ", ";
// add the new column
sqlText += col_name.text + " " + col_data.textInput.text + " ";
if (col_key.selected) sqlText += "PRIMARY KEY ";
if (col_key.selected && col_conflict.selectedIndex > 0) sqlText += "ON CONFLICT " + col_conflict.selectedLabel + " ";
if (col_key.selected && col_auto.selected) sqlText += "AUTOINCREMENT ";
if (!col_null.selected) sqlText += "NOT NULL ";
if (!col_null.selected && col_conflict.selectedIndex > 0) sqlText += "ON CONFLICT " + col_conflict.selectedLabel + " ";
if (col_unique.selected) sqlText += "UNIQUE ";
if (col_unique.selected && col_conflict.selectedIndex > 0) sqlText += "ON CONFLICT " + col_conflict.selectedLabel + " ";
if (col_default.text != "") {
sqlText += "DEFAULT ";
if (isNaN(Number(col_default.text))) sqlText += '"' + col_default.text + '"';
if (!isNaN(Number(col_default.text))) sqlText += col_default.text;
}
sqlText += ");";
lastStatement(sqlText);

// Create backup
var backupName:String = "backup";
while (!tableIsUnique(backupName)) {
backupName += "0";
}
var bstat:SQLStatement = new SQLStatement();
bstat.sqlConnection = connection;
bstat.text = "CREATE TABLE " + selectedDatabase + "." + backupName + " (" + fullSQL + ");";
bstat.execute();

// Copy data to backup
var cstat:SQLStatement = new SQLStatement();
cstat.sqlConnection = connection;
cstat.text = "INSERT INTO " + selectedDatabase + "." + backupName + " SELECT * FROM " + selectedDatabase + "." + tableTree.selectedItem.@label;
cstat.execute();

// Delete initial table
var dstat:SQLStatement = new SQLStatement();
dstat.sqlConnection = connection;
dstat.text = "DROP TABLE " + selectedDatabase + "." + tableTree.selectedItem.@label;
dstat.execute();

// Create new table
var stat:SQLStatement = new SQLStatement();
stat.sqlConnection = connection;
stat.text = sqlText;
stat.execute( -1, new Responder(newColumnSuccess, newColumnError));
}else {
Alert.show("Please fill all the required fields!", "Error");
}
function newColumnSuccess(evt:SQLResult):void {
// Insert previous values
var istat:SQLStatement = new SQLStatement();
istat.sqlConnection = connection;
istat.text = "INSERT INTO " + selectedDatabase + "." + prevTableName + " (" + columnNames() + ") SELECT " + columnNames() + " FROM " + selectedDatabase + "." + backupName;
istat.execute();
// Delete backup
var bdstat:SQLStatement = new SQLStatement();
bdstat.sqlConnection = connection;
bdstat.text = "DROP TABLE " + selectedDatabase + "." + backupName;
bdstat.execute();
tableSelect();
}
function newColumnError(evt:SQLError):void {
Alert.show("ERROR: " + evt.details + "\n\nRestoring the database using backup...", "Error");
// Restore table
var rstat:SQLStatement = new SQLStatement();
rstat.sqlConnection = connection;
rstat.text = "ALTER TABLE " + selectedDatabase + "." + backupName + " RENAME TO " + prevTableName
rstat.execute();
tableSelect();
}
}

private function tableIsUnique(name:String):Boolean {
var r:Boolean = true;
for (var i:int = 0; i < dbData..tb.length(); i++) {
if (dbData..tb[i].@label == name) {
r = false;
break;
}
}
return r;
}

private function columnNames():String {
var r:String = "";
for (var i:int = 0; i < columnData.length; i++) {
r += columnData[i].name;
if (i < columnData.length - 1) r += ", ";
}
return r;
}
]]>
</fx:Script>

<s:HGroup gap="0" width="100%" height="100%">
<s:VGroup width="200" height="100%" gap="0">
<s:HGroup>
<s:Button label="New table" click="newTable();" enabled="{tableTree.selectedItems.length>0}"/>
<s:Button label="Drop table" click="dropTable();" enabled="{isTableSelected}" />
</s:HGroup>
<mx:Tree id="tableTree" width="100%" height="100%" dataProvider="{dbData}" showRoot="false" labelField="@label" itemClick="tableSelect();"/>
</s:VGroup>
<s:VGroup width="100%" height="100%" gap="0">
<mx:Box height="80" width="100%">
<s:VGroup paddingTop="10" paddingLeft="10" paddingRight="10" paddingBottom="10" width="100%" height="100%">
<s:HGroup width="100%" verticalAlign="middle">
<s:Label width="100%">Latest SQL statement:</s:Label>
<s:Button width="100" label="View history" click="openHistory();" />
</s:HGroup>
<s:TextArea id="statementText" editable="false" width="100%" height="30"/>
</s:VGroup>
</mx:Box>
<mx:TabNavigator width="100%" height="100%" paddingTop="0">
<s:NavigatorContent label="Table contents">
<s:VGroup width="100%" height="100%" gap="0">
<mx:HBox width="100%" height="30" paddingLeft="8" paddingTop="6">
<mx:CheckBox label="Select all" change="selectAllChange(event);" />
<s:Button label="Delete selected" enabled="{isTableSelected}" click="deleteSelected();" />
<s:Button id="saveTableButton" label="Save changes" click="saveTable();" enabled="{isTableSelected}"/>
<s:Button id="newRecordButton" label="Add a record" click="newRecord();" enabled="{isTableSelected}"/>
</mx:HBox>
<mx:AdvancedDataGrid id="tableGrid" width="100%" height="100%" dataProvider="{tableData}" editable="true" itemEditBegin="saveTableButton.emphasized=true;">
<mx:columns>
<mx:AdvancedDataGridColumn dataField="" headerText="Data" editable="false" />
</mx:columns>
</mx:AdvancedDataGrid>
</s:VGroup>
</s:NavigatorContent>
<s:NavigatorContent label="Edit columns">
<s:HGroup width="100%" height="100%" >
<mx:List id="columnList" width="200" height="100%" dataProvider="{columnData}" labelField="name" change="columnSelect();" />
<s:VGroup height="100%" paddingTop="10">
<s:HGroup>
<s:Button id="col_b_add" label="Add column" enabled="{isTableSelected}" click="addColumn();" />
<s:Button id="col_b_update" label="Update selected" enabled="{columnList.selectedItems.length > 0}" />
<s:Button id="col_b_delete" label="Delete selected" enabled="{columnList.selectedItems.length > 0}" />
</s:HGroup>
<mx:Form enabled="{isTableSelected}">
<mx:FormItem label="Name" required="true">
<s:TextInput id="col_name" change="formChange();"/>
</mx:FormItem>
<mx:FormItem label="Data type" required="true">
<s:ComboBox id="col_data" dataProvider="{dataTypes}" change="formChange();"/>
</mx:FormItem>
<mx:FormItem label="Primary Key">
<s:CheckBox id="col_key" change="formChange();" />
</mx:FormItem>
<mx:FormItem label="AutoIncrement">
<s:CheckBox id="col_auto" change="formChange();" enabled="{col_key.selected}" />
</mx:FormItem>
<mx:FormItem label="Unique">
<s:CheckBox id="col_unique" change="formChange();" />
</mx:FormItem>
<mx:FormItem label="Allow Null">
<s:CheckBox id="col_null" change="formChange();" selected="true" />
</mx:FormItem>
<mx:FormItem label="Default Value" required="{!col_null.selected}">
<s:TextArea id="col_default" change="formChange();"/>
</mx:FormItem>
<mx:FormItem label="On Conflict">
<mx:ComboBox id="col_conflict" dataProvider="{conflictTypes}" editable="false" change="formChange();"/>
</mx:FormItem>
</mx:Form>
</s:VGroup>
</s:HGroup>
</s:NavigatorContent>
<s:NavigatorContent label="Query">

</s:NavigatorContent>
</mx:TabNavigator>
</s:VGroup>
</s:HGroup>

</s:WindowedApplication>

Thanks for reading!

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