Saturday, May 12, 2012

KirSQLite - Flex AIR Database Manager: Part 11

In this tutorial we'll sort out the native menu by assigning some of the existing features to the menu items. We'll also add an ability to save a copy of a database (backup).

Firstly, go to the windowMenu XML object and edit its contents by adding a "Save a copy" menu item to the existing two under the "Database" menu. Set the subchildren of the "Table" menu to two items - "Add table" and "Drop table". Set their shortcuts, enabled and id properties as shown below:

<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>

Now go to menuSelect and assign handler functions for each of the menu items. Set the "newtable" and "droptable" handlers to existing newTable() and dropTable() functions, and the new "saveddb" item's handler to a new function saveCopy():

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);
}

The function first finds out the path of the current database. The selectedDatabase value contains the sql name of the database. If the selectedDatabase's value is "main", then it's easy - the database is the first one in the dbData xml.

If the value is not main, it consists of "db" with a number, for example, "db3". We can take the "db" away to get the number and find which database item in dbData has the same numid attribute value as this number. Then we use the index of that item in the XML to find out the path to this database:

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;
}

After that, we create a File object to open a new browse window to let the user select the destination of the copy. After it is selected, we check if the selected file is already opened in our application. If it is, abort operation, because this might raise problems. Create a new File object of the initial database and use its copyTo() method to copy the file:

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");
}
}

Full function code:

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");
}
}
}

The feature we added today will be useful to developers to be able to quickly backup databases before attempting to do anything with them.

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: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(evt:Event):void {
if (evt.currentTarget.selectedItem.@isBranch) {
isTableSelected = false;
var dataname:String;
if (evt.currentTarget.selectedItem.@numid == 1) dataname = "main";
if (evt.currentTarget.selectedItem.@numid > 1) dataname = "db" + evt.currentTarget.selectedItem.@numid;
selectedDatabase = dataname;
}
if (evt.currentTarget.selectedItem.@isBranch == false) {
isTableSelected = true;
selectedDatabase = evt.currentTarget.selectedItem.@databaseName;
tableData = new ArrayCollection([]);
var newColumns:Array = [checkboxColumn];
connection.loadSchema(SQLTableSchema, evt.currentTarget.selectedItem.@label, evt.currentTarget.selectedItem.@databaseName);
var schema:SQLSchemaResult = connection.getSchemaResult();
for (var i:int = 0; i < schema.tables[0].columns.length; i++) {
var aColumn:AdvancedDataGridColumn = new AdvancedDataGridColumn(schema.tables[0].columns[i].name);
newColumns.push(aColumn);
}
tableGrid.columns = newColumns;
var stat:SQLStatement = new SQLStatement();
stat.sqlConnection = connection;
stat.text = "SELECT * FROM " + evt.currentTarget.selectedItem.@databaseName + "." + evt.currentTarget.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[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);
}
]]>
</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(event);"/>
</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"/>
</mx:HBox>
<mx:AdvancedDataGrid id="tableGrid" width="100%" height="100%" dataProvider="{tableData}" editable="true">
<mx:columns>
<mx:AdvancedDataGridColumn dataField="" headerText="Data" editable="false" />
</mx:columns>
</mx:AdvancedDataGrid>
</s:VGroup>
</s:NavigatorContent>
<s:NavigatorContent label="Edit columns">

</s:NavigatorContent>
<s:NavigatorContent label="Query">

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

</s:WindowedApplication>

Thanks for reading!

No comments:

Post a Comment