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  • CNC Information - Data Storage and Transfer

    A CNC machine must be tried when there is need to improve speed and accuracy. The machine performs better in doing repetitive tasks and getting large jobs done quicker. Woodworking shops or industria... [Author: Scheygen Smith - Computers and Internet - March 21, 2010]

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  • On Building a Data-Driven E-Commerce Site

    The following is a preprint of an article for the NDC Magazine to be published in Apri.   It had been a long, hard week at work. I had my feet up and was calling my long-distance girlfriend when she popped the question: “Do you know how to build web sites?”   That was about a month ago and, after swearing to her that I spent my days helping other people build their web sites, so I should oughta know a thing or two about how to build one for her. After some very gentle requirements...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Microsoft Silverlight 4 Data and Services Cookbook

    Alas I find my self doing another book review... its not clear to me that I should continue to do that but on this particular book it heads in the right direction. As noted in an earlier post I find the idea of a cook book to be of particular interest and useful in my work with Silverlight. This book has gotten closer then any other to date in building the ideal Silverlight book. Albeit the book does make an attempt to teach Silverlight to some degree but it tends to be more of a reference book,...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • ??????Oracle Developer Tools for Visual Studio(ODT)???

    - by Yusuke.Yamamoto
    ????? ??:2010/11/12 ??:???? Oracle ??Oracle Developer Tools for Visual Studio(???ODT)????? Visual Studio ??????????????????ODT ????????????????????ODT ????????????SQL*Plus ???????????????????????·????????????Oracle??????·????????????????? ?????????????ODT ???????ODT ???????Visual Studio ?? ODT ???Visual Studio ?? Oracle??????·????????????????? ????????? ????????????????? http://codezine.jp/article/detail/5499

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  • Data won't save to SQL database, getting error "close() was never explicitly called on database"

    - by SnowLeppard
    I have a save button in the activity where the user enters data which does this: String subjectName = etName.getText().toString(); String subjectColour = etColour.getText().toString(); SQLDatabase entrySubject = new SQLDatabase(AddSubject.this); entrySubject.open(); entrySubject.createSubjectEntry(subjectName, subjectColour); entrySubject.close(); Which refers to this SQL database class: package com.***.schooltimetable; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.SQLException; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; public class SQLDatabase { public static final String KEY_SUBJECTS_ROWID = "_id"; public static final String KEY_SUBJECTNAME = "name"; public static final String KEY_COLOUR = "colour"; private static final String DATABASE_NAME = "Database"; private static final String DATABASE_TABLE_SUBJECTS = "tSubjects"; private static final int DATABASE_VERSION = 1; private DbHelper ourHelper; private final Context ourContext; private SQLiteDatabase ourDatabase; private static class DbHelper extends SQLiteOpenHelper { public DbHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); // TODO Auto-generated constructor stub } @Override public void onCreate(SQLiteDatabase db) { // TODO Auto-generated method stub db.execSQL("CREATE TABLE " + DATABASE_TABLE_SUBJECTS + " (" + KEY_SUBJECTS_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_SUBJECTNAME + " TEXT NOT NULL, " + KEY_COLOUR + " TEXT NOT NULL);"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // TODO Auto-generated method stub db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE_SUBJECTS); onCreate(db); } } public SQLDatabase(Context c) { ourContext = c; } public SQLDatabase open() throws SQLException { ourHelper = new DbHelper(ourContext); ourDatabase = ourHelper.getWritableDatabase(); return this; } public void close() { ourHelper.close(); } public long createSubjectEntry(String subjectName, String subjectColour) { // TODO Auto-generated method stub ContentValues cv = new ContentValues(); cv.put(KEY_SUBJECTNAME, subjectName); cv.put(KEY_COLOUR, subjectColour); return ourDatabase.insert(DATABASE_TABLE_SUBJECTS, null, cv); } public String[][] getSubjects() { // TODO Auto-generated method stub String[] Columns = new String[] { KEY_SUBJECTNAME, KEY_COLOUR }; Cursor c = ourDatabase.query(DATABASE_TABLE_SUBJECTS, Columns, null, null, null, null, null); String[][] Result = new String[1][]; // int iRow = c.getColumnIndex(KEY_LESSONS_ROWID); int iName = c.getColumnIndex(KEY_SUBJECTNAME); int iColour = c.getColumnIndex(KEY_COLOUR); for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) { Result[0][c.getPosition()] = c.getString(iName); Result[1][c.getPosition()] = c.getString(iColour); Settings.subjectCount = c.getPosition(); TimetableEntry.subjectCount = c.getPosition(); } return Result; } This class has other variables and other variations of the same methods for multiple tables in the database, i've cut out the irrelevant ones. I'm not sure what I need to close and where, I've got the entrySubject.close() in my activity. I used the methods for the database from the NewBoston tutorials. Can anyone see what I've done wrong, or where my problem is? Thanks.

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  • Service with intents not working. Help needed

    - by tristan202
    I need help in making my click intents work. I used to have them in my appwidgetprovider, but decided to move them into a service, but I am having trouble getting it to work. Below is the entire code from my intentservice: public class IntentService extends Service { static final String ACTION_UPDATE = "android.tristan.widget.digiclock.action.UPDATE_2"; private final static IntentFilter sIntentFilter; public int layoutID = R.layout.clock; int appWidgetIds = 0; static { sIntentFilter = new IntentFilter(); } @Override public IBinder onBind(Intent intent) { return null; } @Override public void onStart(Intent intent, int startId) { super.onStart(intent, startId); } @Override public void onCreate() { super.onCreate(); registerReceiver(onClickTop, sIntentFilter); registerReceiver(onClickBottom, sIntentFilter); Log.d("DigiClock IntentService", "IntentService Started."); } @Override public void onDestroy() { super.onDestroy(); unregisterReceiver(onClickTop); unregisterReceiver(onClickBottom); } private final BroadcastReceiver onClickTop = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { if(intent.getAction().equals("android.tristan.widget.digiclock.CLICK")) { PackageManager packageManager = context.getPackageManager(); Intent alarmClockIntent = new Intent(Intent.ACTION_MAIN).addCategory(Intent.CATEGORY_LAUNCHER); String clockImpls[][] = { {"HTC Alarm Clock", "com.htc.android.worldclock", "com.htc.android.worldclock.WorldClockTabControl" }, {"Standar Alarm Clock", "com.android.deskclock", "com.android.deskclock.AlarmClock"}, {"Froyo Nexus Alarm Clock", "com.google.android.deskclock", "com.android.deskclock.DeskClock"}, {"Moto Blur Alarm Clock", "com.motorola.blur.alarmclock", "com.motorola.blur.alarmclock.AlarmClock"} }; boolean foundClockImpl = false; for(int i=0; i<clockImpls.length; i++) { String vendor = clockImpls[i][0]; String packageName = clockImpls[i][1]; String className = clockImpls[i][2]; try { ComponentName cn = new ComponentName(packageName, className); ActivityInfo aInfo = packageManager.getActivityInfo(cn, PackageManager.GET_META_DATA); alarmClockIntent.setComponent(cn); foundClockImpl = true; } catch (NameNotFoundException e) { Log.d("Error, ", vendor + " does not exist"); } } if (foundClockImpl) { Vibrator vibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE); vibrator.vibrate(50); final RemoteViews views = new RemoteViews(context.getPackageName(), layoutID); views.setOnClickPendingIntent(R.id.TopRow, PendingIntent.getActivity(context, 0, new Intent(context, DigiClock.class).setFlags(Intent.FLAG_ACTIVITY_NEW_TASK), PendingIntent.FLAG_UPDATE_CURRENT)); AppWidgetManager.getInstance(context).updateAppWidget(intent.getIntArrayExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS), views); alarmClockIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); context.startActivity(alarmClockIntent); } } } }; private final BroadcastReceiver onClickBottom = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { if(intent.getAction().equals("android.tristan.widget.digiclock.CLICK_2")) { PackageManager calendarManager = context.getPackageManager(); Intent calendarIntent = new Intent(Intent.ACTION_MAIN).addCategory(Intent.CATEGORY_LAUNCHER); String calendarImpls[][] = { {"HTC Calendar", "com.htc.calendar", "com.htc.calendar.LaunchActivity" }, {"Standard Calendar", "com.android.calendar", "com.android.calendar.LaunchActivity"}, {"Moto Blur Calendar", "com.motorola.blur.calendar", "com.motorola.blur.calendar.LaunchActivity"} }; boolean foundCalendarImpl = false; for(int i=0; i<calendarImpls.length; i++) { String vendor = calendarImpls[i][0]; String packageName = calendarImpls[i][1]; String className = calendarImpls[i][2]; try { ComponentName cn = new ComponentName(packageName, className); ActivityInfo aInfo = calendarManager.getActivityInfo(cn, PackageManager.GET_META_DATA); calendarIntent.setComponent(cn); foundCalendarImpl = true; } catch (NameNotFoundException e) { Log.d("Error, ", vendor + " does not exist"); } } if (foundCalendarImpl) { Vibrator vibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE); vibrator.vibrate(50); final RemoteViews views2 = new RemoteViews(context.getPackageName(), layoutID); views2.setOnClickPendingIntent(R.id.BottomRow, PendingIntent.getActivity(context, 0, new Intent(context, DigiClock.class).setFlags(Intent.FLAG_ACTIVITY_NEW_TASK), PendingIntent.FLAG_UPDATE_CURRENT)); AppWidgetManager.getInstance(context).updateAppWidget(intent.getIntArrayExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS), views2); calendarIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); context.startActivity(calendarIntent); } } }; }; ;}; What am I doing wrong here?

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  • Data adapter not filling my dataset

    - by Doug Ancil
    I have the following code: Imports System.Data.SqlClient Public Class Main Protected WithEvents DataGridView1 As DataGridView Dim instForm2 As New Exceptions Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles startpayrollButton.Click Dim ssql As String = "select MAX(payrolldate) AS [payrolldate], " & _ "dateadd(dd, ((datediff(dd, '17530107', MAX(payrolldate))/7)*7)+7, '17530107') AS [Sunday]" & _ "from dbo.payroll" & _ " where payrollran = 'no'" Dim oCmd As System.Data.SqlClient.SqlCommand Dim oDr As System.Data.SqlClient.SqlDataReader oCmd = New System.Data.SqlClient.SqlCommand Try With oCmd .Connection = New System.Data.SqlClient.SqlConnection("Initial Catalog=mdr;Data Source=xxxxx;uid=xxxxx;password=xxxxx") .Connection.Open() .CommandType = CommandType.Text .CommandText = ssql oDr = .ExecuteReader() End With If oDr.Read Then payperiodstartdate = oDr.GetDateTime(1) payperiodenddate = payperiodstartdate.AddSeconds(604799) Dim ButtonDialogResult As DialogResult ButtonDialogResult = MessageBox.Show(" The Next Payroll Start Date is: " & payperiodstartdate.ToString() & System.Environment.NewLine & " Through End Date: " & payperiodenddate.ToString()) If ButtonDialogResult = Windows.Forms.DialogResult.OK Then exceptionsButton.Enabled = True startpayrollButton.Enabled = False End If End If oDr.Close() oCmd.Connection.Close() Catch ex As Exception MessageBox.Show(ex.Message) oCmd.Connection.Close() End Try End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles exceptionsButton.Click Dim connection As System.Data.SqlClient.SqlConnection Dim adapter As System.Data.SqlClient.SqlDataAdapter = New System.Data.SqlClient.SqlDataAdapter Dim connectionString As String = "Initial Catalog=mdr;Data Source=xxxxx;uid=xxxxx;password=xxxxx" Dim ds As New DataSet Dim _sql As String = "SELECT [Exceptions].Employeenumber,[Exceptions].exceptiondate, [Exceptions].starttime, [exceptions].endtime, [Exceptions].code, datediff(minute, starttime, endtime) as duration INTO scratchpad3" & _ " FROM Employees INNER JOIN Exceptions ON [Exceptions].EmployeeNumber = [Exceptions].Employeenumber" & _ " where [Exceptions].exceptiondate between @payperiodstartdate and @payperiodenddate" & _ " GROUP BY [Exceptions].Employeenumber, [Exceptions].Exceptiondate, [Exceptions].starttime, [exceptions].endtime," & _ " [Exceptions].code, [Exceptions].exceptiondate" connection = New SqlConnection(connectionString) connection.Open() Dim _CMD As SqlCommand = New SqlCommand(_sql, connection) _CMD.Parameters.AddWithValue("@payperiodstartdate", payperiodstartdate) _CMD.Parameters.AddWithValue("@payperiodenddate", payperiodenddate) adapter.SelectCommand = _CMD Try adapter.Fill(ds) If ds Is Nothing OrElse ds.Tables.Count = 0 OrElse ds.Tables(0).Rows.Count = 0 Then 'it's empty MessageBox.Show("There was no data for this time period. Press Ok to continue", "No Data") connection.Close() Exceptions.saveButton.Enabled = False Exceptions.Hide() Else connection.Close() End If Catch ex As Exception MessageBox.Show(ex.ToString) connection.Close() End Try Exceptions.Show() End Sub Private Sub payrollButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles payrollButton.Click Payrollfinal.Show() End Sub End Class and when I run my program and press this button Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles exceptionsButton.Click I have my date range within a time that I know that my dataset should produce a result, but when I put a line break in my code here: adapter.Fill(ds) and look at it in debug, I show a table value of 0. If I run the same query that I have to produce these results in sql analyser, I see 1 result. Can someone see why my query on my form produces a different result than the sql analyser does? Also here is my schema for my two tables: Exceptions employeenumber varchar no 50 yes no no SQL_Latin1_General_CP1_CI_AS exceptiondate datetime no 8 yes (n/a) (n/a) NULL starttime datetime no 8 yes (n/a) (n/a) NULL endtime datetime no 8 yes (n/a) (n/a) NULL duration varchar no 50 yes no no SQL_Latin1_General_CP1_CI_AS code varchar no 50 yes no no SQL_Latin1_General_CP1_CI_AS approvedby varchar no 50 yes no no SQL_Latin1_General_CP1_CI_AS approved varchar no 50 yes no no SQL_Latin1_General_CP1_CI_AS time timestamp no 8 yes (n/a) (n/a) NULL employees employeenumber varchar no 50 no no no SQL_Latin1_General_CP1_CI_AS name varchar no 50 no no no SQL_Latin1_General_CP1_CI_AS initials varchar no 50 no no no SQL_Latin1_General_CP1_CI_AS loginname1 varchar no 50 yes no no SQL_Latin1_General_CP1_CI_AS

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  • Java: how to tell if a line in a text file was supposed to be blank?

    - by defn
    I'm working on a project in which I have to read in a Grammar file (breaking it up into my data structure), with the goal of being able to generate a random "DearJohnLetter". My problem is that when reading in the .txt file, I don't know how find out whether the file was supposed to be a completely blank line or not, which is detrimental to the program. Here is an example of part of the file, How do i tell if the next line was supposed to be a blank line? (btw I'm just using a buffered reader) Thanks! <start> I have to break up with you because <reason> . But let's still <disclaimer> . <reason> <dubious-excuse> <dubious-excuse> , and also because <reason> <dubious-excuse> my <person> doesn't like you I'm in love with <another> I haven't told you this before but <harsh> I didn't have the heart to tell you this when we were going out, but <harsh> you never <romantic-with-me> with me any more you don't <romantic> any more my <someone> said you were bad news

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  • ExtJs store, how to load data using a MemoryProxy

    - by Miau
    Hi there I m trying to load a json store using a MemoryProxy ( i need to use a proxy because I use different sources depending on scenarios) it kinda looks like this var data = Ext.decode(gridArrayData); var proxy = new Ext.data.MemoryProxy(data); var store = new Ext.data.GroupingStore({ proxy: proxy }); however when I inspect this I can see that the proxy has 10 rows of data, but not the store I m lost as to why Any pointers?

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  • JQuery getJSON Callback Returning Null Data

    - by user338828
    I have a getJSON call that is called back correctly, but the data variable is null. The python code posted below is executed by the getJSON call to the demandURL. Any ideas? javascript: var demandURL = "/demand/washington/"; $.getJSON(demandURL, function(data) { console.log(data); }); python: data = {"demand_count":"one"} json = simplejson.dumps(data) return HttpResponse(json, mimetype="application/json")

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  • Oracle sample data problems

    - by Jay
    So, I have this java based data trasformation / masking tool, which I wanted to test out on Oracle 10g. The good part with Oracle 10g is that you get a load of sample schemas with half a million records in some. The schemas are : SH, OE, HR, IX and etc. So, I installed 10g, found out that the installation scripts are under ORACLE_HOME/demo/scripts. I customized these scripts a bit to run in batch mode. That solves one half of my requirement - to create source data for my testing my data transformation software. The second half of the requirement is that I create the same schemas under different names (TR_HR, TR_OE and so on...) without any data. These schemas would represent my target schemas. So, in short, my software would pick up data from a table in a schema and load it up in to the same table in a different schema. Now, I have two issues in creating my target schema and emptying it. I would like this in a batch job. But the oracle scripts you get, the sample schema names are not configurable. So, I tried creating a script, replacing OE with TR_OE, HR with TR_HR and so on. However, this approach is kind of irritating coz the sample schemas are kind of complicated in the way they are created; Oracle creates synonyms, views, materialized views, data types and lot of weird stuff. I would like the target schemas (TR_HR, TR_OE,...) to be empty. But some of the schemas have circular references, which would not allow me to delete data. The only work around seems to be removing certain foreign keys, deleting data and then adding the constraints back. Is there any easy way to all this, without all this fuss? I would need a complicated data set for my testing (complicated as in tables with triggers, multiple hierarchies.. for instance.. a child table that has children up to 5 levels, a parent table that refers to an IOT table and an IOT table that refers to a non-IOT table etc..). The sample schemas are just about perfect from a data set perspective. The only challenge I see is in automating this whole process of loading up the source schemas, and then creating the target schemas and emptying them. Appreciate your help and suggestions.

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  • Android: handle unexpected internet disconnect while downloading data

    - by M.A. Cape
    Hi, I have here a function that downloads data from a remote server to file. I am still not confident with my code. My question is, what if while reading the stream and saving the data to a file and suddenly I was disconnected in the internet, will these catch exceptions below can really catch that kind of incident? If not, can you suggest how to handle this kind of incident? Note: I call this function in a thread so that the UI won't be blocked. public static boolean getFromRemote(String link, String fileName, Context context){ boolean dataReceived = false; ConnectivityManager connec = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE); if (connec.getNetworkInfo(0).isConnected() || connec.getNetworkInfo(1).isConnected()){ try { HttpClient httpClient = new DefaultHttpClient(); HttpGet httpGet = new HttpGet(link); HttpParams params = httpClient.getParams(); HttpConnectionParams.setConnectionTimeout(params, 30000); HttpConnectionParams.setSoTimeout(params, 30000); HttpResponse response; response = httpClient.execute(httpGet); int statusCode = response.getStatusLine().getStatusCode(); if (statusCode == 200){ HttpEntity entity = response.getEntity(); InputStream in = null; OutputStream output = null; try{ in = entity.getContent(); String secondLevelCacheDir = context.getCacheDir() + fileName; File imageFile = new File(secondLevelCacheDir); output= new FileOutputStream(imageFile); IOUtilities.copy(in, output); output.flush(); } catch (IOException e) { Log.e("SAVING", "Could not load xml", e); } finally { IOUtilities.closeStream(in); IOUtilities.closeStream(output); dataReceived = true; } } }catch (SocketTimeoutException e){ //Handle not connecting to client !!!! Log.d("SocketTimeoutException Thrown", e.toString()); dataReceived = false; } catch (ClientProtocolException e) { //Handle not connecting to client !!!! Log.d("ClientProtocolException Thrown", e.toString()); dataReceived = false; }catch (MalformedURLException e) { // TODO Auto-generated catch block e.printStackTrace(); dataReceived = false; Log.d("MalformedURLException Thrown", e.toString()); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); dataReceived = false; Log.d("IOException Thrown", e.toString()); } } return dataReceived; }

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  • Beginner problem with posting data table to JsonResult

    - by ognjenb
    With this script I get data from JsonResult (GetDevicesTable) and put them to table ( id="OrderDevices") <script type="text/javascript"> $(document).ready(function() { $("#getDevices a").click(function() { var Id = $(this).attr("rel"); var rowToMove = $(this).closest("tr"); $.post("/ImportXML/GetDevicesTable", { Id: Id }, function(data) { if (data.success) { //remove row rowToMove.fadeOut(function() { $(this).remove() }); //add row to other table $("#OrderDevices").append("<tr><td>"+ data.DeviceId+ "</td><td>" + data.Id+ "</td><td>" + data.OrderId + "</td></tr>"); } else { alert(data.ErrorMsg); } }, "json"); }); }); <% using (Html.BeginForm()) {%> <table id="OrderDevices" class="data-table"> <tr> <th> DeviceId </th> <th> Id </th> <th> OrderId </th> </tr> </table> <p> <input type="submit" value="Submit" /> </p> <% } %> When click on Submit I need something like this: $(document).ready(function() { $("#submit").click(function() { var Id = $(this).attr("rel"); var DeviceId = $(this).attr(???); var OrderId = $(this).attr(???); var rowToMove = $(this).closest("tr"); $.post("/ImportXML/DevicesActions", { Id: Id, DeviceId:DeviceId, OrderId:OrderId }, function(data) { }, "json"); }); }); I have problem with this script because do not know how post data to this JsonResult: public JsonResult DevicesActions(int Id,int DeviceId,int OrderId) { orderdevice ord = new orderdevice(); ord.Id = Id; ord.OrderId = DeviceId; ord.DeviceId = OrderId; DBEntities.AddToorderdevice(ord); DBEntities.SaveChanges(); }

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  • Persistent (purely functional) Red-Black trees on disk performance

    - by Waneck
    I'm studying the best data structures to implement a simple open-source object temporal database, and currently I'm very fond of using Persistent Red-Black trees to do it. My main reasons for using persistent data structures is first of all to minimize the use of locks, so the database can be as parallel as possible. Also it will be easier to implement ACID transactions and even being able to abstract the database to work in parallel on a cluster of some kind. The great thing of this approach is that it makes possible implementing temporal databases almost for free. And this is something quite nice to have, specially for web and for data analysis (e.g. trends). All of this is very cool, but I'm a little suspicious about the overall performance of using a persistent data structure on disk. Even though there are some very fast disks available today, and all writes can be done asynchronously, so a response is always immediate, I don't want to build all application under a false premise, only to realize it isn't really a good way to do it. Here's my line of thought: - Since all writes are done asynchronously, and using a persistent data structure will enable not to invalidate the previous - and currently valid - structure, the write time isn't really a bottleneck. - There are some literature on structures like this that are exactly for disk usage. But it seems to me that these techniques will add more read overhead to achieve faster writes. But I think that exactly the opposite is preferable. Also many of these techniques really do end up with a multi-versioned trees, but they aren't strictly immutable, which is something very crucial to justify the persistent overhead. - I know there still will have to be some kind of locking when appending values to the database, and I also know there should be a good garbage collecting logic if not all versions are to be maintained (otherwise the file size will surely rise dramatically). Also a delta compression system could be thought about. - Of all search trees structures, I really think Red-Blacks are the most close to what I need, since they offer the least number of rotations. But there are some possible pitfalls along the way: - Asynchronous writes -could- affect applications that need the data in real time. But I don't think that is the case with web applications, most of the time. Also when real-time data is needed, another solutions could be devised, like a check-in/check-out system of specific data that will need to be worked on a more real-time manner. - Also they could lead to some commit conflicts, though I fail to think of a good example of when it could happen. Also commit conflicts can occur in normal RDBMS, if two threads are working with the same data, right? - The overhead of having an immutable interface like this will grow exponentially and everything is doomed to fail soon, so this all is a bad idea. Any thoughts? Thanks! edit: There seems to be a misunderstanding of what a persistent data structure is: http://en.wikipedia.org/wiki/Persistent_data_structure

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  • how to check if internal storage file has any data

    - by user3720291
    public class Save extends Activity { int levels = 2; int data_block = 1024; //char[] data = new char[] {'0', '0'}; String blankval = "0"; String targetval = "0"; String temp; String tempwrite; String string = "null"; TextView tex1; TextView tex2; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.save); Intent intent = getIntent(); Bundle b = intent.getExtras(); tex1 = (TextView) findViewById(R.id.textView1); tex2 = (TextView) findViewById(R.id.textView2); if(b!=null) { string =(String) b.get("string"); } loadprev(); save(); } public void save() { if (string.equals("Blank")) blankval = "1"; if (string.equals("Target")) targetval = "1"; temp = blankval + targetval; try { FileOutputStream fos = openFileOutput("data.gds", MODE_PRIVATE); fos.write(temp.getBytes()); fos.close(); } catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} tex1.setText(blankval); tex2.setText(targetval); } public void loadprev() { String final_data = ""; try { FileInputStream fis = openFileInput("data.gds"); InputStreamReader isr = new InputStreamReader(fis); char[] data = new char[data_block]; int size; while((size = isr.read(data))>0) { String read_data = String.copyValueOf(data, 0, size); final_data += read_data; data = new char[data_block]; } } catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} char[] tempread = final_data.toCharArray();; blankval = "" + tempread[0]; targetval = "" + tempread[1]; } } After much tinkering i have finally managed to get my save/load function to work, but it does have an error, pretty much i got it to work then i did a fresh reintall deleting data.gds, afterwards the save/load function crashes because the data.gds file has no previous values. can i use a if statment to check if data.gds has any values in it, if so how do i do it and if not, then what could i use instead?

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  • Programmatically import CSV data to Access

    - by FrustratedWithFormsDesigner
    I have an Access database and the source of data comes from generated CSV files. I'd like to have an easy way for the users to simply select the data file and import it. Import should append the existing data to the data already in the data table. Is there a way in Access to create a file selector and import using saved CSV import settings that are already in the file?

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