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  • sqlite - any improvements for this attach code (running multiple sql commands transactionally in sql

    - by Greg
    Hi, Is this code solid? I've tried to use "using" etc. Basically a method to pass as sequenced list of SQL commands to be run against a Sqlite database. I assume it is true that in sqlite by default all commands run in a single connection are handled transactionally? Is this true? i.e. I should not have to (and haven't got in the code at the moment) a BeginTransaction, or CommitTransaction. It's using http://sqlite.phxsoftware.com/ as the sqlite ADO.net database provider. private int ExecuteNonQueryTransactionally(List<string> sqlList) { int totalRowsUpdated = 0; using (var conn = new SQLiteConnection(_connectionString)) { // Open connection (one connection so should be transactional - confirm) conn.Open(); // Apply each SQL statement passed in to sqlList foreach (string s in sqlList) { using (var cmd = new SQLiteCommand(conn)) { cmd.CommandText = s; totalRowsUpdated = totalRowsUpdated + cmd.ExecuteNonQuery(); } } } return totalRowsUpdated; }

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  • Populate data Crystal Report from a query

    - by Selom
    hi big bro and sis, Im having a problem with how to display data using crystal report programmatically and need your help. Im using vb.net for my project. I have a form that I called reportFrm on which I put the CrystalReportViewer1. I also added the CrystalReport1.rpt to my project and the CrystalReport1.rpt contains a textbox called firstname. i would like that when the reportFrm loads, it makes the following query and to fetch the firstname and put it in the textbox firstname: query: Dim cmd As New SQLiteCommand("SELECT * FROM personal_details JOIN studies USING staff_ID WHERE staff_ID = '" + detailsFrm.Label13.Text + "'", conn) my problem is that Im fetching data from two different tables and I don't how to do this. Thanks for helping

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  • SQLITE problem in rowid

    - by Saurabh
    I am using SQLite C# library and as per my requirement, before going to add I am retreving the rowid of that table. It is working fine but hetting error when table is empty. Once we add any data(a row) then it’s working fine . mDbCon = GetConnection(); SQLiteCommand cmd = mDbCon.CreateCommand(); cmd.CommandText = " SELECT MAX(rowid) FROM " + “MYTABLE”; cmd.CommandType = CommandType.Text; mDbCon.Open(); SQLiteDataReader sqReader = cmd.ExecuteReader(); while (sqReader.Read()) { if ( sqReader.IsDBNull(0) ) { max = (Int32)sqReader.GetInt32(0); } } mDbCon.Close(); It’s throwing exception when table “MYTABLE” don’t have any data.

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  • Database file is inexplicably locked during SQLite commit

    - by sweeney
    Hello, I'm performing a large number of INSERTS to a SQLite database. I'm using just one thread. I batch the writes to improve performance and have a bit of security in case of a crash. Basically I cache up a bunch of data in memory and then when I deem appropriate, I loop over all of that data and perform the INSERTS. The code for this is shown below: public void Commit() { using (SQLiteConnection conn = new SQLiteConnection(this.connString)) { conn.Open(); using (SQLiteTransaction trans = conn.BeginTransaction()) { using (SQLiteCommand command = conn.CreateCommand()) { command.CommandText = "INSERT OR IGNORE INTO [MY_TABLE] (col1, col2) VALUES (?,?)"; command.Parameters.Add(this.col1Param); command.Parameters.Add(this.col2Param); foreach (Data o in this.dataTemp) { this.col1Param.Value = o.Col1Prop; this. col2Param.Value = o.Col2Prop; command.ExecuteNonQuery(); } } this.TryHandleCommit(trans); } conn.Close(); } } I now employ the following gimmick to get the thing to eventually work: private void TryHandleCommit(SQLiteTransaction trans) { try { trans.Commit(); } catch (Exception e) { Console.WriteLine("Trying again..."); this.TryHandleCommit(trans); } } I create my DB like so: public DataBase(String path) { //build connection string SQLiteConnectionStringBuilder connString = new SQLiteConnectionStringBuilder(); connString.DataSource = path; connString.Version = 3; connString.DefaultTimeout = 5; connString.JournalMode = SQLiteJournalModeEnum.Persist; connString.UseUTF16Encoding = true; using (connection = new SQLiteConnection(connString.ToString())) { //check for existence of db FileInfo f = new FileInfo(path); if (!f.Exists) //build new blank db { SQLiteConnection.CreateFile(path); connection.Open(); using (SQLiteTransaction trans = connection.BeginTransaction()) { using (SQLiteCommand command = connection.CreateCommand()) { command.CommandText = DataBase.CREATE_MATCHES; command.ExecuteNonQuery(); command.CommandText = DataBase.CREATE_STRING_DATA; command.ExecuteNonQuery(); //TODO add logging } trans.Commit(); } connection.Close(); } } } I then export the connection string and use it to obtain new connections in different parts of the program. At seemingly random intervals, though at far too great a rate to ignore or otherwise workaround this problem, I get unhandled SQLiteException: Database file is locked. This occurs when I attempt to commit the transaction. No errors seem to occur prior to then. This does not always happen. Sometimes the whole thing runs without a hitch. No reads are being performed on these files before the commits finish. I have the very latest SQLite binary. I'm compiling for .NET 2.0. I'm using VS 2008. The db is a local file. All of this activity is encapsulated within one thread / process. Virus protection is off (though I think that was only relevant if you were connecting over a network?). As per Scotsman's post I have implemented the following changes: Journal Mode set to Persist DB files stored in C:\Docs + Settings\ApplicationData via System.Windows.Forms.Application.AppData windows call No inner exception Witnessed on two distinct machines (albeit very similar hardware and software) Have been running Process Monitor - no extraneous processes are attaching themselves to the DB files - the problem is definitely in my code... Does anyone have any idea whats going on here? I know I just dropped a whole mess of code, but I've been trying to figure this out for way too long. My thanks to anyone who makes it to the end of this question! brian UPDATES: Thanks for the suggestions so far! I've implemented many of the suggested changes. I feel that we are getting closer to the answer...however... The code above technically works however it is non-deterministic! It is not guaranteed to do anything aside from spin in neutral forever. In practice it seems to work somewhere between the 1st and 10th iteration. If i batch my commits at a reasonable interval damage will be mitigated but I really do not want to leave things in this state... More suggestions welcome!

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  • SQLite Transaction fills a table BEFORE the transaction is commited

    - by user1500403
    Halo I have a code that creates a datatable (in memory) from a select SQL statement. However I realised that this datatable is filling during the procedure rather as a result of the transaction comit statment, it does the job but its slow. WHat amI doing wrong ? Inalready.Clear() 'clears a dictionary Using connection As New SQLite.SQLiteConnection(conectionString) connection.Open() Dim sqliteTran As SQLite.SQLiteTransaction = connection.BeginTransaction() Try oMainQueryR = "SELECT * FROM detailstable Where name= :name AND Breed= :Breed" Dim cmdSQLite As SQLite.SQLiteCommand = connection.CreateCommand() Dim oAdapter As New SQLite.SQLiteDataAdapter(cmdSQLite) With cmdSQLite .CommandType = CommandType.Text .CommandText = oMainQueryR .Parameters.Add(":name", SqlDbType.VarChar) .Parameters.Add(":Breed", SqlDbType.VarChar) End With Dim c As Long = 0 For Each row As DataRow In list.Rows 'this is the list with 500 names If Inalready.ContainsKey(row.Item("name")) Then Else c = c + 1 Form1.TextBox1.Text = " Fill .... " & c Application.DoEvents() Inalready.Add(row.Item("name"), row.Item("Breed")) cmdSQLite.Parameters(":name").Value = row.Item("name") cmdSQLite.Parameters(":Breed").Value = row.Item("Breed") oAdapter.Fill(newdetailstable) End If Next oAdapter.FillSchema(newdetailstable, SchemaType.Source) Dim z = newdetailstable.Rows.Count 'At this point the newdetailstable is already filled up and I havent even comited the transaction ' sqliteTran.Commit() Catch ex As Exception End Try End Using

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  • SQLITE - INSERT does not return error but no data is inserted.

    - by Nick
    I am attempting to insert data into a local SQLITE database file from a C# application. The transaction does not throw any errors but the data is not inserted. The same insert statement works from within a query analyzer. Do I need to perform a commit? Is there a Commit method? Command's transaction property is null.. var command = new SQLiteCommand(insert.BuildInsert(tableName,keyValuePairs),Connection); command.ExecuteNonQuery();

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  • StackOverflow in VB.NET SQLite query

    - by Majgel
    I have an StackOverflowException in one of my DB functions that I don't know how to deal with. I have a SQLite database with one table "tblEmployees" that holds records for each employees (several thousand posts) and usually this function runs without any problem. But sometimes after the the function is called a thousand times it breaks with an StackOverflowException at the line "ReturnTable.Load(reader)" with the message: An unhandled exception of type 'System.StackOverflowException' occurred in System.Data.SQLite.dll If I restart the application it has no problem to continue with the exact same post it last crashed on. I can also make the exactly same DB-call from SQLite Admin at the crash time without no problems. Here is the code: Public Function GetNextEmployeeInQueue() As String Dim NextEmployeeInQueue As String = Nothing Dim query As [String] = "SELECT FirstName FROM tblEmployees WHERE Checked=0 LIMIT 1;" Try Dim ReturnTable As New DataTable() Dim mycommand As New SQLiteCommand(cnn) mycommand.CommandText = query Dim reader As SQLiteDataReader = mycommand.ExecuteReader() ReturnTable.Load(reader) reader.Close() If ReturnTable.Rows.Count > 0 Then NextEmployeeInQueue = ReturnTable.Rows(0)("FirstName").ToString() Else MsgBox("No more employees found in queue") End If Catch fail As Exception MessageBox.Show("Error: " & fail.Message.ToString()) End Try If NextEmployeeInQueue IsNot Nothing Then Return NextEmployeeInQueue Else Return "No more records in queue" End If End Function When crashes, the reader has "Property evaluation failed." in all values. I assume there is some problem with allocated memory that isn't released correctly, but can't figure out what object it's all about. The DB-connection opens when the DB-class object is created and closes on main form Dispose. Should I maybe dispose the mycommand object every time in a finally block? But wouldn't that result in a closed DB-connection?

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  • Make a Crystal Report with data fetched from two differents tables

    - by Selom
    Hi, Im using vb.net and I need to fetch data from two different tables and display it in form of report. These are the schemas and data of my two tables: CREATE TABLE personal_details (staff_ID integer PRIMARY KEY, title varchar(10), fn varchar(250), ln varchar(250), mn varchar(250), dob varchar(50), hometown varchar(250), securityno varchar(50), phone varchar(15), phone2 varchar(15), phone3 varchar(15), email varchar(250), address varchar(300), confirmation varchar(50), retirement varchar(50), designation varchar(250), region varchar(250)); INSERT INTO personal_details VALUES(1,'Mr.','Selom','AMOUZOU','Kokou','Sunday, March 28, 2010','Ho',7736,'024-747-4883','277-383-8383','027-838-3837','[email protected]','Lapaz Kum Hotel','Sunday, March 28, 2010','Sunday, March 28, 2010','Designeur','Brong Ahafo'); CREATE TABLE training( training_ID integer primary key NOT NULL, staff_ID varchar(100), training_level varchar (60), school_name varchar(100), start_date varchar(100), end_date varchar(100)); INSERT INTO training VALUES(1,1,'Primary School','New School','Feb 1955','May 1973'); INSERT INTO training VALUES(2,1,'Middle/JSS','Ipmc','Feb 1955','May 1973'); Im trying to fetch and display data from the tables above the following way: Dim rpt As New CrystalReport1() Dim da As New SQLiteDataAdapter Dim ds As New presbydbDataSet ds.EnforceConstraints = False If conn.State = ConnectionState.Closed Then conn.Open() End If Dim cmd As New SQLiteCommand("SELECT p.fn, t.training_level FROM personal_details p INNER JOIN training t ON p.staff_ID = t.staff_ID", conn) cmd.ExecuteNonQuery() da.SelectCommand = cmd da.Fill(ds) rpt.SetDataSource(ds) CrystalReportViewer1.ReportSource = rpt conn.Close() My problem is that nothing displays on the report unless I take off either the training fields or the personal_details fields from the report. Need your help. Thanks

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  • vb.net sqlite how to loop through selected records and pass each record as a parameter to another fu

    - by mazrabul
    Hi, I have a sqlite table with following fields: Langauge level hours German 2 50 French 3 40 English 1 60 German 1 10 English 2 50 English 3 60 German 1 20 French 2 40 I want to loop through the records based on language and other conditions and then pass the current selected record to a different function. So I have the following mixture of actual code and psudo code. I need help with converting the psudo code to actual code, please. I am finding it difficult to do so. Here is what I have: Private sub mainp() Dim oslcConnection As New SQLite.SQLiteConnection Dim oslcCommand As SQLite.SQLiteCommand Dim langs() As String = {"German", "French", "English"} Dim i as Integer = 0 oslcConnection.ConnectionString = "Data Source=" & My.Settings.dbFullPath & ";" oslcConnection.Open() oslcCommand = oslcConnection.CreateCommand Do While i <= langs.count If langs(i) = "German" Then oslcCommand.CommandText = "SELECT * FROM table WHERE language = '" & langs(i) & "';" For each record selected 'psudo code If level = 1 Then 'psudo code update level to 2 'psudo code minorp(currentRecord) 'psudo code: calling minorp function and passing the whole record as a parameter End If 'psudo code If level = 2 Then 'psudo code update level to 3 'psudo code minorp(currentRecord) 'psudo code: calling minorp function and passing the whole record as a parameter End If 'psudo code Next 'psudo code End If If langs(i) = "French" Then oslcCommand.CommandText = "SELECT * FROM table WHERE language = '" & langs(i) & "';" For each record selected 'psudo code If level = 1 Then 'psudo code update level to 2 'psudo code minorp(currentRecord) 'psudo code: calling minorp function and passing the whole record as a parameter End If 'psudo code If level = 2 Then 'psudo code update level to 3 'psudo code minorp(currentRecord) 'psudo code: calling minorp function and passing the whole record as a parameter End If 'psudo code Next 'psudo code End If Loop End Sub Many thanks for your help.

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  • C# sqlite syntax in ASP.NET?

    - by acidzombie24
    -edit- This is no longer relevant and the question doesnt make sense to me anymore. I think i wanted to know how to create tables or know if the syntax is the same from winform to ASP.NET I am very use to sqlite http://sqlite.phxsoftware.com/ and would like to create a DB in a similar style. How do i do this? it doesnt need to be the same, just similar enough for me to enjoy. An example of the syntax. connection = new SQLiteConnection("Data Source=" + sz +";Version=3"); command = new SQLiteCommand(connection); connection.Open(); command.CommandText = "CREATE TABLE if not exists miscInfo(key TEXT, " + "value TEXT, UNIQUE (key));"; command.ExecuteNonQuery(); The @name is a symbol and command.Parameters.Add("@userDesc", DbType.String).Value = d.userDesc; replaces the symbol with escaped values/texts/blob command.CommandText = "INSERT INTO discData(rootfolderID, time, volumeName, discLabel, " + "userTitle, userDesc) "+ "VALUES(@rootfolderID, @time, @volumeName, @discLabel, " + "@userTitle, @userDesc); " + "SELECT last_insert_rowid() AS RecordID;"; command.Parameters.Add("@rootfolderID", DbType.Int64).Value = d.rootfolderID; command.Parameters.Add("@time", DbType.Int64).Value = d.time; command.Parameters.Add("@volumeName", DbType.String).Value = d.volumeName; command.Parameters.Add("@discLabel", DbType.String).Value = d.discLabel; command.Parameters.Add("@userTitle", DbType.String).Value = d.userTitle; command.Parameters.Add("@userDesc", DbType.String).Value = d.userDesc; d.discID = (long)command.ExecuteScalar();

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  • System.Data.SQLite parameter issue

    - by CasperT
    I have the following code: try { //Create connection SQLiteConnection conn = DBConnection.OpenDB(); //Verify user input, normally you give dbType a size, but Text is an exception var uNavnParam = new SQLiteParameter("@uNavnParam", SqlDbType.Text) { Value = uNavn }; var bNavnParam = new SQLiteParameter("@bNavnParam", SqlDbType.Text) { Value = bNavn }; var passwdParam = new SQLiteParameter("@passwdParam", SqlDbType.Text) {Value = passwd}; var pc_idParam = new SQLiteParameter("@pc_idParam", SqlDbType.TinyInt) { Value = pc_id }; var noterParam = new SQLiteParameter("@noterParam", SqlDbType.Text) { Value = noter }; var licens_idParam = new SQLiteParameter("@licens_idParam", SqlDbType.TinyInt) { Value = licens_id }; var insertSQL = new SQLiteCommand("INSERT INTO Brugere (navn, brugernavn, password, pc_id, noter, licens_id)" + "VALUES ('@uNameParam', '@bNavnParam', '@passwdParam', '@pc_idParam', '@noterParam', '@licens_idParam')", conn); insertSQL.Parameters.Add(uNavnParam); //replace paramenter with verified userinput insertSQL.Parameters.Add(bNavnParam); insertSQL.Parameters.Add(passwdParam); insertSQL.Parameters.Add(pc_idParam); insertSQL.Parameters.Add(noterParam); insertSQL.Parameters.Add(licens_idParam); insertSQL.ExecuteNonQuery(); //Execute query //Close connection DBConnection.CloseDB(conn); //Let the user know that it was changed succesfully this.Text = "Succes! Changed!"; } catch(SQLiteException e) { //Catch error MessageBox.Show(e.ToString(), "ALARM"); } It executes perfectly, but when I view my "brugere" table, it has inserted the values: '@uNameParam', '@bNavnParam', '@passwdParam', '@pc_idParam', '@noterParam', '@licens_idParam' literally. Instead of replacing them. I have tried making a breakpoint and checked the parameters, they do have the correct assigned values. So that is not the issue either. I have been tinkering with this a lot now, with no luck, can anyone help? Oh and for reference, here is the OpenDB method from the DBConnection class: public static SQLiteConnection OpenDB() { try { //Gets connectionstring from app.config const string myConnectString = "data source=data;"; var conn = new SQLiteConnection(myConnectString); conn.Open(); return conn; } catch (SQLiteException e) { MessageBox.Show(e.ToString(), "ALARM"); return null; } }

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