// If it's an Insert we fetch the @@Identity value and stuff it in the proper column
protected void OnRowUpdated(object sender, VistaDBRowUpdatedEventArgs e)
{
try
{
if (e.Status == UpdateStatus.Continue && e.StatementType == StatementType.Insert)
{
TransactionMgr txMgr = TransactionMgr.ThreadTransactionMgr();
string[] identityCols = this.GetAutoKeyColumns().Split(';');
VistaDBCommand cmd = new VistaDBCommand();
foreach (string col in identityCols)
{
cmd.CommandText = "SELECT LastIdentity([" + col + "]) FROM [" + this.QuerySource + "]";
// We make sure we enlist in the ongoing transaction, otherwise, we
// would most likely deadlock
txMgr.Enlist(cmd, this);
object o = cmd.ExecuteScalar(); // Get the Identity Value
txMgr.DeEnlist(cmd, this);
if (o != null)
{
e.Row[col] = o;
}
}
e.Row.AcceptChanges();
}
}
catch {}
}
public static object executeScalar(this API_VistaDB vistaDB, string command)
{
"[API_VistaDB] Executing Scalar: {0}".info(command);
VistaDBConnection sqlConnection = null;
try
{
sqlConnection = new VistaDBConnection(vistaDB.ConnectionString);
sqlConnection.Open();
var sqlCommand = new VistaDBCommand();
sqlCommand.Connection = sqlConnection;
sqlCommand.CommandText = command;
sqlCommand.CommandType = CommandType.Text;
return(sqlCommand.ExecuteScalar());
}
catch (Exception ex)
{
vistaDB.LastError = ex.Message;
"[executeNonQuery] {0}".error(ex.Message);
//ex.log();
}
finally
{
sqlConnection.Close();
}
return(null);
}
public Object ExecuteScalar(String sql)
{
VistaDBCommand cmd = new VistaDBCommand(sql, co);
Object o = null;
try
{
o = cmd.ExecuteScalar();
_lastError = "";
}
catch (Exception e)
{
_lastError = e.Message;
}
return(o);
}
/// <summary>
/// 同步文件
/// </summary>
/// <param name="currentFile">The current file.</param>
public void SynFileInfo(FileInfo currentFile)
{
//检查项目中是否存在该文件(目录+文件名)
//比较文件：是否更新？
string sql = string.Format("select top 1 FileID from [FileSystem] where ProjectID={0} AND FileDir='{1}' AND FileName='{2}'",
1,
currentFile.DirectoryName.Replace(BaseDir, "").Replace("\\", "/"),
currentFile.Name);
VistaDBCommand cmd = new VistaDBCommand(sql, conn);
object oFileID = cmd.ExecuteScalar();
if (oFileID == null)
{
PackageFile(currentFile);
}
else
{
#region 比较版本
#endregion
#region 插入新文件
sql = "insert into [FileSystem](FileName,FileDir,FileSize,HashCode,BinData,FileVersion,CreateDate,LastChangeDate) values("
+ "@FileName,@FileDir,@FileSize,@HashCode,@BinData,2, @CreateDate, @LastChangeDate"
+ ")";
VistaDBCommand cmdAdd = new VistaDBCommand(sql, conn);
cmd.Parameters.AddWithValue("@FileName", currentFile.Name);
cmd.Parameters.AddWithValue("@FileDir", currentFile.DirectoryName.Replace(BaseDir, "").Replace("\\", "/"));
cmd.Parameters.AddWithValue("@FileSize", currentFile.Length);
byte[] fBin = InitialProject.GetFileBytes(currentFile.FullName);
cmd.Parameters.AddWithValue("@HashCode", InitialProject.GetMD5Hash(fBin));
cmd.Parameters.AddWithValue("@BinData", fBin);
cmd.Parameters.AddWithValue("@CreateDate", currentFile.CreationTimeUtc);
cmd.Parameters.AddWithValue("@LastChangeDate", currentFile.LastWriteTimeUtc);
cmd.ExecuteNonQuery();
cmd.Dispose();
#endregion
}
}
/// <summary>
/// Logs an error to the database.
/// </summary>
/// <remarks>
/// Use the stored procedure called by this implementation to set a
/// policy on how long errors are kept in the log. The default
/// implementation stores all errors for an indefinite time.
/// </remarks>
public override string Log(Error error)
{
if (error == null)
{
throw new ArgumentNullException("error");
}
string errorXml = ErrorXml.EncodeString(error);
using (VistaDBConnection connection = new VistaDBConnection(this.ConnectionString))
using (VistaDBCommand command = connection.CreateCommand())
{
connection.Open();
command.CommandText = @"INSERT INTO ELMAH_Error
(Application, Host, Type, Source,
Message, [User], AllXml, StatusCode, TimeUtc)
VALUES
(@Application, @Host, @Type, @Source,
@Message, @User, @AllXml, @StatusCode, @TimeUtc);
SELECT @@IDENTITY";
command.CommandType = CommandType.Text;
VistaDBParameterCollection parameters = command.Parameters;
parameters.Add("@Application", VistaDBType.NVarChar, _maxAppNameLength).Value = ApplicationName;
parameters.Add("@Host", VistaDBType.NVarChar, 30).Value = error.HostName;
parameters.Add("@Type", VistaDBType.NVarChar, 100).Value = error.Type;
parameters.Add("@Source", VistaDBType.NVarChar, 60).Value = error.Source;
parameters.Add("@Message", VistaDBType.NVarChar, 500).Value = error.Message;
parameters.Add("@User", VistaDBType.NVarChar, 50).Value = error.User;
parameters.Add("@AllXml", VistaDBType.NText).Value = errorXml;
parameters.Add("@StatusCode", VistaDBType.Int).Value = error.StatusCode;
parameters.Add("@TimeUtc", VistaDBType.DateTime).Value = error.Time.ToUniversalTime();
return(Convert.ToString(command.ExecuteScalar(), CultureInfo.InvariantCulture));
}
}
esDataResponse IDataProvider.ExecuteScalar(esDataRequest request)
{
esDataResponse response = new esDataResponse();
VistaDBCommand cmd = null;
try
{
cmd = new VistaDBCommand();
if (request.CommandTimeout != null)
{
cmd.CommandTimeout = request.CommandTimeout.Value;
}
if (request.Parameters != null)
{
Shared.AddParameters(cmd, request);
}
switch (request.QueryType)
{
case esQueryType.TableDirect:
cmd.CommandType = CommandType.TableDirect;
cmd.CommandText = request.QueryText;
break;
case esQueryType.StoredProcedure:
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = Shared.CreateFullName(request);
break;
case esQueryType.Text:
cmd.CommandType = CommandType.Text;
cmd.CommandText = request.QueryText;
break;
case esQueryType.DynamicQuery:
cmd = QueryBuilder.PrepareCommand(request);
break;
}
try
{
esTransactionScope.Enlist(cmd, request.ConnectionString, CreateIDbConnectionDelegate);
response.Scalar = cmd.ExecuteScalar();
}
finally
{
esTransactionScope.DeEnlist(cmd);
}
if (request.Parameters != null)
{
Shared.GatherReturnParameters(cmd, request, response);
}
}
catch (Exception ex)
{
CleanupCommand(cmd);
response.Exception = ex;
}
return(response);
}
protected static void OnRowUpdated(object sender, VistaDBRowUpdatedEventArgs e)
{
try
{
PropertyCollection props = e.Row.Table.ExtendedProperties;
if (props.ContainsKey("props"))
{
props = (PropertyCollection)props["props"];
}
if (e.Status == UpdateStatus.Continue && (e.StatementType == StatementType.Insert || e.StatementType == StatementType.Update))
{
esDataRequest request = props["esDataRequest"] as esDataRequest;
esEntitySavePacket packet = (esEntitySavePacket)props["esEntityData"];
string source = props["Source"] as string;
if (e.StatementType == StatementType.Insert)
{
if (props.Contains("AutoInc"))
{
string autoInc = props["AutoInc"] as string;
VistaDBCommand cmd = new VistaDBCommand();
cmd.Connection = e.Command.Connection;
cmd.Transaction = e.Command.Transaction;
cmd.CommandText = "SELECT LastIdentity([" + autoInc + "]) FROM [" + source + "]";
object o = null;
o = cmd.ExecuteScalar();
if (o != null)
{
e.Row[autoInc] = o;
e.Command.Parameters["@" + autoInc].Value = o;
}
}
if (props.Contains("EntitySpacesConcurrency"))
{
string esConcurrencyColumn = props["EntitySpacesConcurrency"] as string;
packet.CurrentValues[esConcurrencyColumn] = 1;
}
}
if (props.Contains("Timestamp"))
{
string column = props["Timestamp"] as string;
VistaDBCommand cmd = new VistaDBCommand();
cmd.Connection = e.Command.Connection;
cmd.Transaction = e.Command.Transaction;
cmd.CommandText = "SELECT LastTimestamp('" + source + "');";
object o = null;
o = cmd.ExecuteScalar();
if (o != null)
{
e.Command.Parameters["@" + column].Value = o;
}
}
//-------------------------------------------------------------------------------------------------
// Fetch any defaults, SQLite doesn't support output parameters so we gotta do this the hard way
//-------------------------------------------------------------------------------------------------
if (props.Contains("Defaults"))
{
// Build the Where parameter and parameters
VistaDBCommand cmd = new VistaDBCommand();
cmd.Connection = e.Command.Connection;
cmd.Transaction = e.Command.Transaction;
string select = (string)props["Defaults"];
string[] whereParameters = ((string)props["Where"]).Split(',');
string comma = String.Empty;
string where = String.Empty;
int i = 1;
foreach (string parameter in whereParameters)
{
VistaDBParameter p = new VistaDBParameter("@p" + i++.ToString(), e.Row[parameter]);
cmd.Parameters.Add(p);
where += comma + "[" + parameter + "]=" + p.ParameterName;
comma = " AND ";
}
// Okay, now we can execute the sql and get any values that have defaults that were
// null at the time of the insert and/or our timestamp
cmd.CommandText = "SELECT " + select + " FROM [" + request.ProviderMetadata.Source + "] WHERE " + where + ";";
VistaDBDataReader rdr = null;
try
{
rdr = cmd.ExecuteReader(CommandBehavior.SingleResult);
if (rdr.Read())
{
select = select.Replace("[", String.Empty).Replace("]", String.Empty);
string[] selectCols = select.Split(',');
for (int k = 0; k < selectCols.Length; k++)
{
packet.CurrentValues[selectCols[k]] = rdr.GetValue(k);
}
}
}
finally
{
// Make sure we close the reader no matter what
if (rdr != null)
{
rdr.Close();
}
}
}
if (e.StatementType == StatementType.Update)
{
string colName = props["EntitySpacesConcurrency"] as string;
object o = e.Row[colName];
VistaDBParameter p = e.Command.Parameters["@" + colName];
object v = null;
switch (Type.GetTypeCode(o.GetType()))
{
case TypeCode.Int16: v = ((System.Int16)o) + 1; break;
case TypeCode.Int32: v = ((System.Int32)o) + 1; break;
case TypeCode.Int64: v = ((System.Int64)o) + 1; break;
case TypeCode.UInt16: v = ((System.UInt16)o) + 1; break;
case TypeCode.UInt32: v = ((System.UInt32)o) + 1; break;
case TypeCode.UInt64: v = ((System.UInt64)o) + 1; break;
}
p.Value = v;
}
}
}
catch { }
}
protected static void OnRowUpdated(object sender, VistaDBRowUpdatedEventArgs e)
{
try
{
PropertyCollection props = e.Row.Table.ExtendedProperties;
if (props.ContainsKey("props"))
{
props = (PropertyCollection)props["props"];
}
if (e.Status == UpdateStatus.Continue && (e.StatementType == StatementType.Insert || e.StatementType == StatementType.Update))
{
tgDataRequest request = props["tgDataRequest"] as tgDataRequest;
tgEntitySavePacket packet = (tgEntitySavePacket)props["esEntityData"];
string source = props["Source"] as string;
if (e.StatementType == StatementType.Insert)
{
if (props.Contains("AutoInc"))
{
string autoInc = props["AutoInc"] as string;
VistaDBCommand cmd = new VistaDBCommand();
cmd.Connection = e.Command.Connection;
cmd.Transaction = e.Command.Transaction;
cmd.CommandText = "SELECT LastIdentity([" + autoInc + "]) FROM [" + source + "]";
object o = null;
#region Profiling
if (sTraceHandler != null)
{
using (esTraceArguments esTrace = new esTraceArguments(request, cmd, "OnRowUpdated", System.Environment.StackTrace))
{
try
{
o = cmd.ExecuteScalar();
}
catch (Exception ex)
{
esTrace.Exception = ex.Message;
throw;
}
}
}
else
#endregion Profiling
{
o = cmd.ExecuteScalar();
}
if (o != null)
{
e.Row[autoInc] = o;
e.Command.Parameters["@" + autoInc].Value = o;
}
}
if (props.Contains("EntitySpacesConcurrency"))
{
string esConcurrencyColumn = props["EntitySpacesConcurrency"] as string;
packet.CurrentValues[esConcurrencyColumn] = 1;
}
}
if (props.Contains("Timestamp"))
{
string column = props["Timestamp"] as string;
VistaDBCommand cmd = new VistaDBCommand();
cmd.Connection = e.Command.Connection;
cmd.Transaction = e.Command.Transaction;
cmd.CommandText = "SELECT LastTimestamp('" + source + "');";
object o = null;
#region Profiling
if (sTraceHandler != null)
{
using (esTraceArguments esTrace = new esTraceArguments(request, cmd, "OnRowUpdated", System.Environment.StackTrace))
{
try
{
o = cmd.ExecuteScalar();
}
catch (Exception ex)
{
esTrace.Exception = ex.Message;
throw;
}
}
}
else
#endregion Profiling
{
o = cmd.ExecuteScalar();
}
if (o != null)
{
e.Command.Parameters["@" + column].Value = o;
}
}
//-------------------------------------------------------------------------------------------------
// Fetch any defaults, SQLite doesn't support output parameters so we gotta do this the hard way
//-------------------------------------------------------------------------------------------------
if (props.Contains("Defaults"))
{
// Build the Where parameter and parameters
VistaDBCommand cmd = new VistaDBCommand();
cmd.Connection = e.Command.Connection;
cmd.Transaction = e.Command.Transaction;
string select = (string)props["Defaults"];
string[] whereParameters = ((string)props["Where"]).Split(',');
string comma = String.Empty;
string where = String.Empty;
int i = 1;
foreach (string parameter in whereParameters)
{
VistaDBParameter p = new VistaDBParameter("@p" + i++.ToString(), e.Row[parameter]);
cmd.Parameters.Add(p);
where += comma + "[" + parameter + "]=" + p.ParameterName;
comma = " AND ";
}
// Okay, now we can execute the sql and get any values that have defaults that were
// null at the time of the insert and/or our timestamp
cmd.CommandText = "SELECT " + select + " FROM [" + request.ProviderMetadata.Source + "] WHERE " + where + ";";
VistaDBDataReader rdr = null;
try
{
#region Profiling
if (sTraceHandler != null)
{
using (esTraceArguments esTrace = new esTraceArguments(request, cmd, "OnRowUpdated", System.Environment.StackTrace))
{
try
{
rdr = cmd.ExecuteReader(CommandBehavior.SingleResult);
}
catch (Exception ex)
{
esTrace.Exception = ex.Message;
throw;
}
}
}
else
#endregion Profiling
{
rdr = cmd.ExecuteReader(CommandBehavior.SingleResult);
}
if (rdr.Read())
{
select = select.Replace("[", String.Empty).Replace("]", String.Empty);
string[] selectCols = select.Split(',');
for (int k = 0; k < selectCols.Length; k++)
{
packet.CurrentValues[selectCols[k]] = rdr.GetValue(k);
}
}
}
finally
{
// Make sure we close the reader no matter what
if (rdr != null) rdr.Close();
}
}
if (e.StatementType == StatementType.Update)
{
string colName = props["EntitySpacesConcurrency"] as string;
object o = e.Row[colName];
VistaDBParameter p = e.Command.Parameters["@" + colName];
object v = null;
switch (Type.GetTypeCode(o.GetType()))
{
case TypeCode.Int16: v = ((System.Int16)o) + 1; break;
case TypeCode.Int32: v = ((System.Int32)o) + 1; break;
case TypeCode.Int64: v = ((System.Int64)o) + 1; break;
case TypeCode.UInt16: v = ((System.UInt16)o) + 1; break;
case TypeCode.UInt32: v = ((System.UInt32)o) + 1; break;
case TypeCode.UInt64: v = ((System.UInt64)o) + 1; break;
}
p.Value = v;
}
}
}
catch { }
}
tgDataResponse IDataProvider.ExecuteScalar(tgDataRequest request)
{
tgDataResponse response = new tgDataResponse();
VistaDBCommand cmd = null;
try
{
cmd = new VistaDBCommand();
if (request.CommandTimeout != null) cmd.CommandTimeout = request.CommandTimeout.Value;
if (request.Parameters != null) Shared.AddParameters(cmd, request);
switch (request.QueryType)
{
case tgQueryType.TableDirect:
cmd.CommandType = CommandType.TableDirect;
cmd.CommandText = request.QueryText;
break;
case tgQueryType.StoredProcedure:
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = Shared.CreateFullName(request);
break;
case tgQueryType.Text:
cmd.CommandType = CommandType.Text;
cmd.CommandText = request.QueryText;
break;
case tgQueryType.DynamicQuery:
cmd = QueryBuilder.PrepareCommand(request);
break;
}
try
{
tgTransactionScope.Enlist(cmd, request.ConnectionString, CreateIDbConnectionDelegate);
#region Profiling
if (sTraceHandler != null)
{
using (esTraceArguments esTrace = new esTraceArguments(request, cmd, "ExecuteScalar", System.Environment.StackTrace))
{
try
{
response.Scalar = cmd.ExecuteScalar();
}
catch (Exception ex)
{
esTrace.Exception = ex.Message;
throw;
}
}
}
else
#endregion Profiling
{
response.Scalar = cmd.ExecuteScalar();
}
}
finally
{
tgTransactionScope.DeEnlist(cmd);
}
if (request.Parameters != null)
{
Shared.GatherReturnParameters(cmd, request, response);
}
}
catch (Exception ex)
{
CleanupCommand(cmd);
response.Exception = ex;
}
return response;
}
// If it's an Insert we fetch the @@Identity value and stuff it in the proper column
protected void OnRowUpdated(object sender, VistaDBRowUpdatedEventArgs e)
{
try
{
if(e.Status == UpdateStatus.Continue && e.StatementType == StatementType.Insert)
{
TransactionMgr txMgr = TransactionMgr.ThreadTransactionMgr();
string[] identityCols = this.GetAutoKeyColumns().Split(';');
VistaDBCommand cmd = new VistaDBCommand();
foreach(string col in identityCols)
{
cmd.CommandText = "SELECT LastIdentity([" + col + "]) FROM [" + this.QuerySource + "]";
// We make sure we enlist in the ongoing transaction, otherwise, we
// would most likely deadlock
txMgr.Enlist(cmd, this);
object o = cmd.ExecuteScalar(); // Get the Identity Value
txMgr.DeEnlist(cmd, this);
if(o != null)
{
e.Row[col] = o;
}
}
e.Row.AcceptChanges();
}
}
catch {}
}
esDataResponse IDataProvider.ExecuteScalar(esDataRequest request)
{
esDataResponse response = new esDataResponse();
VistaDBCommand cmd = null;
try
{
cmd = new VistaDBCommand();
if (request.CommandTimeout != null) cmd.CommandTimeout = request.CommandTimeout.Value;
if (request.Parameters != null) Shared.AddParameters(cmd, request);
switch (request.QueryType)
{
case esQueryType.TableDirect:
cmd.CommandType = CommandType.TableDirect;
cmd.CommandText = request.QueryText;
break;
case esQueryType.StoredProcedure:
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = Shared.CreateFullName(request);
break;
case esQueryType.Text:
cmd.CommandType = CommandType.Text;
cmd.CommandText = request.QueryText;
break;
case esQueryType.DynamicQuery:
cmd = QueryBuilder.PrepareCommand(request);
break;
}
try
{
esTransactionScope.Enlist(cmd, request.ConnectionString, CreateIDbConnectionDelegate);
response.Scalar = cmd.ExecuteScalar();
}
finally
{
esTransactionScope.DeEnlist(cmd);
}
if (request.Parameters != null)
{
Shared.GatherReturnParameters(cmd, request, response);
}
}
catch (Exception ex)
{
CleanupCommand(cmd);
response.Exception = ex;
}
return response;
}
public static string GetDatabaseVersionFunction()
{
try
{
//To open a SQL connection to VistaDB from within a CLR Proc you must set the connection string to Context connection=true like this....
//NOTE: We DO want to dispose of this object because we are the ones allocating it
using (VistaDBConnection conn = new VistaDBConnection("Context Connection=true"))
{
conn.Open();
using (VistaDBCommand command = new VistaDBCommand())
{
command.Connection = conn;
command.CommandText = "SELECT @@Version";
return Convert.ToString(command.ExecuteScalar());
}
}
}
catch (Exception e)
{
return e.Message;
}
}
public static int GetDatabaseVersionProcedure(out string versionString )
{
try
{
//To open a SQL connection to VistaDB from within a CLR Proc you must set the connection string to Context connection=true like this....
//NOTE: We DO want to dispose of this object because we are the ones allocating it
using (VistaDBConnection conn = new VistaDBConnection("Context Connection=true"))
{
conn.Open();
using (VistaDBCommand command = new VistaDBCommand())
{
command.Connection = conn;
command.CommandText = "SELECT @@Version";
versionString = Convert.ToString(command.ExecuteScalar());
return 0;
}
}
}
catch (Exception e)
{
throw new ApplicationException("Unable to get the database version due to Application Error", e);
}
}
/// <summary>
/// Call the Sql Function version to get the database version
/// </summary>
public static void CallGetDatabaseVersionFunctionSQL()
{
Console.WriteLine("Attempting to execute CLR Function GetDatabaseVersionFunction");
using (VistaDBConnection connection = new VistaDBConnection(SampleRunner.ConnectionString))
{
connection.Open();
try
{
// Straight forward way to call a function is just using SELECT
// You cannot EXEC a SqlFunction, and you cannot set the command here to be a stored proc
// Setting this command to a stored proc is a common error, the two are not the same
// SqlFunction = SELECT to call
// SqlProcdure = EXEC or direct call using StoredProcedure command type
using (VistaDBCommand command = new VistaDBCommand())
{
command.Connection = connection;
command.CommandText = "SELECT GetVersionFunction();";
// The results are returned as a part of the standard rowset, so we only need to get back the first entry
Console.WriteLine(Convert.ToString(command.ExecuteScalar()));
}
}
catch (Exception e)
{
Console.WriteLine("Failed to execute CLR Function GetVersionFunction, Reason: " + e.Message);
}
}
}
/// <summary>
/// Execute a VistaDBCommand (that returns a 1x1 resultset) against the specified VistaDBTransaction
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(trans, CommandType.Text, "Select count(Order) from TableTransaction where ProdId=?", new VistaDBParameter("@prodid", 24));
/// </remarks>
/// <param name="transaction">A valid VistaDBTransaction</param>
/// <param name="commandType">The CommandType (TableDirect, Text)</param>
/// <param name="commandText">The T-SQL command</param>
/// <param name="commandParameters">An array of VistaDBParamters used to execute the command</param>
/// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(VistaDBTransaction transaction, CommandType commandType, string commandText, params VistaDBParameter[] commandParameters)
{
if( transaction == null ) throw new ArgumentNullException( "transaction" );
if( transaction != null && transaction.Connection == null ) throw new ArgumentException( "The transaction was rollbacked or commited, please provide an open transaction.", "transaction" );
// Create a command and prepare it for execution
VistaDBCommand cmd = new VistaDBCommand();
bool mustCloseConnection = false;
PrepareCommand(cmd, (VistaDBConnection)transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
// Execute the command & return the results
object retval = cmd.ExecuteScalar();
// Detach the VistaDBParameters from the command object, so they can be used again
cmd.Parameters.Clear();
return retval;
}
/// <summary>
/// Execute a VistaDBCommand (that returns a 1x1 resultset) against the specified VistaDBConnection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// int orderCount = (int)ExecuteScalar(conn, CommandType.Text, "Select count(Order) from TableTransaction where ProdId=?", new VistaDBParameter("@prodid", 24));
/// </remarks>
/// <param name="connection">A valid VistaDBConnection</param>
/// <param name="commandType">The CommandType (TableDirect, Text)</param>
/// <param name="commandText">The T-SQL command</param>
/// <param name="commandParameters">An array of VistaDBParamters used to execute the command</param>
/// <returns>An object containing the value in the 1x1 resultset generated by the command</returns>
public static object ExecuteScalar(VistaDBConnection connection, CommandType commandType, string commandText, params VistaDBParameter[] commandParameters)
{
if( connection == null ) throw new ArgumentNullException( "connection" );
// Create a command and prepare it for execution
VistaDBCommand cmd = new VistaDBCommand();
bool mustCloseConnection = false;
PrepareCommand(cmd, connection, (VistaDBTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection );
// Execute the command & return the results
object retval = cmd.ExecuteScalar();
// Detach the VistaDBParameters from the command object, so they can be used again
cmd.Parameters.Clear();
if( mustCloseConnection )
connection.Close();
return retval;
}