
Abstrakte Basisklasse für Datenprovider, die auf Daten einer IDbConnection zugreifen. Die konkreten Implementierungen in dieser Assembly sind die OleDbConnectionDataProvider Klasse, die OracleConnectionDataProvider Klasse und die SqlConnectionDataProvider Klasse. Sie können Ihre eigenen spezifischen Ableitungen hinzufügen, die IDbConnection verwenden, wenn Sie Zugriff auf die Datenbank-Schemainformationen für Ihren .NET Datenprovider haben (Tabellen und Relationen). Diese Klasse ist serialisierbar.
Um Ihre eigene Ableitung zu schreiben, überschreiben Sie die Init() Methode und übergeben alle Tabellen und Relationen an das protected Provider Member. Beachten Sie dazu das untenstehende Beispiel, um zu sehen wie dies in der SqlConnectionDataProvider Klasse gemacht wird. Solange Ihr Provider konform zu ISO SQL ist, sollten es nicht erforderlich sein weitere Änderungen vorzunehmen, die Basisklasse kümmert sich automatisch um das gesamte SQL Handling.
Überschreiben Sie die OnTranslateFilterSyntax Methode um das standardmäßige Verhalten für die Filtersyntax-Übersetzung zu ändern. Beachten Sie dazu das IAdvancedFiltering Interface für Details und beachten Sie ebenfalls das untenstehende Beispiel, um zu sehen wie diese Methode in der OracleConnectionDataProvider Klasse überschrieben wird. In diesem Fall wird nur die Behandlung der SUBSTRING SQL Funktion geändert, da der Name dieser Funktion in Oracle SUBSTR ist.
'Deklaration
Public MustInherit Class DbConnectionDataProvider Implements ICanHandleUsedIdentifiers, IDataProvider, combit.Reporting.ISupportsLogger
public abstract class DbConnectionDataProvider : ICanHandleUsedIdentifiers, IDataProvider, combit.Reporting.ISupportsLogger
public ref class DbConnectionDataProvider abstract : public ICanHandleUsedIdentifiers, IDataProvider, combit.Reporting.ISupportsLogger
protected override void Init() { if (Initialized) return; List<String> passedRelationNames = new List<string>(); Connection.Open(); try { DataTable dt = (Connection as SqlConnection).GetSchema("Tables"); foreach (DataRow dr in dt.Rows) { string tableSchema = dr["TABLE_SCHEMA"].ToString(); string tableType = dr["TABLE_TYPE"].ToString(); string parentTableName = dr["TABLE_NAME"].ToString(); switch (tableType) { case "BASE TABLE": if ((SupportedElementTypes & DbConnectionElementTypes.Table) == 0) continue; break; case "VIEW": if ((SupportedElementTypes & DbConnectionElementTypes.View) == 0) continue; break; default: continue; } // pass table SqlConnection newConnection = DbCommandSetDataProviderHelper.CloneConnection(Connection) as SqlConnection; SqlCommand cmd = new SqlCommand("Select * From \"" + (String.IsNullOrEmpty(tableSchema) ? parentTableName+"\"" : tableSchema + "\".\"" + parentTableName) + "\"", newConnection); Provider.AddCommand(cmd as IDbCommand, parentTableName); // pass relations string commandText = "sp_fkeys @pktable_name = '" + parentTableName + "'"; if (!String.IsNullOrEmpty(tableSchema)) { commandText+= ", @pktable_owner = '"+tableSchema+ "'"; } cmd = new SqlCommand(commandText, Connection as SqlConnection); SqlDataReader reader = cmd.ExecuteReader(); while (reader.Read()) { string childColumnName = reader.GetSqlString(7).ToString(); string parentColumnName = reader.GetSqlString(3).ToString(); // combined primary key, add key field to last relation on stack if (reader.GetInt16(8) > 1) { IDataProvider providerInterface = (Provider as IDataProvider); DbCommandTableRelation lastRelation = providerInterface.Relations[providerInterface.Relations.Count - 1] as DbCommandTableRelation; lastRelation.ChildColumnName += '\t' + childColumnName; lastRelation.ParentColumnName += '\t' + parentColumnName; continue; } string childTableName = reader.GetSqlString(6).ToString(); string relName = reader.GetSqlString(2).ToString() + "2" + childTableName; int relationIndex = 1; string formatString = relName+"{0}"; while (passedRelationNames.Contains(relName)) { relName = String.Format(formatString, relationIndex); relationIndex++; } passedRelationNames.Add(relName); Provider.AddRelation(relName, parentTableName, childTableName, parentColumnName, childColumnName); } reader.Close(); } } finally { Connection.Close(); Initialized = true; } }
Protected Overloads Overrides Sub Init() If Initialized Then Return End If Dim passedRelationNames As List(Of [String]) = New List(Of String)() Connection.Open() Try Dim dt As DataTable = (TryCast(Connection, SqlConnection)).GetSchema("Tables") For Each dr As DataRow In dt.Rows Dim tableSchema As String = dr("TABLE_SCHEMA").ToString() Dim tableType As String = dr("TABLE_TYPE").ToString() Dim parentTableName As String = dr("TABLE_NAME").ToString() Select Case tableType Case "BASE TABLE" If (SupportedElementTypes And DbConnectionElementTypes.Table) = 0 Then Continue Select End If Exit Select Case "VIEW" If (SupportedElementTypes And DbConnectionElementTypes.View) = 0 Then Continue Select End If Exit Select Case Else Continue Select End Select ' pass table Dim newConnection As SqlConnection = TryCast(DbCommandSetDataProviderHelper.CloneConnection(Connection), SqlConnection) Dim cmd As New SqlCommand("Select * From """ + (If([String].IsNullOrEmpty(tableSchema), parentTableName + """", tableSchema + """.""" + parentTableName)) + """", newConnection) Provider.AddCommand(TryCast(cmd, IDbCommand), parentTableName) ' pass relations Dim commandText As String = "sp_fkeys @pktable_name = '" + parentTableName + "'" If Not [String].IsNullOrEmpty(tableSchema) Then commandText += ", @pktable_owner = '" + tableSchema + "'" End If cmd = New SqlCommand(commandText, TryCast(Connection, SqlConnection)) Dim reader As SqlDataReader = cmd.ExecuteReader() While reader.Read() Dim childColumnName As String = reader.GetSqlString(7).ToString() Dim parentColumnName As String = reader.GetSqlString(3).ToString() ' combined primary key, add key field to last relation on stack If reader.GetInt16(8) > 1 Then Dim providerInterface As IDataProvider = (TryCast(Provider, IDataProvider)) Dim lastRelation As DbCommandTableRelation = TryCast(providerInterface.Relations(providerInterface.Relations.Count - 1), DbCommandTableRelation) lastRelation.ChildColumnName += ControlChars.Tab + childColumnName lastRelation.ParentColumnName += ControlChars.Tab + parentColumnName Continue While End If Dim childTableName As String = reader.GetSqlString(6).ToString() Dim relName As String = reader.GetSqlString(2).ToString() + "2" + childTableName Dim relationIndex As Integer = 1 Dim formatString As String = relName + "{0}" While passedRelationNames.Contains(relName) relName = [String].Format(formatString, relationIndex) System.Math.Max(System.Threading.Interlocked.Increment(relationIndex),relationIndex - 1) End While passedRelationNames.Add(relName) Provider.AddRelation(relName, parentTableName, childTableName, parentColumnName, childColumnName) End While reader.Close() Next Finally Connection.Close() Initialized = True End Try End Sub
protected override void OnTranslateFilterSyntax(object sender, TranslateFilterSyntaxEventArgs e) { switch (e.ArgumentType) { case LlExpressionArgumentType.Function: switch (e.Name.ToString().ToUpper()) { case "MID$": if (e.ArgumentCount == 2) e.Result = (String.Format("(SUBSTR({0},{1}))", e.Argument1.ToString(), e.Argument2.ToString() + "+1")); else e.Result = (String.Format("(SUBSTR({0},{1},{2}))", e.Argument1.ToString(), e.Argument2.ToString() + "+1", e.Argument3.ToString())); break; case "LEFT$": e.Result = (String.Format("(SUBSTR({0},0,{1}))", e.Argument1.ToString(), e.Argument2.ToString())); break; case "RIGHT$": e.Result = (String.Format("(SUBSTR({0},-{1},{1}))", e.Argument1.ToString(), e.Argument2.ToString())); break; default: e.Result = null; break; } break; default: e.Result = null; break; } }
System.Object
combit.Reporting.DataProviders.DbConnectionDataProvider
combit.Reporting.DataProviders.CDataDataProvider
combit.Reporting.DataProviders.DB2ConnectionDataProvider
combit.Reporting.DataProviders.OdbcConnectionDataProvider
combit.Reporting.DataProviders.OleDbConnectionDataProvider
combit.Reporting.DataProviders.OracleConnectionDataProvider
combit.Reporting.DataProviders.SqlConnectionDataProvider
combit.Reporting.DataProviders.SQLiteConnectionDataProvider
Plattformen: Windows 10 (Version 21H2 - 22H2), Windows 11 (21H2 - 23H2), Windows Server 2016 - 2022
.NET: .NET Framework 4.8, .NET 6, .NET 8, .NET 9