Offline Modus Verbesserungen, SMB Share für User FIX

Dokumentation/Classes/cSQL2SQLLite.vb

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+Imports System.Data.SqlClient
+Imports System.Data.SQLite
+
+Public Class cSQL2SQLLite
+
+
+    Function Main(tableName As String)
+
+        Dim sqlServerConString = Class1.DBDoku
+        Dim sqliteFile As String = "C:\verag\offline_db.sqlite"
+        Dim sqliteConnString As String = $"Data Source={sqliteFile};Version=3;"
+
+
+
+        UpdateOrCreateTable(sqlServerConString, sqliteConnString, tableName)
+        CopyDataIncrementally(sqlServerConString, sqliteConnString, tableName)
+
+    End Function
+
+
+    Sub UpdateOrCreateTable(sqlServerConnectionString As String, localSqlServerConnectionString As String, tableName As String)
+        ' SQL Server-Abfrage für die Spalteninformationen
+        Dim query As String = $"SELECT COLUMN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH, IS_NULLABLE FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = '{tableName}'"
+        Dim columnDefinitions As New List(Of String)
+
+        ' Abfrage für die Spaltenstruktur der Remote-Tabelle
+        Using con As New SqlConnection(sqlServerConnectionString)
+            con.Open()
+            Using cmd As New SqlCommand(query, con)
+                Using reader As SqlDataReader = cmd.ExecuteReader()
+                    While reader.Read()
+                        Dim columnName As String = reader("COLUMN_NAME").ToString()
+                        Dim dataType As String = reader("DATA_TYPE").ToString()
+                        If reader("CHARACTER_MAXIMUM_LENGTH") IsNot DBNull.Value Then
+                            dataType &= $"({reader("CHARACTER_MAXIMUM_LENGTH").ToString()})"
+                        End If
+                        Dim isNullable As String = If(reader("IS_NULLABLE").ToString() = "YES", "NULL", "NOT NULL")
+                        columnDefinitions.Add($"{columnName} {dataType} {isNullable}")
+                    End While
+                End Using
+            End Using
+        End Using
+
+        ' Die lokale SQL Server-Datenbank, in der die Tabelle erstellt wird
+        Using localSqlCon As New SqlConnection(localSqlServerConnectionString)
+            localSqlCon.Open()
+
+            ' Prüfen, ob die Tabelle bereits existiert
+            Dim tableExistsQuery As String = $"SELECT 1 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = '{tableName}'"
+            Using cmd As New SqlCommand(tableExistsQuery, localSqlCon)
+                Dim exists As Object = cmd.ExecuteScalar()
+                If exists Is Nothing Then
+                    ' Erstelle die Tabelle, wenn sie nicht existiert
+                    Dim createTableSQL As String = $"CREATE TABLE {tableName} ({String.Join(", ", columnDefinitions)});"
+                    Using createCmd As New SqlCommand(createTableSQL, localSqlCon)
+                        createCmd.ExecuteNonQuery()
+                    End Using
+                Else
+                    ' Falls die Tabelle bereits existiert, überprüfe und füge neue Spalten hinzu
+                    For Each columnDef In columnDefinitions
+                        Dim columnName As String = columnDef.Split(" ")(0)
+                        Dim addColumnSQL As String = $"ALTER TABLE {tableName} ADD COLUMN {columnDef};"
+                        Try
+                            Using alterCmd As New SqlCommand(addColumnSQL, localSqlCon)
+                                alterCmd.ExecuteNonQuery()
+                            End Using
+                        Catch ex As Exception
+                            ' Falls die Spalte bereits existiert, wird die Exception ignoriert
+                        End Try
+                    Next
+                End If
+            End Using
+        End Using
+    End Sub
+
+
+    Sub CopyDataIncrementally(sqlServerConnectionString As String, sqliteConnectionString As String, tableName As String)
+        Dim query As String = $"SELECT * FROM {tableName}"
+
+        Using sqlCon As New SqlConnection(sqlServerConnectionString)
+            sqlCon.Open()
+            Using cmd As New SqlCommand(query, sqlCon)
+                Using reader As SqlDataReader = cmd.ExecuteReader()
+                    Using sqliteCon As New SQLiteConnection(sqliteConnectionString)
+                        sqliteCon.Open()
+
+                        While reader.Read()
+                            Dim columns As New List(Of String)
+                            Dim values As New List(Of String)
+                            Dim parameters As New List(Of SQLiteParameter)
+
+                            For i As Integer = 0 To reader.FieldCount - 1
+                                Dim columnName As String = reader.GetName(i)
+                                columns.Add(columnName)
+                                values.Add($"@{columnName}")
+                                parameters.Add(New SQLiteParameter($"@{columnName}", reader.GetValue(i)))
+                            Next
+
+                            Dim insertSQL As String = $"INSERT OR IGNORE INTO {tableName} ({String.Join(", ", columns)}) VALUES ({String.Join(", ", values)})"
+                            Using insertCmd As New SQLiteCommand(insertSQL, sqliteCon)
+                                insertCmd.Parameters.AddRange(parameters.ToArray())
+                                insertCmd.ExecuteNonQuery()
+                            End Using
+                        End While
+                    End Using
+                End Using
+            End Using
+        End Using
+    End Sub
+
+    Function MapSQLServerToSQLiteType(sqlType As String, length As Object) As String
+        Select Case sqlType.ToLower()
+            Case "int", "bigint", "smallint", "tinyint"
+                Return "INTEGER"
+            Case "bit"
+                Return "BOOLEAN"
+            Case "decimal", "numeric", "money", "smallmoney", "float", "real"
+                Return "REAL"
+            Case "char", "nchar", "varchar", "nvarchar", "text", "ntext"
+                Return "TEXT"
+            Case "datetime", "smalldatetime", "date", "time", "datetime2"
+                Return "TEXT"
+            Case Else
+                Return "TEXT"
+        End Select
+    End Function
+
+End Class