OleDb：為什么我不能輕松地使用數據源中的完整架構和信息來填充數據集？

Question

這似乎很荒謬。我想念什么？

我有5個表的訪問數據庫。

我想用數據庫的全部內容填充數據集。

為什么它不能大致如此？ ：

dim dConnection as new oleDbConnection(connection info)

dim dAdapter as new oledbdataadapter(SelectCommand, dConnection)
dim dSet as oleDbDataset

da.fill(ds)

相反，我必須為每個表創建一個適配器，選擇表名（為什么？），填充架構，然后填充表。

對於一個龐大的數據庫，這將毫無價值……因此，必須有一種更簡單的方法來解決這個問題？

謝謝！！！！！！

Answer 1

請參閱此 codeguru論壇帖子-頁面中的最后一個答案提供了將整個訪問數據庫加載到數據集中的功能：

Protected Function getDataSetAndFill(ByRef connection As OleDb.OleDbConnection, Optional ByVal isExportSchema As Boolean = True) As DataSet

    Dim myDataSet As New DataSet
    Dim myCommand As New OleDb.OleDbCommand
    Dim myAdapter As New OleDb.OleDbDataAdapter

    myCommand.Connection = connection

    'Get Database Tables
    Dim tables As DataTable = connection.GetOleDbSchemaTable( _
        System.Data.OleDb.OleDbSchemaGuid.Tables, _
        New Object() {Nothing, Nothing, Nothing, "TABLE"})

    'iterate through all tables
    Dim table As DataRow
    For Each table In tables.Rows

        'get current table's name
        Dim tableName As String = table("TABLE_NAME")

        Dim strSQL = "SELECT * FROM " & "[" & tableName & "]"

        Dim adapter1 As New OleDb.OleDbDataAdapter(New OleDb.OleDbCommand(strSQL, connection))
        adapter1.FillSchema(myDataSet, SchemaType.Source, tableName)

        'Fill the table in the dataset
        myCommand.CommandText = strSQL
        myAdapter.SelectCommand = myCommand
        myAdapter.Fill(myDataSet, tableName)
    Next

    ''''''''''''''''''''''''''''''''''''''
    '''' Add relationships to dataset ''''
    ''''''''''''''''''''''''''''''''''''''

    'First, get relationships names from database (as well as parent table and child table names)
    Dim namesQuery As String = "SELECT DISTINCT szRelationship, szReferencedObject, szObject " & _
                                "FROM MSysRelationships"
    Dim namesCommand As New System.Data.OleDb.OleDbCommand(namesQuery, connection)
    Dim namesAdapter As New System.Data.OleDb.OleDbDataAdapter(namesCommand)
    Dim namesDataTable As New DataTable
    namesAdapter.Fill(namesDataTable)

    'Now, get MSysRelationship from database
    Dim relationsQuery As String = "SELECT * FROM MSysRelationships"
    Dim command As New System.Data.OleDb.OleDbCommand(relationsQuery, connection)
    Dim adapter As New System.Data.OleDb.OleDbDataAdapter(command)
    Dim relationsDataTable As New DataTable
    adapter.Fill(relationsDataTable)

    Dim relationsView As DataView = relationsDataTable.DefaultView
    Dim relationName As String
    Dim parentTableName As String
    Dim childTablename As String
    Dim row As DataRow

    For Each relation As DataRow In namesDataTable.Rows
        relationName = relation("szRelationship")
        parentTableName = relation("szReferencedObject")
        childTablename = relation("szObject")

        'Keep only the record of the current relationship
        relationsView.RowFilter = "szRelationship = '" & relationName & "'"

        'Declare two arrays for parent and child columns arguments
        Dim parentColumns(relationsView.Count - 1) As DataColumn
        Dim childColumns(relationsView.Count - 1) As DataColumn

        For i As Integer = 0 To relationsView.Count - 1
            parentColumns(i) = myDataSet.Tables(parentTableName). _
                            Columns(relationsView.Item(i)("szReferencedColumn"))
            childColumns(i) = myDataSet.Tables(childTablename). _
                            Columns(relationsView.Item(i)("szColumn"))
        Next

        Dim newRelation As New DataRelation(relationName, parentColumns, childColumns, False)
        myDataSet.Relations.Add(newRelation)
    Next

    If isExportSchema Then
        Dim schemaName = GetXmlSchemaFileName()
        If File.Exists(schemaName) Then File.SetAttributes(schemaName, FileAttributes.Normal)
        myDataSet.WriteXmlSchema(schemaName)
    End If
    Return myDataSet
End Function