OleDb: why can't I just fill my dataset with the full schema and information from my datasource easily?

Question

This seems really ridiculous.. what am I missing?

I have an access database with 5 tables.

I want to fill a dataset with the entire contents of the database.

Why can't it roughly look like this?:

dim dConnection as new oleDbConnection(connection info)

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

da.fill(ds)

Instead I'm having to create an adapter for EVERY table, tab the table name (why?), fill the schema, and then fill the table.

This would be worthless for a huge database... so there must be a simpler way to go about this?

Thanks!!!!!!

Answer 1

See this codeguru forum post - the last answer in the page provides a function for loading the whole access database into a dataset:

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