ezaccess2000.pas

很管用的GIS控件

        'This column is the identifier for the entities';
      // Specify whether this column allows NULLs.  The Nullable property
      // = Access's Required property but the specification is inverted:
      //
      //   If Nullable = false then Required = true
      Properties['Nullable'].Value := false;
    end;
  Table.Columns.Append(Column1, Unassigned, Unassigned);

  Column2 := CoColumn.Create;
  with Column1 do
    begin
      ParentCatalog := Catalog;
      Name := 'DELETED';
      Type_ := adBoolean;
      // A bug in ADO 2.5 means that the Default property value will not be
      // accepted and no error will be given. This bug is not in 2.1 or 2.6.
      Properties['Default'].Value := False;

      // Specify a human-readable string description of the column.
      //
      // Note that you must use the expanded syntax in order to write to
      // the Properties collection.  If you try to use an abbreviated syntax
      // based on the Properties collection default (Value), such as:
      //
      //   Properties['x'] := false
      //
      // you will get a compiler error about trying to write to a read-only
      // property.
      Properties['Description'].Value :=
        'This column indicates if the entity is considered deleted';
      // Specify whether this column allows NULLs.  The Nullable property
      // = Access's Required property but the specification is inverted:
      //
      //   If Nullable = false then Required = true
      Properties['Nullable'].Value := false;
    end;
  Table.Columns.Append(Column2, Unassigned, Unassigned);

  For I := 0 To AFieldList.count - 1 Do
  Begin
    s:= AFieldList[I];
    LoadField;
    If Not v Then
      EzGisError( SErrWrongField );

    Column:= CoColumn.Create;

    Case ft[1] Of
      'C':
        begin
          with Column do
            begin
              ParentCatalog := Catalog;
              Name := fs;
              // The adVarWchar and adWchar types produce Unicode (WideString) strings
              // in Access 2000.  If you are creating an Access 97 database you will
              // get adVarChar and adChar (ANSI) strings instead.
              Type_ := adVarChar;
              // DefinedSize only has meaning for strings (but not memos).
              DefinedSize := fl; // characters
              // Specify a human-readable string description of the column.
              //
              // Note that you must use the expanded syntax in order to write to
              // the Properties collection.  If you try to use an abbreviated syntax
              // based on the Properties collection default (Value), such as:
              //
              //   Properties['x'] := false
              //
              // you will get a compiler error about trying to write to a read-only
              // property.
              //Properties['Description'].Value :=
              //  'This column is part 1 of a multi-column primary key';
              // Specify whether this column allows NULLs.  The Nullable property
              // = Access's Required property but the specification is inverted:
              //
              //   If Nullable = false then Required = true
              Properties['Nullable'].Value := false;
              // Determines whether zero-length strings can be inserted into this
              // column. Ignored for data types that are not strings. This is similar
              // to the Nullable property but distinct. Zero-length strings are not
              // NULLs in Jet.
              Properties['Jet OLEDB:Allow Zero Length'].Value := false;
              // Determines whether Jet should compress UNICODE strings on the disk.
              // This applies only to the version 4.0 .mdb file format and is ignored
              // when running against all other storage formats.  The default is true.
              //Properties['Jet OLEDB:Compressed UNICODE Strings'].Value := true;
            end;
        end;
      'F', 'N':
        If fd = 0 Then
        begin
          with Column do
          begin
            ParentCatalog := Catalog;
            Name := fs;
            Type_ := adInteger;
            //Properties['Default'].Value := 0;

            //Properties['Jet OLEDB:Column Validation Text'].Value :=
            //  'Please enter a number greater than or equal to 1';  adBoolean

            //Properties['Description'].Value :=
            //  'This column is the identifier for the entities';
            //Properties['Nullable'].Value := false;
          end;
        end Else
        begin
          with Column do
          begin
            ParentCatalog := Catalog;
            Name := fs;
            Type_ := adDouble;
            //Properties['Default'].Value := 0;

            //Properties['Jet OLEDB:Column Validation Text'].Value :=
            //  'Please enter a number greater than or equal to 1';  adBoolean

            //Properties['Description'].Value :=
            //  'This column is the identifier for the entities';
            //Properties['Nullable'].Value := false;
          end;
        end;
      'M':
        begin
          with Column do
            begin
              ParentCatalog := Catalog;
              Name := fs;
              Type_ := adLongVarChar;
              //Properties['Default'].Value := 0;

              //Properties['Jet OLEDB:Column Validation Text'].Value :=
              //  'Please enter a number greater than or equal to 1';  adBoolean

              //Properties['Description'].Value :=
              //  'This column is the identifier for the entities';
              //Properties['Nullable'].Value := false;
            end;
        end;
      'G', 'B':
        begin
          with Column do
            begin
              ParentCatalog := Catalog;
              Name := fs;
              Type_ := adVarBinary;
              //Properties['Default'].Value := 0;

              //Properties['Jet OLEDB:Column Validation Text'].Value :=
              //  'Please enter a number greater than or equal to 1';  adBoolean

              //Properties['Description'].Value :=
              //  'This column is the identifier for the entities';
              //Properties['Nullable'].Value := false;
            end;
        end;
      'L':
        begin
          with Column do
            begin
              ParentCatalog := Catalog;
              Name := fs;
              Type_ := adBoolean;
              //Properties['Default'].Value := 0;

              //Properties['Jet OLEDB:Column Validation Text'].Value :=
              //  'Please enter a number greater than or equal to 1';  adBoolean

              //Properties['Description'].Value :=
              //  'This column is the identifier for the entities';
              //Properties['Nullable'].Value := false;
            end;
        end;
      'D':
        begin
          with Column do
            begin
              ParentCatalog := Catalog;
              Name := fs;
              Type_ := adDBDate;
              //Properties['Default'].Value := 0;

              //Properties['Jet OLEDB:Column Validation Text'].Value :=
              //  'Please enter a number greater than or equal to 1';  adBoolean

              //Properties['Description'].Value :=
              //  'This column is the identifier for the entities';
              //Properties['Nullable'].Value := false;
            end;
        end;
      'T':
        begin
          with Column do
            begin
              ParentCatalog := Catalog;
              Name := fs;
              Type_ := adDBTime;
              //Properties['Default'].Value := 0;

              //Properties['Jet OLEDB:Column Validation Text'].Value :=
              //  'Please enter a number greater than or equal to 1';  adBoolean

              //Properties['Description'].Value :=
              //  'This column is the identifier for the entities';
              //Properties['Nullable'].Value := false;
            end;
        end;
      'I':
        begin
          with Column do
            begin
              ParentCatalog := Catalog;
              Name := fs;
              Type_ := adInteger;
              //Properties['Default'].Value := 0;

              //Properties['Jet OLEDB:Column Validation Text'].Value :=
              //  'Please enter a number greater than or equal to 1';  adBoolean

              //Properties['Description'].Value :=
              //  'This column is the identifier for the entities';
              //Properties['Nullable'].Value := false;
            end;
        end;
    End;
    Table.Columns.Append(Column, Unassigned, Unassigned);
  End;

  { append table to catalog }
  Catalog.Tables.Append( Table );

  // Refresh the database schema
  Catalog.Tables.Refresh;

  { create indexes }
  Index1 := CoIndex.Create;
  with Index1 do
  begin
    Name := Column1.Name;
    Columns.Append(Column1.Name, Column1.Type_, Column1.DefinedSize);
    PrimaryKey := false;
    Unique := true;
  end;

  { create primary key }
  Index2 := CoIndex.Create;
  with Index2 do
  begin
    Name := 'PrimaryKey';
    Columns.Append(Column1.Name, Column1.Type_, Column1.DefinedSize);
    // The SortOrder property only has meaning for index columns.
    // adSortAscending is the default.
    Columns[Column1.Name].SortOrder := adSortAscending;
    PrimaryKey := True;
    // The Unique property here seems to be ignored when the PrimaryKey
    // property is true, hence the use of the MIndex1 & MIndex2 objects
    // above.
    Unique := True;
    // Columns which are null will not have an index entry.
    // adIndexNullsDisallow is the default.
    IndexNulls := adIndexNullsDisallow;
    // Specify whether the index is clustered.  The default is false.
    // Access does not support clustering, but SQL Server does.
    Clustered := false;
  end;

  { append indexes to tables }
  Table.Indexes.Append(Index1, EmptyParam);

  { append primary keys to tables }
  Table.Indexes.Append(Index2, EmptyParam);

  Catalog.Set_ActiveConnection(Unassigned);

  Catalog := nil;

End;

Constructor TEzADOXTable.Create( Gis: TEzBaseGis; Const FName: String;
  ReadWrite, Shared: boolean );
var
  AccessMdb: string;
Begin
  inherited Create( Gis, FName, ReadWrite, Shared );
  if Length(FName) > 0 then
  begin
    AccessMdb:= ChangeFileExt( Gis.FileName, '.mdb' );
    If not ADOConnection.Connected then
    begin
      { the connection string must be already defined in main unit }
      ADOConnection.Connected:= true;
    end;
    FADOTable:= TADOTable.Create( Nil );
    With FADOTable Do
    Begin
      Connection := ADOConnection;
      TableName:= ChangeFileExt( ExtractFileName( FName ), '' );
      ReadOnly:= Not ReadWrite;
      //Exclusive:= Not Shared;
      Open;
    End;
  end;
End;

Destructor TEzADOXTable.Destroy;
Begin
  If FADOTable <> Nil then
    FADOTable.Free;
  Inherited Destroy;
End;

Function TEzADOXTable.GetActive: boolean;
Begin
  result := FADOTable.Active;
End;

Procedure TEzADOXTable.SetActive( Value: boolean );
Begin
  FADOTable.Active := value;
End;

Function TEzADOXTable.GetRecNo: Integer;
Begin
  result := FADOTable.FieldByName( 'UID' ).AsInteger;
End;

Procedure TEzADOXTable.SetRecNo( Value: Integer );
Begin
  if FADOTable.IndexName <> '' then
  begin
    FADOTable.IndexName := ''; // primary index
    If Not FADOTable.Locate( 'UID',Value, [] ) Then
      EzGisError( 'Record not found !' );
  end else
  begin
    if FADOTable.FieldByName( 'UID' ).AsInteger <> Value then
    begin
      If Not FADOTable.Locate( 'UID',Value, [] ) Then
        EzGisError( 'Record not found !' );
    end;
  end;
End;

Procedure TEzADOXTable.Append( NewRecno: Integer );
Begin
  FADOTable.Insert;
  FADOTable.FieldByName( 'UID' ).AsInteger := NewRecno;
  FADOTable.Post;
End;

Function TEzADOXTable.BOF: Boolean;
Begin
  result := FADOTable.BOF;
End;

Function TEzADOXTable.EOF: Boolean;
Begin
  result := FADOTable.EOF;
End;

Function TEzADOXTable.DateGet( Const FieldName: String ): TDateTime;
Begin
  result := FADOTable.FieldByName( FieldName ).AsDateTime;
End;

Function TEzADOXTable.DateGetN( FieldNo: integer ): TDateTime;
Begin
  result := FADOTable.Fields[FieldNo - 1].AsdateTime;
End;

Function TEzADOXTable.Deleted: Boolean;
Begin
  result := FADOTable.FieldByName( 'DELETED' ).AsBoolean;
End;

Function TEzADOXTable.Field( FieldNo: integer ): String;
Begin
  result := FADOTable.Fields[FieldNo - 1].FieldName;
End;

Function TEzADOXTable.FieldCount: integer;
Begin
  result := FADOTable.Fields.Count;
End;

Function TEzADOXTable.FieldDec( FieldNo: integer ): integer;
Var
  Datatype: TFieldType;
Begin
  Datatype := FADOTable.Fields[FieldNo - 1].Datatype;
  If Datatype In ftNonTexttypes Then
    Result := 0
  Else
    Case Datatype Of
      ftstring{$IFDEF LEVEL4}, ftFixedChar,