retrieve all database tables with ADO

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//How to retrieve all database tables with ADO

unit dbTables;

interface

uses ADODb;

type
  TTableType = (ttTable, ttView, ttSynonym, ttSystemTable, ttAccessTable);

type
  TTableTypes = set of TTableType;

type
  TTableItem = record
    ItemName: string;
    ItemType: string;
  end;

type
  TTableItems = array of TTableItem;

function addFilter(string1, string2: string): string;
function ADODbTables(ADOConnection: TADOConnection; types: TTableTypes): TTableItems;

implementation

function addFilter(string1, string2: string): string;
begin
  if string1 <> '' then
    Result := string1 + ' or ' + string2
  else
    Result := string2;
end;

function ADODbTables(ADOConnection: TADOConnection; types: TTableTypes): TTableItems;
var
  ADODataSet: TADODataSet;
  i: integer;
begin
  ADODataSet := TADODataSet.Create(nil);
  ADODataSet.Connection := ADOConnection;
  ADOConnection.OpenSchema(siTables, EmptyParam, EmptyParam, ADODataSet);

  if (ttTable in types) then
    ADODataSet.Filter := addFilter(ADODataSet.Filter, '(TABLE_TYPE = ''TABLE'')');

  if (ttView in types) then
    ADODataSet.Filter := addFilter(ADODataSet.Filter, '(TABLE_TYPE = ''VIEW'')');

  if (ttSynonym in types) then
    ADODataSet.Filter := addFilter(ADODataSet.Filter, '(TABLE_TYPE = ''SYNONYM'')');

  if (ttSystemTable in types) then
    ADODataSet.Filter := addFilter(ADODataSet.Filter, '(TABLE_TYPE = ''SYSTEM TABLE'')');

  if (ttAccessTable in types) then
    ADODataSet.Filter := addFilter(ADODataSet.Filter, '(TABLE_TYPE = ''ACCESS TABLE'')');

  ADODataSet.Filtered := True;

  SetLength(Result, ADODataSet.RecordCount);

  i := 0;
  with ADODataSet do
  begin
    First;
    while not EOF do
    begin
      with Result[i] do
      begin
        ItemName := FieldByName('TABLE_NAME').AsString;
        ItemType := FieldByName('TABLE_TYPE').AsString;
      end;
      Inc(i);
      Next;
    end;
  end;

  ADODataSet.Free;
end;

end.

{
Example: create a new project and add a TADOConnection (ADOConnection1),
a TButton (Button1) and a TMemo (Memo1); assign a ConnectionString to the
TADOConnection component and set "ADOConnection1.Active := True"
}

procedure TForm1.Button1Click(Sender: TObject);
var
  output: ttableitems;
  i: integer;
begin
  output := ADODbTables(ADOConnection1, [ttTable, ttView, ttSynonym]);
  //  output := ADODbTables(ADOConnection1, [ttSystemTable, ttAccessTable]);
  for i := Low(output) to High(output) do
  begin
    Memo1.Lines.Add(output[i].ItemName + '---' + output[i].ItemType);
  end;
  output := nil;
end;