Creating Tables at run-time


Tables always created at design time using Database Desktop which exists in Tools
menu. Database Desktop provides easy and visual way to design common database tables
such as Paradox , DBase, and Foxpro tables. When you want to deploy your applications
you need a clear copy of tables (empty tables ) these tables hold only fields structre,
indexes, validity checks and other table properties. After installing your database
application in target computer; empty tables will be copied and every thing will
goes well. Some times you need to create tables at run-time, without using Database
Desktop application, how you can do that?

Creating tables at run-time is a very simple task. Suppose that you want to create
a Telephone table (Phone.db) at run time which contains: ID, Name, Number, Address,
and Notes fields. ID is the primary key and there is a secondary index of Name field
called NameIndex. simply you can write procedure like below:

procedure CreatePhoneTable;
var
 NewTable: TTable;
begin
NewTable := TTable.Create(nil); // Create table object
  with  NewTable  do
begin
  TableName := 'C:\Data\Phone.db';
  TableType := ttDefault; // Paradox
    FieldDefs.Clear;

    (*** Create fields  ***)
    FieldDefs.Add('ID', ftAutoInc, 0, False);
  FieldDefs.Add('Name', ftString, 30, True);
  FieldDefs.Add('Number', ftString, 15, True);
  FieldDefs.Add('Address', ftString, 40, False);
  FieldDefs.Add('Notes', ftMemo, 200, False);

    (*** Create primary key ***)
    IndexDefs.Clear;
  IndexDefs.Add('', 'ID', [ixPrimary, ixUnique]);

  (*** Create Secondary index ***)
    IndexDefs.Add('NameIndex', 'Name', [ixCaseInsensitive]);

    (*** Create physical table ***)
    CreateTable;
 
       (*** Free NewTable object ***)
    Free;


end ; // With NewTable


end ;

Notes:

- Inorder to run this procedure you must include Db and  DBTables units in unit
clause.

- If table already exists it will be overwritten.

- You do not need to drop any data access components at design time to create tables
at run time.

See also:

Creating components at run-time