How to Create a Table at Runtime

I was a VB programmer, until my recent shift to Delphi 2.0. How can I create a database in code?

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It depends on the type of database you want to build. However, I can show you how to do it with a Paradox table. Conceivably, it stands to reason that since the TTable is database-independent and if you've got the right settings in the BDE, you should be able to create a table with the TTable component in any database. This is not necessarily true. SQL tables are normally created using the SQL call CREATE TABLE. And each server has its own conventions for creating tables and defining fields. So it's important to note this if you're working with a SQL database. The problem is that SQL databases support different data types that aren't necessarily available in the standard BDE set. For instance, MS SQL server's NUMERIC data format is not necessarily a FLOAT as it's defined in the BDE. So your best bet would probably be to create SQL tables using SQL calls.
What you have to do is declare a TTable variable, create an instance, then with the TTable's FieldDefs property, add field definitions. Finally, you'll make a call to CreateTable, and your table will be created. Here's some example code:

{ "Add" is the operative function here.
  Add(const Name: string; DataType: TFieldType; Size: Word; Required: Boolean);
}
procedure CreateATable(DBName,            //Alias or path
                       TblName : String); //Table Name to Create
var
  tbl : TTable;
begin
  tbl := TTable.Create(Application);
  with tbl do begin
    Active := False;
    DatabaseName := DBName;
    TableName := TblName;
    TableType := ttParadox;
    with FieldDefs do begin
      Clear;
      Add('LastName', ftString, 30, False);
      Add('FirstName', ftString, 30, False);
      Add('Address1', ftString, 40, False);
      Add('Address2', ftString, 40, False);
      Add('City', ftString, 30, False);
      Add('ST', ftString, 2, False);
      Add('Zip', ftString, 10, False);
    end;

    {Add a Primary Key to the table}
    with IndexDefs do begin
      Clear;
      Add('Field1Index', 'LastName;FirstName', [ixPrimary, ixUnique]);
    end;
    
    CreateTable; {Make the table}
  end;
end;

The procedure above makes a simple contact table, first by defining the fields to be included in the table, then creating a primary key. As you can see, it's a pretty straightforward procedure. One thing you can do is to change the TableType property setting to a variable that's passed as a parameter to the procedure so you can create DBase or even ASCII tables. Here's snippet of how you'd accomplish that:

procedure CreateATable(DBName,                //Alias or path
                       TblName : String);     //Table Name to Create
                       TblType : TTableType); //ttDefault, ttParadox, ttDBase, ttASCII
var
  tbl : TTable;
begin
  tbl := TTable.Create(Application);
  with tbl do begin
    Active := False;
    DatabaseName := DBName;
    TableName := TblName;
    TableType := TblType;
    with FieldDefs do begin
      Clear;
      Add('LastName', ftString, 30, False);
      Add('FirstName', ftString, 30, False);
      Add('Address1', ftString, 40, False);
      Add('Address2', ftString, 40, False);
      Add('City', ftString, 30, False);
      Add('ST', ftString, 2, False);
      Add('Zip', ftString, 10, False);
    end;

    {Add a Primary Key to the table}
    with IndexDefs do begin
      Clear;
      Add('Field1Index', 'LastName;FirstName', [ixPrimary, ixUnique]);
    end;
    
    CreateTable; {Make the table}
  end;
end;

Pretty simple, right? One thing you should note is that the TableType property is only used for desktop databases. It doesn't apply to SQL tables.
Oh well, that's it in a nutshell. Have fun!