Add a column to db-tables

The best way to do that is by using the
"Borland Database Desktop" under "Tools"
(I think) on the main Delphi2 menu.

John.

Ehh, well, I need to create a program that can add a column, so what I need is some code ;-)

Ok you seem to have missed that point in
your original question.

I don't believe you can simply add a column
to a table. I usually clone the structure
of the original table, add the column, and then
select the info I need. But you could try
simply adding the column to the existing table
if you want, although I think you will get
an error.

The code for adding a column to the table is:

   OriginalTable.FieldDefs.Add(FieldName,
      FieldType,FieldLen,false);

   e.g.
      Table1.FieldDefs.Add('SupCarry',ftString,SupLEN,false);
      Table1.FieldDefs.Add('PayCarAll',ftBoolean,0,false);
      Table1.FieldDefs.Add('Rate',ftFloat,0,false);
      Table1.Exclusive:= true;
   
      Table1.CreateTable;

I hope that helps,

John.

To jturpin

Here is a ex. of the code I use:

Table1.FieldDefs.Add('NewEntry:', ftString, 25, False);
Table1.CreateTable;

This will causs all the existing information in the table to be erased :-(, how is it possible to keep the existing information and still add an extra column?

Use SQL. For adding a new field, called 'TEST' to the ANIMALS table write:

with Query1 do
begin
  DatabaseName:='DBDEMOS';
  SQL.Text:='ALTER TABLE "ANIMALS.dbf" ADD TEST SMALLINT';
  ExecSQL;
end;

It must be possible to add a column, without using SQL.

You need to use the dbiDoRestructor procedure. There is an example at http://www.inprise.com/devsupport/bde/bdeapiex/dbidorestructure.html

Ok I have tried it all, and I simply don't get it, so I will take it one more time

I have to add a column to a paradox table, I need some code for Delphi 2.0 that does the trick.

The existing columns was made with fielddefs

with Table1.FieldDefs do
begin
  Clear;
  Add('Column1', ftString, 50, False);
  Add('Column2', ftString, 50, False);
end;
Table1.CreateTable;

if I try to add another column after table1.createtable was used,
I get an error.

Table1.FieldDefs.Add('Field3', ftString, 25, False);
Table1.FieldDefs.Update;
DBEdit3.DataField := 'Field3';  <-- error 'Field3 dosn't exist!'

If I call Table1.CreateTable again the whole table will be erased, all the information written in the table are lost.

Would someone give me an example that matches my table?

What's wrong with SQL?

The use of fielddefs will not create a row in the underlying table. It is an operator designed to manipulate TDataset, not the underlying table.

I really think that the best solution is to use SQL. Other than that, you can re-create a new table each time you want to add a column, migrate the data, then destroy the old table. As you can see, SQL is the cleaner option.

Ok, how do I use SQL?

I have already posted the answer on SQL and you rejected it.

To Ronit.

The reason that I really didn't want(ed) to use SQL, is that my application don't use SQL and I haven't used SQL before.

you gave me this SQL statement,

  SQL.Text:='ALTER TABLE "ANIMALS.dbf" ADD TEST SMALLINT';

I need a string field with the length 25, I haven't got any manual that covers SQL statements, so it is a bit tricky to figure out how the statement should look, will help me with that?

Thanx!!