Restructuring Tables

Delphi Database, Delphi Components from ComponentAce

Restructuring Tables

Previous Top Next

Use Absolute Database DBManager utility (...\AbsoluteDatabase\Ultils\Bin\DBManager.exe), if you would like to change table structure manually.

To alter table from your application using TABSTable component, you could perform the following steps:

1.	Open existing table to fill in RestructureFieldDefs and RestructureIndexDefs properties.

2.	Close table.

3.	Modify RestructureFieldDefs and RestructureIndexDefs properties (add, delete or change fields and indexes descriptions)

4.	Call RestructureTable method

Example:

var
  Log: String;

  {set up table component}
  ABSTable1.DatabaseName := 'emp_db';
  ABSTable1.TableName := 'employee';

  {fill in restructure properties}
  ABSTable1.Open;
  ABSTable1.Close;

  with ABSTable1 do
   begin
     {specifying new table fields}
     with RestructureFieldDefs do
   begin
         Add('Hobby',aftString,30,False);
         Add('Comment',aftMemo,0,False);
    end;
     {specifying new table indexes}
     with RestructureIndexDefs do
       begin
         Add('idxHobby','Hobby',[]);
       end;
     {restructure}
     if (RestructureTable(Log)) then
       ShowMessage('Restructure completed')
     else
       ShowMessage('Restructure errors: '+Log);
   end;

Note:   See also how to alter table using SQL ALTER TABLE Command.

Dec 21, 2024