Relationships

..\sdk\sql.dbx\Tutorial2\Unit1.pas

Now we will build some table/file relationships using the c-treeACE SQL CodeGear DBX Component - Delphi.

This tutorial will advance the concepts introduced in the first tutorial by expanding the number of tables. We will define key columns/fields and create specific indices for each table to form a relational model database.

Like all other examples in the c-tree tutorial series, this tutorial simplifies the creation and use of a database into four simple steps: Initialize(), Define(), Manage(), and You’re Done() !

Tutorial #2: Relational Model and Indexing

Here we add a bit more complexity, introducing multiple tables, with related indices in order to form a simple "relational" database simulating an Order Entry system. Here is an overview of what will be created:

• Initialize() - Connects to the c-treeACE Database Engine.
• Define() - Defines and creates the "custmast", "custordr", "ordritem" and the "itemmast" tables/files with related indices.
• Manage() - Adds some related rows/records to all tables/files. Then queries the database.
• Done() - Disconnects from c-treeACE Database Engine.

Note our simple mainline:

procedure TForm1.FormShow(Sender: TObject);

begin

    Initialize;

    Define;

    Manage;

end;

procedure TForm1.btnCloseClick(Sender: TObject);

begin

    Done;

    Close;

end;

We suggest opening the source code with your own editor.

Continue now to review these four steps.