c-treeDB API for VB.Net

Relationships

drivers\vb.nav\tutorials\Tutorial2.vb

Now we will build some table/file relationships using the c-treeDB .NET Visual Basic Framework.

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

Note our simple Main() function:

Imports System

Imports FairCom.CtreeDb

Module Tutorial2HL

Dim MySession As CTSession

Dim tableCustOrdr As CTTable

Dim tableOrdrItem As CTTable

Dim tableItemMast As CTTable

Dim tableCustMast As CTTable

Dim recordCustOrdr As CTRecord

Dim recordOrdrItem As CTRecord

Dim recordItemMast As CTRecord

Dim recordCustMast As CTRecord

'

' main()

'

' The main() function implements the concept of "init, define, manage

' and you're done..."

'

Sub Main()

Initialize()

Define()

Manage()

Done()

Console.WriteLine(ControlChars.NewLine + "Press <ENTER> key to exit . . .")

Console.ReadLine()

End Sub

In This Section Init Define Manage Done