Step 3) Tables, Fields, and Records

Prerequisites
Understanding Tables, Fields, and Records
Learning Resources

Prerequisites

Introduction to Databases

Understanding Tables, Fields, and Records

In a database, data is organized and stored in data structures known as tables.
A table contains information about one thing. For example, a contacts table would store information about contacts, and only about contacts.

The data stored in a table is divided and structured into attributes that comprise the thing for which the table is storing data. For example, a contacts table would need to store at least the following attributes of a contact: First name, Last name, Address, Zip Code. In the resulting data structure, the term "field" is used in place of "attribute".

One way of visualizing the data stored in a table is to think of a spreadsheet, since a spreadsheet presents data in a tabular format comprised of columns and rows. In this case, the spreadsheet is the equivalent of a table, and the columns are the attributes or fields.

In a table, or a spreadsheet, each row contains the set of data for all attributes/fields for one instance of the thing for which the table is storing data. For example, in a contacts table, a row would be the set of data attributes for one contact: the contact’s First name, Last name, Address etc. The set of attributes for one instance of the thing for which the table is storing data, is known as a record.

So in a database we have records of data, comprised of fields, stored in tables. Records are written to disk for permanent storage.

Learning Resources

Video Tech Tips:

Getting Started: Tables
This video tech tip shows the mechanics of creating tables

Getting Started: Fields
This video tech tip shows the mechanics of creating fields

Primary Key
Every table must have a field that contains a unique identifying value for each record; the Primary Key. This video tech tip explains the concept of the Primary Key, and its implementation in a Table.

4th Dimension Documentation:

4th Dimension QuickStart Guide (versions for 4D 6.8 or 4D 2003)
Pages 14 - 19
A brief hands on tutorial for creating tables and fields.

4th Dimension Design Reference (PDF)
Pages 115 – 154
These pages provide step by step directions for creating tables and fields. Data types and field attributes (including indexing) are covered, as well as subtables (multi-valued fields). Background theory concerning tables, fields, and relations is provided.

Books:

Jumpstart 4D
Chapter 3, pages 3 – 1 thru 3 – 14
These pages provide step by step directions for creating tables and fields. Data types and field attributes (including indexing) are covered, as well as subtables (multi-valued fields).

4D v 6.8 Getting Started
Pages 13 - 54
These pages provide step by step directions for creating tables and fields. Data types and field attributes are covered, including subtables (multi-valued fields). Table and field design theory is also covered.

Designing Relational Databases (PDF)
A full hands-on course in database design theory.

Training:

Application Building with 4D
Fee based, week long training, The fastest comprehensive way to learn 4D.

Custom training
Contact 4D, Inc.
Tel: 408-557-4600