About the VFMC Web Site Database

Introduction

This document provides essential background information about the VFMC database which drives the dynamic pages of the web site, and explains the structure of tables of information stored in the database. As the functions of the web site have evolved, new, different tables have been added to support new functions, often in combination of other, existing tables. As you peruse this documentation you will find that some tables of information are re-used in a different context. This is a vital and valuable aspect of database use - as long as the information in any table in the database is correct and unambiguous, it can be re-used for any other function, in any other context to which it applies.

There is a most important consideration in the design of a database, one that minimises the work required to keep information correct and up to date, maximises the opportunities to re-use the information in new ways, and is efficient in use of computer resources. A good design does not repeat the same information in multiple places.

If we were to write down a list of all the VFMC events and the performers at those events, we would notice that quite a few performers appear in multiple places in the list. If we were to write down a list of all the performers who have performed at VFMC events, we would see several events for some performers, and some of those events would show the same event.

Throughout our database, we resolve these issues of duplication by dividing up lists (like those outlined above) into simpler lists which we call tables. We can produce a table of events without performer details (which might be duplicated) and a table of performers without detail of their events (which might also be duplicated). We then add another table which links the events and performers but without the need to store any details of either the event or the performer.

Definitions

Here are some definitions of terms that are used in these notes about databases:

TABLE

A Table is a list of information about things like events or performers. It can hold many different details about entry in the list.

FIELD

Each different sort of information held in a Table is called a Field. For example, a Performer tabble would have several Fields including their name, their web site address, some "blurb" text describing the act, etc.

ROW

Each individual thing which is described by a set of Fields in a Table is referred to as a Row. If you wrote out a list of performers and their phone numbers on paper, with each performer on a new line, each line (row) on the page would correspond to a particular performer. If that information is transcribed into a Datebase Table, then the information for each performer would be desribed as a Row in the Table.

DATABASE

A Database is the name given to all the information in a collection of related Tables, and the descriptions defining each Table and each of the Fields within each Table.

KEY

Each Table must have one or more Fields defined as the Key for that Table. Each Row in the Table must have a unique value in its Key Field(s). It is often useful to allocate number to uniquely define each Row in a Table, in which case a Field is required to store that number. For a Performer Table, this might be an allocated PerformerNo Field, and that Field would be defined as the Key for that Table.

VFMC Events

VFMC conducts a variety of events. Concerts, Music Sessins, Dances, Meetings etc. Each event has certain characteristics; it has a name, location, start and finish date and time etc. A database Table called "event" is used to hold event information. A full description of the Fields in the event table is shown here.

The Database hold a historical record of events since 13th April 1999. At some future date, it might become necessary to start to cull some very old events, but there is no prospect for that in the immediate future.

Most, but not all, VFMC events involve a performance with one or more performers.

VFMC Performers

VFMC enlists the services of performers for most of its events. We hold a collection of information about each performer. A database table called "performer" is used to hold performer information. A full description of the Fields in the performer table is shown here.

The official site of the Victorian Folk Music Club Incorporated (Reg No A2511Y) ABN 28 668 156 704

Last modified: August 14 2023 18:46.