About Databases

Understanding databases

What is a database? - A collection of data that is relevant to a particular topic or purpose.

In everyday life, we meet databases in a variety of forms. A telephone book, a product catalogue, documents and folders in a filing cabinet - all of these can be considered to be databases.

As the quantity of information stored gets larger, it may be more convenient and efficient to store it electronically e.g. by using a software application such as Qudos 3.

The following is a brief explanation of some of the terms used with regard to databases:

Tables, fields and records
A software database stores information in tables. These are divided into fields and records.

Fields are categories or types of information e.g. people's names, telephone numbers etc. For example, in a library database there may be fields for book title, author, publisher, date published and so on. A field has two parts - the field name, and a space for the user to enter data.

A record is the information contained in various fields for one instance e.g. one book, one person, one meeting etc. To make viewing and editing easier, the information is often presented to you as a form.

Forms
In some cases, a form will display information for just one record - an example in Qudos 3 is the Meeting Minutes.

Where there is a need to display a number of records may together - a form is formatted as a list. An example in Qudos 3 is the Master Document List. These list forms generally display just a selection of the data for each record.

Data is not generally entered directly into a list - but by clicking on a button to open a separate Data entry form. Similarly, to view the full data contained in each record, the user would also open such a form. From various lists, the user may click on the New button to open a blank form, or select a record and click on the Edit button to view or change that particular record.

There are various methods to enter data into a form. For example:

• You may place the cursor in a field and type in your data
• You may use a 'combo box' to select from a pre-defined list of options. This method can save time and reduce the possibility of error. Qudos 3 uses combo boxes and various other selection methods such as calendar controls for date entry and spin buttons for entering numbers
• Sometimes data is automatically entered for you

By completing and saving a form, you create a new record.

Queries
Of course, when there is a quantity of information stored within the database, it becomes desirable to access it. Preferably, gaining that access should be easy and convenient. Most databases allow the user to perform queries. The designer may pre-set parameters for a query or allow you to set your own parameters. In each of its modules, Qudos 3 has Filters or Query builders for you to define your own query. These enable you to generate filtered lists of items that have something in common e.g. all safety audits that are still outstanding.

Reports
Another common feature of a database is printed reports. These may be based on forms, lists or queries.

Types of database

Computer databases generally one of two generic types - 'flat file' databases and 'relational' databases.

The simplest is the 'flat file' database - where all the information that you wish to hold is in one large table. One problem is that you can end up storing a lot of duplicate data. For example, if your database was for a book library, you might want to record their authors, and publishers. If one publisher had published 100 books, you would store their details 100 times. Your table would quickly grow in size, taking up large amounts of disk space. Then, if the publisher changed their name, you would have to change it 100 times in your database - very time consuming, and easy to make mistakes!

A more advanced type of database - the relational database - solves the problem. This stores information in a number of smaller tables, which are linked to each other. In this way the same information can be used many times over. That saves disk space, and makes updating information faster and more accurate. As you might expect, Qudos 3 is a relational database. Technically, it is a MS SQL Server database and works with recent full and express versions of MS SQL Server.

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