Presentation on theme: "Standard Grade Databases. What is a Database? A database is made up of files, records and fields. A structured collection of similar information that."— Presentation transcript:
What is a Database? A database is made up of files, records and fields. A structured collection of similar information that can be searched and sorted.
What is a Database? A database can be stored on paper (manual) or on a computer (electronic). A program that is used for organising data on a computer is called a database package. Data is organised in a database as files, records and fields: A database is an organised, structured collection of similar information.
Files A file is a collection of records. Data in a database is saved on the computer as a data file and contains data on a particular topic e.g. a Films data file. Records A record is a collection of fields. A record is a collection of organised data on a particular person or item. Fields A field is a single item of information. A field is part of a record that holds a particular piece of data e.g. Surname. Files….Records…Fields?
Field Record Here is a sample record from a telephone directory data file made up of different fields: Mr. TitleForenamePostcodeTel. No. JohnSmith101 High Street AyrKA7 3KL01292 262626 Sample Fields Address SurnameTown
Databases are used by many types of business and organisations such as: Telephone Directory Police National Computer Inland Revenue Driver and Vehicle Licensing Centre A personal Christmas card list A mailing list Data held in a database can be shared between other computer packages such as a word processor package – e.g. Mail Merge. What is a Database used for?
Records can be processed quickly. Records can be processed accurately. Information is immediately available. All of this is impossible in a manual system !!!! Advantages of an electronic database?
Databases have many of the features common to a general purpose package. There are some special features of a database: Create fields Add and alter records Search Sort Features of a Database?
The first step on setting up a database is deciding on the fields it requires. Fields hold the information you want to store. You can set the size and type of a field. Size: You can decide how many characters a field can hold e.g. a Postcode field to hold KA18 3GH would require a minimum of 8 characters as the space counts as a character! Type: Fields can hold different types of data: A text field holds letters. A number field holds only numbers. Date and time fields hold numbers formatted into date and time. Create Fields
The next step is to enter records into the empty database. A new record has to be created for each item. e.g. MrJohnSmith1 Anytown Scotland 01929 393939 MrsSusanJones5 The Town Scotland 01521 447210 Add and Alter Records Record 1 Record 2
e.g. search for the forenames and surnames of people whose test mark was greater than 50. You can run a search on a database for specific information. You can search on a field (or fields) based on certain conditions you require. Search Records
Sorting allows you to organise records into a particular order: alphabetic numeric ascending (1,2,3,4,5…) descending (Z, Y, X, W …) The sort is done by choosing which field the database is to be sorted into e.g. sort alphabetically by surname. Sort Records
Reports any information printed out from a database is a report. you can search for information, then sort it into an order, and decide what fields you wish printed out in what order. this is known as a report definition. Additional features of a Database
Example: If a database has the fields and, then a third called could be set up with the formula: (=Total Pay – Total Deductions). This is a computed field. A computed field (also called a calculated field) can be created in a database or report. It carries out a calculation on a field or fields and returns an answer (similar to a spreadsheet formula in a cell). Computed Fields
You can decide how the information in your database is presented by altering the format. You can change the way the input screen looks and format a report for output. The position of fields can be rearranged and formatted into a particular order and layout. This is useful for designing input screens and producing documents such as invoices for output. Altering Input/Output formats
Use of Keywords When searching for a particular record or part of it, the text that is used for the search is called a keyword. It is also known as a search string. However, care must be taken that the correct keywords are used. Keywords
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