Microsoft Access '97 – 2003 | Page Four | The Access Glossary
This page describes some of the many terms used in the design of a database using Microsoft Access, spanning Tables, Queries, Forms and Reports.
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A-Z
Asterisk
Star symbol/character above the eight on a standard keyboard (See Wild Card).
Attribute
An attribute of an Entity (Table) would be a Field. An attribute of a Record, however, would be Data (See Information).
Batch Processing
An attribute of an Entity (Table) would be a Field. An attribute of a Record, however, would be Data (See Information).
Controls
See Data Controls.
Criteria
See Criterion.
Criteria Expression
See Operator.
Criterion
Criteria a comparison. A query search, for example, must match this (See also Operator).
DBA
Database Administrator… A person who is responsible for designing, maintaining and implementing change to a database.
Data
Data is a piece of information. Peterborough for example, makes up part of an address (See Record).
Data Controls
A means of implementing and controlling the way in which data is entered. A Post Code for example. See Field Properties. Types of data controls, found in the Field Properties section in Design View, include Default Value; Validation Rule, and Validation Text.
Data Types
DataType determines what values can be stored in a field.
Default
A pre-set action; perhaps where there is no specific command. Example An application may open a blank (New) document by default, albeit you may opt to close this document, opening an existing (Current) file.
Default Value
Automatically add a certain value for a field when a new record is added.
Data Dictionary
An essential part of the database design process is to maintain a data dictionary. Its main function is to store details of all the data items in a database. Such details can be wide ranging, but should include as a minimum
- Field names and tables that hold the data.
- Field definitions including field types and lengths.
- Additional properties concerning data formats and validation.
- Synonyms, where the same field is replicated in more than one table with a different name. Using synonyms, however, is not considered good practice.
Decimal Places
Displays a certain number of places after the decimal point, for Number fields only.
Definition
a) A brief description of what is held in a Field (See Data Dictionary).
b) Also, the meaning of; operator for example, e.g. the definition of an Operator.
Entity
A name given to a table within a database file, e.g. Doctor; Patients…
Expression
See Operator.
Field
Examples
- Start date; Position; Dept; Salary etc.
- Name; Address1; Address2; Town or City; Post Code etc.
Field Properties
Examples
- Field Size, up to 255 characters.
- Input Mask, a pattern controlling the data entered into a field, e.g. Telephone No (01733) 123456. This would be entered in zeros or nines (excluding the inverted comma) as '(00000) 717193' in the Input Mask area. However, here we must set the DataType to Text. A Wizard facility is optional by clicking to the right of the Input Mask text area.
- Default Value, a value entered into the table automatically, e.g. a date Date()
- Validation Rule, a rule to ensure data entered complies with, otherwise will not be accepted.
- Validation Text, your error message associated with the Validation Rule, which is displayed if criteria does not match this rule.
Field Size
Field size determines the size of a field, or limits the range of allowable values in a Number field.
Format
Displays dates and numbers in a specific format, such as Long Date Format or Currency Format.
Formulae
Formula, a mathematical expression (See also Function).
Function
As for Formulae, functions are prevalent to more advanced operators (users), or Access programmers perhaps. However, some might be referring to Criteria Expressions or Operators when using this term (See Operator).
Information
Any number of data items collectively making up information (A record) in a table (See also Data, Field, and Record).
Input Mask
Restricts entry of data to a specific pattern. Can also convert text to upper or lower case, and automatically display additional characters.
Operator
Equal to, for example, is the definition of = (the Operator (Comparison)). Others < (Less than); > (Greater than). When coupled with Criteria, this is referred to as a Criteria Expression, e.g. =£100.00.
Primary Key
Relevant to a unique field. Where there are two or more related tables (See Relationship), the unique field must have a Primary Key to ensure values are not duplicated.
Real Time Processing
Data that is processed immediately, at point of contact (See Batch Processing).
Record
A collection or string of data make up information (A record) in a table; an address perhaps. Fields are required to make up a record (See also Data, Field, and Information).
Relationship
A relational database system encompasses more than one table with related information. Tables must have a unique field (Primary Key). Example A personnel table need not include staff contact details. This information can be maintained in a separate table, therefore only a relationship with the Personnel table exists. There may be any number of reasons why you might want to do this. You might like to retain contact details of employees who are no longer in the personnel table for example. More importantly perhaps, not to replicate data/batch processing.
String
A collection of words…
User
The individual or operator, the person who uses the computer… Not operator as in Criteria Expression.
Wild Card
An asterisk with criteria would be used to return any result. For example 'Like Smyth' would only return the name 'Smyth'. However 'Like Sm*' would also return 'Smith' and 'Smiley' perhaps.
Wizard
A facility to take the user through any given function, step by step, simplifying process… See Input Mask in Field Properties.
