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. It covers terms used in the design of Tables, Queries, Forms and Reports.

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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:

Data that is processed periodically, at the end of the day perhaps, not in real time (See Real Time Processing).

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, for example, an Operator, 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 that is 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.

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