All About Access Objects

	Access databases are made up of objects that: store your data allow you to enter data allow you to view data allow you to ask questions about the data in your database and present your data in easily understood format

Object Types

The four primary object types in an Access database are:

tables
forms
queries
reports

Tables

These objects are used to store your data in the database. Tables consist of

fields which store a specific piece of information (name, address, city, state, zip, and so forth)
records which represent a complete set of information on a specific entity

Remember that a Database File is a

collection of records (a stack of electronic 3x5 cards)
a record (the electronic 3x5 card) consists of one or more fields
a field is a category of information (the “blanks” to be filled in)

In Access, these items are stored in a Table. Thus a table represents a collection of records that describe similar data. In a flat-file database, you most likely would have all data stored in a single Access table. In a relational database, you would most likely have more than one table with a relationship set to tie or link the two (or more) tables of data.

Forms

These are the objects used to input data into tables as well as view your records one at a time. Although you can enter data directly into a table, forms provide a user-friendly interface for data input, editing, and review.

Forms are made up of controls. Controls are items on the background of a form. By definition a control represents any object in a form (or a report). Controls are so named because they control where you can enter or review the data in your tables. Some of the controls available are:

labels are used to identify sections of a form and/or to offer instructions for data input
text boxes are used to enter comments
option buttons permit users to enter yes/no type questions with a simple mouse click
toggle buttons permit users to enter yes/no type questions with a simple mouse click
check boxes permit users to enter yes/no type questions with a simple mouse click
list boxes present users with a preset list of values in a drop-down list from which to select
combo boxes present users with a preset list of values in a drop-down list from which to select

Queries

Queries are tools that are used to ask questions about the contents of your database. Queries may be used to find records from within a single table as well as to combine information from two or more related tables into a single object. Queries may also be used to perform calculations on the selected information.

The results of a query are called a dynaset (for “dynamic set” of records) because the collection of records changes as the query changes. These changes do not affect the data in the source tables!

When you design a query, you

specify which tables you wish to use as a data source
specify which field(s) from those tables contain the information you desire
set the criteria for each field so that the query will find the desired information

For example, suppose you needed to determine which students were eligible for a particular honorary society. The criteria is all students who have had a minimum of three courses in the department in question with a grade of B or better and an overall GPA of 3.0. Your query would use this criteria and specify the table(s) that contained the information of the students.

There are a variety of query types available in Access including:

Select Queries which find and display the data requested (the basic type of query)
Parameter Queries are similar to select queries but they prompt you for the criteria to use when selecting data
Crosstab Queries generate spreadsheet-like output based on data from three or more fields
Delete Queries find records and deletes them (be careful with this one!)
Update Queries find records and changes one or more values in one or more fields

Reports

Reports are used to create a more sophisticated and complicated (and perhaps better organized!) view of your data than can be done with a table or datasheet. Reports can be used to

present the contents of your tables and queries
perform calculations on the contents of database objects
print formatted things such as address labels

While a form is the input mode for an Access database, a report is the output mode. Forms permit you to input data via an easily understood interface. Reports present that information in an easy-to-read and well-organized format. Reports are generally used when you need to print the results from queries.

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