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Data Types

When you define a record structure, you need to specify what type of information will be stored in every field of the record. In the example table employees that holds employee information, employee name would be a field which holds the name as text and id would be a field which holds the employee id as a number and so on.

Data types define the type of information that will be stored in a field.

Simple Data types

Numeric A field that contains whole numbers only. Numbers without a fractional part
Decimal Fields with numbers that contain fractional parts
Text Text fields are typically used to hold textual information like names and addresses. But in practice they are used store any information represented as a sequence of characters
Boolean A boolean field can hold a logical True or False value and nothing else.
Date Date field contains a date value

Large Data types

Large Text A Large Text field can store multi line text data. Typically used to store notes, comments and even large documents.
Small Image This field can store an image, which can be captured from a TWAIN compatible source like a webcam or scanner. Alternately the image can be loaded from a file.

Special Data types

Auto Increment Holds a numeric value that is automatically incremented by one whenever a new record is added. An autoincrement field is guaranteed to be unique in a table making it a good choice as a primary key.
Link Typically used to build a relationship beween two tables. A link field holds a value which will act as the primary key to another table, thus linking the two tables together. In the example table employees, department information is stored in a separate table and the employee table has a link field that just contains the name of the department. This link field can be used to retrieve deparment information like location, number of employees, department type and so on. The link field will always result in a single match.
MultiItem A MultiItem Field defines a special relationship between two tables where the master table can refer to multiple records in the other table. For example one record in the departments table can refer to multiple employees who belong to the same department. A multiitem field will result in multiple matches.
Triggers Triggers are not fields at all, but special actions that are invoked when a new record is added. Typically used to create a new record or update an existing record based on a value entered in the current record.