An appropriate data type, is attached to the field name in a database, In total there are, 11 data types, Text means, text and data that is a mix of text and numbers e.g. postcode, Number means, numeric data that requires a mathematical calculation, Date/Time, Stores a date or time, Currency, Monetary value such as item price and includes 2 decimal places, Autonumber, Automatically stores a numeric value that is one greater than that in the last record added, Yes/No is also called, Boolean, Yes/No, used to store data that has only two possible values such as yes or no, true or false, and on or off., OLE object, contains an object created by another software package e.g. Excel workbook, Hyperlink, An address that links to another location, such as a website (URL), email address or an external file., Attachment, Files attached to a record, e.g. digital image, Calculated, For the result of a calculation produced from another field in the record, Lookup Wizard, creates a list of values and allows user to select a value from the list and enter into the field, Data validation is, the process of verifying that a program's input data is within the expected range, Data validation guarantees that data is, present, the correct type, range or length, Data that doesn't conform to specified rules, is rejected, The data validation checks are, presence, length, type, format and range, If data is rejected, an error message is displayed and a reason given, A presence check ensures, data is present and does not allow a space to be left blank, Presence checks are mainly used in, online forms, Validation rule for presence requires, "Required" set to "Yes" for the field required, A length check ensures, data entered is the correct number of characters, An example of using length check is, a customer number must contain 6 characters, A type check is used to ensure, data entered is of the correct type, There are several "types" including, numeric, text and date, A format check ensures data entered, matches a predetermined pattern, An example of format check is, a postcode which would have a pattern such as BTXX XXX, A range check ensures data entered, is within a lower and upper limit e.g. between 1-10, Logical operators, compare a value against another e.g. less than (<), less than or equal to (<=), greater than (>) etc.

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