By default, the datatype of Microsoft Access is Text. You can change it to other data types according to your needs but you should be aware of their properties and differences between them. The names of some of the datatypes are as: Text, number, currency, memo, date/time, Yes/No, hyperlink, OLE, Autonumber. Below are the descriptions of above mentioned datatypes, which will help you out to choose which datatype to use:
Text: Use this datatype when you think that your field will contain letters, combination of letters as well as numbers which will be never be calculated but not currency. E.g.: for address of a person/employee etc one can use the text datatype.
Number: This datatype is used where entered numbers can be stored numerically, indexed and where the numbers will be calculated but the maximum accuracy is not so important.
Currency: If you think that your field will contain money and that there should be full accuracy in the calculations performed, you must use this datatype. It calculates the data fields up to 15 decimal points any are usually used where the calculations are the main concern.
Memo: This type of datatypes are used to go through extended notes as well as numbers but memo datatypes can’t be used for sorting or to index any kind of records and neither can be used for any kind of calculations
Date/Time: This type of datatype is used where one needs to enter data as dates and times. It is possible to enter date and time data in the where text datatype is used but will lack performance where the term sorting will come. So it’s better use this datatype to get a stable outcome.
Yes/No: This datatype is used in cases where user needs to or is forced to click on any one of the options given. It may be like: yes/no, off/on, true/false. Let’s take an example of employee records where in certain field employee’s marital status has to be disclosed. So in this case it will be either yes/no as an employee can be either married or unmarried.
Hyperlink: This datatype is used to skip to any preferred location of your database else to different location on your PC or directly to the web. This type of datatype can’t be calculated neither indexed nor can be sorted nor grouped.
OLE: This datatype is used to set in or link an object from another similar in temperament program; like-one can link a word document, picture, sound etc to a chart. This type of datatype can neither be grouped nor sorted nor indexed nor can be used for any calculation purposes.
Autonumber: This datatype is used to assign random numbers or sequential numbers to a field. The numbers in this type of datatype are used as primary keys and are used to set up common fields or a relationship between two or more tables. You can even assign the primary keys manually but using the AutoNumber will help you out to cut time as well as effort.