What is data?
In computing, information is processed data that has been translated into a form that is more convenient to move or process.It is organized,meaningful and useful. In today's computer and transmission media, data is information converted into binary digital form.
Data Type
The type of data in a field is an important consideration. The data type specifies the kind of data a field can contain and how the field is used. Common data type include text, numeric, currency, date, memo and hyperlink.
Data dictionary contains data about each file in the database and each field in those files. For each file, it stores details such as the file name, description, the file's relationship to other files and the number of records in the file. For each field, it stores details such as the field name, description, field type, field size, default value, validation rules, and the field's relationship to other fields.
Hierarchy of Data
Data Hierarchy
Data is organized in layers. In the computer profession, data is classified in a hierarchy. Each higher level of data consists of one or more items from the lower level. A database contains files, a file contains records, a record contains fields, and a field is made up of one or more character.
-FIELD
A group of characters. e.g. data held about a person may be split into many fields including ID Number, Surname, Initials, Title, Street, Town, etc
-RECORD
A group of fields holding all the information about one person or item
-FILE
A collection of records. A stock file will contain a record for each item of stock, and so on.
-DATABASE
May consist of many different files, linked in such a way that information can be retrieved from several files at once.