Data is organized in a data storage
hierarchy of increasingly complex levels: bits, bytes (characters), fields,
records, files, and databases. A character is a letter, number, or special
character. A field consists of one or more characters (bytes). A record is a
collection of related fields. A file is a collection of related records. A
database is, as mentioned, an organized collection of integrated files.
Important to data organization is the key field, a field used to uniquely
identify a record so that it can be easily retrieved and processed.
Introduction to database
- · Data definition language contains statements that help you define the database and its objects e.g., tables, views, triggers, stored procedures, etc.
- · Data manipulation language contains statements that allow you to update and query data.
- · Data control language allows you to grant the permissions to a user to access a certain data in the database.
What is Table ?
In Relational database, a table is a collection of data elements organised in terms of rows and columns. A table is also considered as convenient representation of relations. But a table can have duplicate tuples while a true relation cannot have duplicate tuples. Table is the most simplest form of data storage. Below is an example of Employee table.
What is a Record ?
What is Field ?
What is a Column ?