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Database, tables, records and fields
This chapter explains what is database, tables, records and fields.
What is a Database ?
A database is a collection of all data required for an application. Each database application will have only one database.
What is a Table ?
- Tables are part of database.
- A database is composed of several tables.
- You need to create separate tables to store different type of data. For examples, if you have a School Management Software, you may need to create the following tables:
- Students - to store list of all students
- Teachers - to store list of all students
- Attendance - to track the attendance of all students
- MarkList - to store the mark list of all students
What is a Record?
A record represents one entry in a Table. A table can have any number of records.
If you have a "Students" table to store the student information, a record in the table represent a student. To add a student, you will add a record to the "Students" table. To delete a student from the software, you will delete a record from this table.
What is a Field ?
A field is a column in the table. A record is a collection of fields. All records in the same table will have the same set of fields.
If you have the "Students" table, you may have the following fields:
Name - to store the name of the student
Address - to store the address
DateofBirth - to store the date of birth of the student
RegistrationDate - to store the date on which the student registered.
etc.
If you add a field to the Table, it is applicable to all records in the same table. In the above example, all records in the "Students" table will have the same 4 fields.
Summary
A database a collection of Tables
A Table is a collection of Records.
All records in the same table will have the same fields.
In most cases, an application will have one database which has several tables.
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