What are the key concepts of a relational database?
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What are the key concepts of a relational database?
In a relational database, all data is held in tables, which are made up of rows and columns. Each table has one or more columns, and each column is assigned a specific datatype, such as an integer number, a sequence of characters (for text), or a date. Each row in the table has a value for each column.
What are the 3 basic relationships in relational database?
There are 3 different types of relations in the database:
- one-to-one.
- one-to-many, and.
- many-to-many.
What are the four main elements in a relational database?
Elements of a relational database
- Tables.
- Rows.
- Columns.
- Keys.
- Indexes.
What is a key and how is it important in a relational model?
Keys are very important part of Relational database model. They are used to establish and identify relationships between tables and also to uniquely identify any record or row of data inside a table. A Key can be a single attribute or a group of attributes, where the combination may act as a key.
What are the different types of keys in DBMS?
Keys are of seven broad types in DBMS:
- Candidate Key.
- Primary Key.
- Foreign Key.
- Super Key.
- Alternate Key.
- Composite Key.
- Unique Key.
What are the six major elements of a database?
The Elements of a Database
- The database schema.
- Schema objects.
- Indexes.
- Tables.
- Fields and columns.
- Records and rows.
- Keys.
- Relationships.
Why keys are important in relational database?
Keys are a major component of table-level integrity and relationship-level integrity. For instance, they enable you to ensure that a table has unique records and that the fields you use to establish a relationship between a pair of tables always contain matching values. They serve to establish table relationships.
