Here are some important terms used in relational database:
1. Relation: A table sorting logically related data is called a relation.
2. Tuple: A row of a relation is generally referred to as a tuple in database.
3. Attribute: A column of a relation is generally referred to as an/a attribute/field.
4. Degree: The degree of a table refers to the number of attributes in a relation.
5. Cardinality: This refers to the number of tuples in a relation.
6. Primary Key: This refers to a set of one or more attributes that can uniquely identify tuples in a relation.
7. Candidate Key: All possible combinations of attributes that can serve as a primary key for a relation are called candidate keys (as they are candidates of the primary key position).
8. Alternate Key: A candidate key which is not a primary key is called a alternate key.
9. Foreign Key: When an attribute in a table, which was the primary key for some other table, acts like a link between the two tables, is called a foreign key.
10. Referential Integrity: A set of rules that a DBMS uses to ensure the validity of relationships between related records as well as the security of the related data from accidental deletion, is called Referential Integrity. This integrity is ensured by a Foreign Key.
These were some important terms you need to know before moving on to learning SQL.
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This article is a part of our MySQL Tutorial for Beginners Series.
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