MYSQL
It is freely
available open source Relational Database Management System (RDBMS) that uses
Structured Query Language(SQL). In MySQL database , information is stored in
Tables. A single MySQL database can contain many tables at once and store
thousands of individual records.
SQL
(Structured Query Language)
SQL is a language that enables you to create and operate on
relational databases, which are sets of related information stored in tables
DIFFERENT
DATA MODELS
A data model refers
to a set of concepts to describe the structure of a database, and certain
constraints (restrictions) that the database should obey. The four data model
that are used for database management are :
1.Relational data
model : In this data model, the data is organized into tables (i.e. rows
and columns). These tables are called relations.
2. Hierarchical
data model
3. Network data model
4. Object Oriented
data model
RELATIONAL
MODEL TERMINOLOGY
1. Relation : A table storing logically related data is
called a Relation.
2. Tuple : A row of a relation is generally referred to as a
tuple.
3. Attribute : A
column of a relation is generally referred to as an attribute.
4. Degree : This
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 within the relation.
7.Candidate Key : All attribute combinations inside a
relation that can serve as primary key are candidate keys as these are
candidates for primary key position.
8. Alternate Key : A candidate key that is not primary key,
is called an alternate key.
9. Foreign Key : A non-key attribute, whose values are
derived from the primary key of some other table, is known as foreign key in
its current table.
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