Database
Actually, we have learned about Database. Database is a
collection of interrelated data stored together with controlled redundancy to
serve one or more applications in an optimal way. The data are stored in such a
way that they are independent of the programs used by the people for accessing
the data. I also have learned about database Components which are data item,
relationship, constraints and schema, database management systems and examples
of database management system such as Microsoft Access, Oracle, or MySQL.
After that we moved to DBS, DBS is The DBMS software
together with the Database is called a database system. It can be defined as an
organization of components that define and regulate the collection, storage,
management and use of data in a database. It is a system whose overall purpose
is to record and maintain information.I also have learned some types of
database models which are Hierarchical database, Network database, relational
database and object-relational database,
my lecturer explained one by one models.
Then we moved to
Database terminology, there are some terms such as Field,
Record, Table, Key field, Relational database , and Objects
, as well as she explained each terms.
Field: A specific piece or category of data such as a first
name, last name, city, state, subject or birth date.
Record: A group of related fields that describes a person,
place, thing or transaction such as customer, student, location, product, or
sale.
Table: A collection
of records for a single subject such as Students, Products, or Sales.
Key field: A field that
contains unique information for each record, such as student ID for a student.
Relational database:
Multiple tables that are linked together to address a business process such as
managing timetable, courses, and students.
Objects: The parts of an Access database that help you view,
edit, manage, and analyze the data: tables, queries, forms, reports, macros,
and modules.
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There are 3 types of Database Language
- -- DDL (Data
Definition Language)
- -- DML (Data
Manipulation Language)
- -- DCL (Data
Control Language)
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The basic block for data models are:
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- - Entity
- - Attributes
- - Relationship
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Entity- represents a particular object in the
real world (a person, a place or an event). For e.g., student information
system: subject, student, course, time table.
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Attributes- it is the characteristics of entity
that represent by column in table.
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Relationship- it describes the relationship
among entities. It can be describe in a form of diagram, called ERD ( Entity
Relationship Diagram).
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There are 3 forms of ERD:
- - One to One (1:1)
- - One to Many (1:M)
- - Many to Many (M:M)
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