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As per Term
wise
Syllabus
2021-22

Chapter 8
Database
Concepts

Computer Science
Class XII ( As per CBSE Board)
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DATABASE CONCEPTS
A Database is a collection of DATA/INFORMATION that is
organized so that it can be easily accessed, managed and
updated
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It works like a container which contains the
various object like Tables, Queries, Reports etc
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DATABASE CONCEPTS
WHY DO WE NEED DATABASE
 To manage large chunks of data: if size of data increases into
thousands of records, it will simply create a problem to
manage
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 Accuracy: Through validation rule in database ,data accuracy can
be maintained
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Moreover, multiple
people can also edit data at same time
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 Data integrity: In databases, we can be assured of accuracy and
consistency of data due to the built in integrity checks and access
controls
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mykvs
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❖ A Database along with DBMS software is called Database
System
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❖ MySQL is open source and freeware DBMS
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mykvs
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❖ Database controls Inconsistency
When two copies of the same data do not agree to each other, then it is called
Inconsistency
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❖ Database facilitate Sharing of Data
Data stored in the database can be shared among several users
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❖ Database maintains Integrity
It enforces certain integrity rules to insure the validity or correctness of data
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A date can’t be like 31/31/2000
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mykvs
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A data is modeled by one of
the following given❖ Relational Data Model
In this model data is organized into Relations or Tables (i
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Rows and Columns)
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A column is called
Attribute or Field
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❖ Hierarchical Data Model
In this model, Records are organized as Trees
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❖ Object Oriented Data Model
In this model, records are represented as a objects
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DATABASE CONCEPTS
RELATIONAL DATABASE
A relational database is a collective set of multiple data sets
organized by tables, records and columns
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Tables communicate and share information, which
facilitates data searcheability, organization and reporting
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DATABASE CONCEPTS
RELATIONAL DATABASE TERMS

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DATABASE CONCEPTS
RELATIONAL DATABASE TERMS
❖Relation (Table)
A Relation or Table is Matrix like structure arranged in Rows and Columns
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e
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❖ No duplicity: No two rows of relation will be identical i
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in any two rows
value in at least one column must be different
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e
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❖ Ordering of rows and column is immaterial
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❖ Tuple / Entity / Record - Rows of a table is called Tuple or Record
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❖ Degree - Number of columns (attributes) in a table
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DATABASE CONCEPTS
KEYS IN A DATABASE
Key plays an important role in relational database; it is used for
identifying unique rows from table & establishes relationship among
tables on need
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❖ Candidate Key –It is an attribute or a set of attributes or keys
participating for Primary Key, to uniquely identify each record in
that table
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❖ Foreign Key – Foreign keys are the columns of a table that points
to the primary key of another table
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DATABASE CONCEPTS
KEYS IN A DATABASE

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