Data is a useful information Which helps to make a decision Set of information of any entity is known as data Databases support storage and  manipulation of data

1. SQL (Data Base)

2. Data is a useful information.
Which helps to make a decision.
Set of information of any entity is known as data.
Example:
Employee information.(Name,job,sal etc…)
Product information
Sales information
• What is Data?

3. •What is Database ?
Place where you store data
A database is a systematic collection of data.
Databases support storage and manipulation of data.
Databases make data management easy.
Ex:
An online telephone directory.
Electricity service provider
Facebook.

4. • What is a Database Management
System (DBMS)?
Database Management System (DBMS) is a collection of
programs which enables its users to access database,
manipulate data, reporting / representation of data .
Data base combined with management system services is
known as DBMS.

5. Oracle 2,
 Oracle 3,
Oracle 4,
Oracle 5,
Oracle 6,
Oracle 7,
Oracle 8i,
Oracle 9i,
Oracle 10g,
Oracle 11g
and the latest to hit the market is Oracle 12c. here ‘i’ stands for Internet, ‘g’ stands for Grid /
Grid computing and C for Cloud Computing .
• Here the services are.
Entering new data
Updating old data with new data
Deleting unwanted data
Authenticating the users
Providing security
• The s/w which is widely used today is Oracle.
• The different versions of Oracle starting from the earliest to the latest are –

6. •What is Relational Database?
 It is the collection of relations or two dimensional tables
 Dr E.F Codd proposed the relational model for database system in 1969
 Relational Model Consists of following
 Collections of Objects or Relations
 Set of Operators to act on the relations
 Data integrity for accuracy and consistency.
( Data integrity is the one which contains correct data in the database)
 To restrict storing wrong data in database we use data integrity.
 To Preserve data integrity we have two types
1.DataType:
2.Constraints:
Data Type is a type of data which you store in each column.

7. A constraint is a condition which restricts the invalid data in the table.
A constraint can be provided for a column of a table.
•Constraints
A constraint is a condition which restricts the invalid
data in the table.
A constraint can be provided for a column of a table.
•Types of Constraints
 NOT NULL
 UNIQUE
 Primary Key
 Foreign Key
 Check

8. • Null
 NULL is nothing, it is neither zero nor blank space
 It will not occupy any space in the memory
 Two NULLS are never same in Oracle
 NULL represents unknown value
 Any arithmetic operation we perform on NULL will
result in NULL itself. For ex, 100000 + NULL = NULL ;
100000 * NULL = NULL

9. •Not Null
 NOT NULL will ensure at least some value should
be present in a column
• Unique
It will not allow any duplicates in a column
UNIQUE column can take multiple NULL (s)

10. • Primary Key
It is the combination of NOT NULL and UNIQUE
Only one PK is allowed in a table
PK identifies a record uniquely in a table
Creation of PK is not mandatory, but it is highly
recommended to create
Candidate Key: Eligible to become PK
Alternate Key: Eligible to become primary key but not chosen
as PK
CK=PK+AK
AK=CK-PK

11. • Foreign Key
FK creates relationship between any two tables
FK is also called as referential integrity constraints
FK is created on the child table
FK can take both NULL and duplicate values
To create FK, the master table should have PK defined on the
common column of the master table
We can have more than 1 FK in a given table

12. •Check
It is used to provide additional validations as per the
customer requirements.