Basic SQL
Ram Kumar
About Me
My Self Ram Kumar I have 15 Years of extensive knowledge
in database and currently I am associated with Allscripts.
Skill : Oracle Database 10g/11g/12c/19c/21c
Oracle Forms and Reports 6i/10g/11g/12c
Postgres 9.2/9.3/9.4/10/11
Java Spring MVC, Oracle ADF etc.
Qualification : MCA
Language : English & Hindi
☏ Mobile – +91-9220970607
✉ Email – ram5393@gmail.com
About Database/RDBMS/Table/Column
What is different Type of Database ?
What is SQL ?
Course
Outline
What are the Type of SQL Commands ?
What is Transactions ?
What is Constraints ?
What is View?
Comments
What is database?
▪ A database is an organized collection of data, so that it can
be easily accessed and managed.
▪ You can organize data into tables, rows, columns it to make it
easier to find relevant information.
▪ The main purpose of the database is to operate a large
amount of information by storing, retrieving, and managing
data.
▪ SQL or Structured Query Language is used to operate on the
data stored in a database.
About Database
Type of Database
SQL
Conclusion
What is RDBMS?
▪ RDBMS stands for Relational Database Management System.
▪ All modern database management systems like SQL, MS SQL Server, IBM DB2,
ORACLE, My-SQL, and Microsoft Access are based on RDBMS.
▪ It is called Relational Database Management System (RDBMS) because it is based on
the relational model introduced by E.F. Codd.
▪ Data is represented in terms of tuples (rows) in RDBMS.
▪ A relational database is the most commonly used database. It contains several tables,
and each table has its primary key.
About RDBMS
Type of Database
SQL
Conclusion
Overview of Tables in SQL
▪ Tables are the fundamental way to store data in a
relational database management system. It
contains a header row at the top of the table, which
gives the list of column names, followed by rows
that contain data.
Below is the Employee Table
▪ In simple terms, it’s a collection of related data held
in a table format.
Fields/Column in SQL
▪ Fields are basically columns in a table with specific
information about the data.
Records/Data in SQL
▪ A record is basically an individual entry that exists
in a table. Records give complete information about
a single entry or entity
About Table
Type of Database
SQL
Conclusion
What is Normalization
▪ Normalization is a database design technique that
reduces data redundancy and eliminates undesirable
characteristics like Insertion, Update and Deletion
Anomalies.
▪ Normalization rules divides larger tables into smaller
tables and links them using relationships.
▪ The purpose of Normalization in SQL is to eliminate
redundant (repetitive) data and ensure data is stored
logically.
Why SQL
Type of Database
SQL
Conclusion
Tools to Connect Database
▪ SQL*Plus is a software tool with an interface into which
you can type SQL and SQL*Plus commands and monitor
their execution. This is inbuild no need any external
installation.
▪ SQL Developer - Oracle SQL Developer is a free,
integrated development environment that simplifies the
development and management of Oracle Database.Its
GUI Based so working with it is simple compared to SQL
Plus.
SQL Tools
Type of Database
SQL
Conclusion
Why should you learn SQL?
▪ SQL is an easy-to-learn language specifically designed to
work with databases.
▪ There is a growing demand for professionals who can
handle databases like Software Engineer ,Business
Analyst ,Data Scientist etc.
▪ Almost every big company is using SQL. It is widely used
in various sectors like ticket booking, banking, social
media platforms, data sharing, eCommerce etc.
▪ It is used in data systems such as MySQL, PostgreSQL,
Oracle and many others.
Why SQL
Type of Database
SQL
Conclusion
Type of Database
SQL
No SQL.
SQL is a relational database management system.
The query language used in this database system is
a structured query language. The schema of SQL
databases is predefined, fixed, and static.
The database type of SQL is in the form of tables,
i.e., in the form of rows and columns. SQLite, SQL
Server, Oracle, PostgreSQL, and MySQL are
examples of SQL database systems.
No-SQL is a non-relational database management
system. The query language used in the No-SQL
database systems is a non-declarative query language.
The schema of No-SQL databases is a dynamic schema
for unstructured data. The database type of No-SQL is
in the form of documents, key-value, and graphs.
Redis, MongoDB, Hbase, BigTable are examples of
NoSQL database systems.
Why SQL
Type of Database
SQL
Conclusion
What is SQL ?
SQL is Structured Query Language which
help to manage databases. it helps
Database Creation, Database Deletion,
Fetching Data Rows, Modifying &
Deleting Data rows, etc. It is also the
standard language used in the Relational
Database Systems. Various Relational
Database Systems like MySQL, Sybase,
Oracle, MS Access, Postgres, Infomix, SQL
Server, etc., have SQL as their base
language.
Why SQL
Type of Database
SQL
Conclusion
Data Type
Data Type define the value that column is going to store.
Oracle supplies the following built-in datatypes:
▪ CHARACTER Datatypes
CHAR - > Fixed for every row in the table maximum size is 2000 bytes per row,
Varchar2 -> Variable for each row, up to 4000 bytes per row.
Long -> Maximum size of 2GB.
▪ NUMBER Datatype
Number -> Storing numeric value Number(Precision,Scale)
▪ DATE Datatype
Date -> Storing Date Field
▪ Binary Datatype
BLOB -> Store up to 4GB of binary data. Stores unstructured binary large objects. Ex Image, Video & Audio
CLOB -> Store up to 4GB of character data. Stores single-byte and multi-byte character data. Ex- XML data
BFILE -> Maximum file size of 4GB. Unlike BLOB and CLOB types, BFILE data type does not store the binary file
itself but stores the address (file system path) of the file. Therefore, it is suitable for storing large binary files such
as images, audios, videos, etc., to reduce the storage burden on the database server.
Why SQL
Type of Database
SQL
Conclusion
What is Transaction ?
A transaction is the logical work unit
that performs a single activity or
multiple activities in a database.
Transactions may consist of a single
read, write, delete, or update operations
or a combination of these.
COMMIT or ROLLBACK TRANSACTION
Apply data changing to the database or
Erase data changing to the database
Why SQL
Type of Database
Transaction
Conclusion
DDL
DML
SQL Command
DQL
TCL
DCL
Why SQL
Type of Database
Data Definition Language
DDL is used to define the structure or
schema of the database.
Some of the DDL commands are as
follows :
1. Create: to create objects in the
database
2. Alter: alters the structure of the
database
3. Rename: rename an object
4. Truncate: deletes all the data stored
in a table
5. Drop: delete objects from the
database
DDL
Conclusion
DDL
SQL Command
DML
DML is used for managing data
contained in the schema objects.
DQL
Some of the DML commands are as
follows :
TCL
DCL
Why SQL
Data Manipulation Language
Type of Database
1. Insert: used to insert data in the
database
2. Update: used to modify the existing
data in the database
3. Delete: used to delete all/Limited
records in the database.
4. Merge: used to merge two or more
tables or rows.
DML
Conclusion
DDL
DML
SQL Command
DQL
TCL
DCL
Why SQL
Type of Database
Data Query Language
DQL is also known as the Data Query
language. It is used to retrieve the data
stored in the database created by us and
the data we store in the database.
Syntax:
Select * from table Name ;
After executing this command, we can
view all the columns and all the data
stored in the table.
Example:
Select * from employee : helps in viewing
all the data i.e., all rows and columns.
DQL
Conclusion
Transaction Control
Language
DDL
DML
SQL Command
Why SQL
DQL
TCL also know as Transaction Control
Language .TCL commands are used to handle
transactions in the database.
These are used to manage and track the
changes made by DML statements , these can
be grouped together into logical transactions.
Example:
1. Commit: used to permanently save any
transaction into the database.
TCL
2. Rollback: used to restore the database to the
last committed state and is also used with the
Savepoint command to move over to any saved
state in a transaction.
DCL
3. Savepoint: It is used to temporarily store a
transaction so that we can move to the point
we need whenever desired.
Type of Database
TCL
Conclusion
SQL Command
DDL
Data Control Language
DML
DCL also know as Data Control
Language which includes commands such as
GRANT and mostly concerned with rights,
permissions and other controls of the database
system.
DQL
TCL
DCL
Why SQL
Type of Database
While using DCL commands, we need to be
cautious as some database’s don’t allow
rollback command on the DCL command. One
such example is the Oracle database .
Example :
1. Grant: allow users access privileges to the
database.
2. Revoke: withdraw users access privileges
given by using the GRANT command.
DCL
Conclusion
Create User
Use the CREATE USER statement to create and configure a database user, which is an account through which
you can log in to the database, and to establish the means by which Oracle Database permits access by the
user.
Prerequisites
You must have the CREATE USER privileges.
Syntax :- CREATE USER SCOTT IDENTIFIED BY tiger;
select * from all_users;
GRANT ALL PRIVILEGES TO HR;
DROP USER SCOTTNEW CASCADE;
Why SQL
Type of Database
Constraints
Conclusion
DCL(Grant / Revoke)
Grant is used to grant privileges on tables, view, procedure to other users or roles. ExSuppose you own emp table. Now you want to grant select and insert privilege on this table to another user “HR”.
Grant select, insert on emp to HR;
Suppose you want to grant all privileges(Select ,Insert ,Update ,Delete ,Alter ) on emp table to HR. Then
Grant all on emp to HR;
Revoke is used to revoke privileges already granted to other users.
Example to revoke select and insert privilege you have granted to HR then give the following statement.
Revoke select, insert on emp from HR;
To revoke All privileges on emp granted to HR give the following command.
Revoke ALL on emp from HR;
Why SQL
Type of Database
Constraints
Conclusion
Information About Privileges
To see which table privileges are granted by you to other users.
Select * from user_tab_privs_made;
To see which table privileges are granted to you by other users
Select * from user_tab_privs_recd;
To see which column level privileges are granted by you to other users.
Select * from user_col_privs_made;
To see which column level privileges are granted to you by other users
Select * from user_col_privs_recd;
Why SQL
Type of Database
Constraints
Conclusion
What is Constraints ?
Constraints are the rules that we can apply on the type of data in a table. That is, we can specify
the limit on the type of data that can be stored in a particular column in a table using constraints.
List of constraints are
NOT NULL- This constraint tells that we cannot store a null value in a column.
UNIQUE - This constraint when specified with a column, tells that all the values in the column
must be unique.
PRIMARY KEY - A primary key is a field which can uniquely identify each row in a table.
FOREIGN KEY - A Foreign key is a field which can uniquely identify each row in another table.
CHECK - This constraint helps to validate the values of a column to meet a particular condition.
DEFAULT - This constraint specifies a default value for the column when no value is specified by
the user.
Why SQL
Type of Database
Constraints
Conclusion
What is View ?
A view contains rows and columns, just like a real table. The fields in a view are fields
from one or more real tables in the database.
You can add SQL statements and functions to a view and present the data as if the data
were coming from one single table.
Example CREATE VIEW view_name AS
SELECT column1, column2, ...
FROM table_name
WHERE condition;
A view always shows up-to-date data! The database engine recreates the
view, every time a user queries it.
Why SQL
Type of Database
View
Conclusion
SQL Comments
Single-line comments :- Comments starting and ending in a single line are considered single-line comments.
A line starting with ‘–‘ is a comment and will not be executed.
Syntax :- -- single line comment
Select * from Employee. – This Query will fetch data from Employee table.
Multi-line comments :- Comments starting in one line and ending in different lines are considered as multiline comments.
A line starting with ‘/*’ is considered as starting point of the comment and is terminated when ‘*/’ is
encountered.
Syntax:- Select * from employee.
/* This will get the data from
employee table.
*/
Why SQL
Type of Database
Comment
Conclusion
Here is what we learned
▪ SQL
▪ Type of Database
Summary
▪ SQL Command (DDL,DML,DQL,DCL)
▪ Transaction
▪ Constraints
▪ View
▪ Comments
Conclusion