UNIT – I

1. DATA BASE MANAGEMENT SYSTEM (DBMS)

What is Database

The database is a collection of inter-related data which is used to retrieve, insert and

delete the data efficiently. It is also used to organize the data in the form of a table, schema,

views, and reports, etc.

For example: The college Database organizes the data about the admin, staff, students and

faculty etc.

Using the database, you can easily retrieve, insert, and delete the information.

Database Management System

o Database management system is a software which is used to manage the database. For

example: MySQL, Oracle, etc are a very popular commercial database which is used

in different applications.

o DBMS provides an interface to perform various operations like database creation,

storing data in it, updating data, creating a table in the database and a lot more.

o It provides protection and security to the database. In the case of multiple users, it also

maintains data consistency.

DBMS allows users the following tasks:

o Data Definition: It is used for creation, modification, and removal of definition that

defines the organization of data in the database.

o Data Updation: It is used for the insertion, modification, and deletion of the actual

data in the database.

o Data Retrieval: It is used to retrieve the data from the database which can be used by

applications for various purposes.

o User Administration: It is used for registering and monitoring users, maintain data

integrity, enforcing data security, dealing with concurrency control, monitoring

performance and recovering information corrupted by unexpected failure.

Components of DBMS

Users: Users may be of any kind such as DB administrator, System developer or database

users.

Database application: Database application may be Departmental, Personal, organization's

and / or Internal.

DBMS: Software that allows users to create and manipulate database access,

Database: Collection of logical data as a single unit.

Characteristics of DBMS

o It uses a digital repository established on a server to store and manage the

information.

o It can provide a clear and logical view of the process that manipulates data.

o DBMS contains automatic backup and recovery procedures.

o It contains ACID properties which maintain data in a healthy state in case of failure.

o It can reduce the complex relationship between data.

o It is used to support manipulation and processing of data.

o It is used to provide security of data.

o It can view the database from different viewpoints according to the requirements of

the user.

DATABASE SYSTEM APPLICATIONS

Database system are widely used and the various applications are

1. Banking- storing customer information, accounts, loans, etc.

2. Airlines-to store reservation and scheduling information.

3. Universities- storing student information and course registration.

4. Finance- for storing information about holding, sales, etc.

5. Telecommunication- for keeping records of calls made, generating monthly

bills, etc.

6. Human resources- for information about employees, salaries and payroll taxes,

etc.

Advantages of DBMS

o Controls database redundancy: It can control data redundancy because it stores all

the data in one single database file and that recorded data is placed in the database.

o Data sharing: In DBMS, the authorized users of an organization can share the data

among multiple users.

o Easily Maintenance: It can be easily maintainable due to the centralized nature of the

database system.

o Reduce time: It reduces development time and maintenance need.

o Backup: It provides backup and recovery subsystems which create automatic backup

of data from hardware and software failures and restores the data if required.

o multiple user interface: It provides different types of user interfaces like graphical

user interfaces, application program interfaces

Disadvantages of DBMS

o Cost of Hardware and Software: It requires a high speed of data processor and large

memory size to run DBMS software.

o Size: It occupies a large space of disks and large memory to run them efficiently.

o Complexity: Database system creates additional complexity and requirements.

o Higher impact of failure: Failure is highly impacted the database because in most of

the organization, all the data stored in a single database and if the database is damaged

due to electric failure or database corruption then the data may be lost forever.

2. RELATIONAL DATABASE MANAGEMENT SYSTEM (RDBMS)

RDBMS stands for relational database management system. A relational model can be

represented as a table of rows and columns. A relational database has following major

components:

1. Table

2. Record or Tuple

3. Field or Column name or Attribute

4. Domain

5. Instance

6. Schema

7. Keys

8. Null Value

9. Data Integirty

1. Table

A table is a collection of data represented in rows and columns. Each table has a name in

database. For example, the following table “STUDENT” stores the information of students in

database.

Table: STUDENT

Student_Id Student_Name Student_Addr Student_Age

101 Chaitanya Dayal Bagh, Agra 27

102 Ajeet Delhi 26

103 Rahul Gurgaon 24

104 Shubham Chennai 25

2. Record or Tuple

Each row of a table is known as record. It is also known as tuple. For example, the following

row is a record that we have taken from the above table.

102 Ajeet Delhi 26

3. Field or Column name or Attribute

The above table “STUDENT” has four fields (or attributes): Student_Id, Student_Name,

Student_Addr & Student_Age.

4. Domain

A domain is a set of permitted values for an attribute in table. For example, a domain of

month-of-year can accept January, February,…December as values, a domain of dates can

accept all possible valid dates etc. We specify domain of attribute while creating a table.

An attribute cannot accept values that are outside of their domains. For example, In the above

table “STUDENT”, the Student_Id field has integer domain so that field cannot accept values

that are not integers for example, Student_Id cannot has values like, “First”, 10.11 etc.

5. Instance and Schema

Definition of schema: Design of a database is called the schema. Schema is of three

types: Physical schema, logical schema and view schema.

For example: In the following diagram, we have a schema that shows the relationship

between three tables: Course, Student and Section. The diagram only shows the design of the

database, it doesn’t show the data present in those tables. Schema is only a structural

view(design) of a database as shown in the diagram below.

The design of a database at physical level is called physical schema, how the data

stored in blocks of storage is described at this level.

Design of database at logical level is called logical schema, programmers and

database administrators work at this level, at this level data can be described as certain types

of data records gets stored in data structures, however the internal details such as

implementation of data structure is hidden at this level (available at physical level).

Design of database at view level is called view schema. This generally describes end user

interaction with database systems.

Definition of instance:

The data stored in database at a particular moment of time is called instance of

database. Database schema defines the variable declarations in tables that belong to a

particular database; the value of these variables at a moment of time is called the

instance of that database.

6. Keys

Key plays an important role in relational database; it is used for identifying unique

rows from table. It also establishes relationship among tables.

Primary Key – A primary is a column or set of columns in a table that uniquely identifies

tuples (rows) in that table.

Super Key – A super key is a set of one of more columns (attributes) to uniquely identify

rows in a table.

Candidate Key – A super key with no redundant attribute is known as candidate key

Alternate Key – Out of all candidate keys, only one gets selected as primary key, remaining

keys are known as alternate or secondary keys.

Composite Key – A key that consists of more than one attribute to uniquely identify rows

(also known as records & tuples) in a table is called composite key.

Foreign Key – Foreign keys are the columns of a table that points to the primary key of

another table. They act as a cross-reference between tables.

NULL Values

The NULL value of the table specifies that the field has been left blank during record

creation. It is totally different from the value filled with zero or a field that contains space.

Data Integrity

There are the following categories of data integrity exist with each RDBMS:

Entity integrity: It specifies that there should be no duplicate rows in a table.

Domain integrity: It enforces valid entries for a given column by restricting the type, the

format, or the range of values.

Referential integrity: It specifies that rows cannot be deleted, which are used by other

records.

User-defined integrity: It enforces some specific business rules that are defined by users.

These rules are different from entity, domain or referential integrity.

3. Difference between DBMS and RDBMS

Although DBMS and RDBMS both are used to store information in physical database but

there are some remarkable differences between them.

The main differences between DBMS and RDBMS are given below:

No. DBMS RDBMS

1) DBMS applications store data as file. RDBMS applications store data in a

tabular form.

2) In DBMS, data is generally stored in either a

hierarchical form or a navigational form.

In RDBMS, the tables have an identifier

called primary key and the data values

are stored in the form of tables.

3) Normalization is not present in DBMS. Normalization is present in RDBMS.

4) DBMS does not apply any security with

regards to data manipulation.

RDBMS defines the integrity

constraint for the purpose of ACID

(Atomocity, Consistency, Isolation and

Durability) property.

5) DBMS uses file system to store data, so there

will be no relation between the tables.

in RDBMS, data values are stored in the

form of tables, so a relationship between

these data values will be stored in the

form of a table as well.

6) DBMS has to provide some uniform methods

to access the stored information.

RDBMS system supports a tabular

structure of the data and a relationship

between them to access the stored

information.

7) DBMS does not support distributed

database.

RDBMS supports distributed

database.

8) DBMS is meant to be for small organization

and deal with small data. it supports single

user.

RDBMS is designed to handle large

amount of data. it supports multiple

users.

9) Examples of DBMS are file systems, xml etc. Example of RDBMS

are mysql, postgre, sql

server, oracle etc.

4. Normalization

o Normalization is the process of organizing the data in the database.

o Normalization is used to minimize the redundancy from a relation or set of relations.

It is also used to eliminate the undesirable characteristics like Insertion, Update and

Deletion Anomalies.

o Normalization divides the larger table into the smaller table and links them using

relationship.

o The normal form is used to reduce redundancy from the database table.

Types of Normal Forms

There are the four types of normal forms:

Normal

Form

Description

1NF A relation is in 1NF if it contains an atomic value.

2NF A relation will be in 2NF if it is in 1NF and all non-key attributes are fully

functional dependent on the primary key.

3NF A relation will be in 3NF if it is in 2NF and no transition dependency exists.

4NF A relation will be in 4NF if it is in Boyce Codd normal form and has no multi-

valued dependency.

5NF A relation is in 5NF if it is in 4NF and not contains any join dependency and

joining should be lossless.

First Normal Form (1NF)

o A relation will be 1NF if it contains an atomic value.

o It states that an attribute of a table cannot hold multiple values. It must hold only

single-valued attribute.

o First normal form disallows the multi-valued attribute, composite attribute, and their

combinations.

Example: Relation EMPLOYEE is not in 1NF because of multi-valued attribute

EMP_PHONE.

EMPLOYEE table:

EMP_ID EMP_NAME EMP_PHONE EMP_STATE

14 John 7272826385,

9064738238

UP

20 Harry 8574783832 Bihar

12 Sam 7390372389,

8589830302

Punjab

The decomposition of the EMPLOYEE table into 1NF has been shown below:

EMP_ID EMP_NAME EMP_PHONE EMP_STATE

14 John 7272826385 UP

14 John 9064738238 UP

20 Harry 8574783832 Bihar

12 Sam 7390372389 Punjab

12 Sam 8589830302 Punjab

Second Normal Form (2NF)

o In the 2NF, relational must be in 1NF.

o In the second normal form, all non-key attributes are fully functional dependent on the

primary key

Example: Let's assume, a school can store the data of teachers and the subjects they teach. In

a school, a teacher can teach more than one subject.

TEACHER table

TEACHER_ID SUBJECT TEACHER_AGE

25 Chemistry 30

25 Biology 30

47 English 35

83 Math 38

83 Computer 38

In the given table, non-prime attribute TEACHER_AGE is dependent on TEACHER_ID

which is a proper subset of a candidate key. That's why it violates the rule for 2NF.

To convert the given table into 2NF, we decompose it into two tables:

TEACHER_DETAIL table:

TEACHER_ID TEACHER_AGE

25 30

47 35

83 38

TEACHER_SUBJECT table:

TEACHER_ID SUBJECT

25 Chemistry

25 Biology

47 English

83 Math

83 Computer

Third Normal Form (3NF)

o A relation will be in 3NF if it is in 2NF and not contain any transitive partial

dependency.

o 3NF is used to reduce the data duplication. It is also used to achieve the data integrity.

o If there is no transitive dependency for non-prime attributes, then the relation must be

in third normal form.

A relation is in third normal form if it holds atleast one of the following conditions for every

non-trivial function dependency X → Y.

1. X is a super key.

2. Y is a prime attribute, i.e., each element of Y is part of some candidate key.

EMPLOYEE_DETAIL table:

EMP_I

D

EMP_NAME EMP_ZIP EMP_STAT EMP_CITY

222 Harry 201010 UP Noida

333 Stephan 02228 US Boston

444 Lan 60007 US Chicago

555 Katharine 06389 UK Norwich

666 John 462007 MP Bhopal

Super key in the table above:

1. {EMP_ID}, {EMP_ID, EMP_NAME}, {EMP_ID, EMP_NAME, EMP_ZIP}....so on

Candidate key: {EMP_ID}

Non-prime attributes: In the given table, all attributes except EMP_ID are non-

prime.

Here, EMP_STATE & EMP_CITY dependent on EMP_ZIP and EMP_ZIP dependent

on EMP_ID. The non-prime attributes (EMP_STATE, EMP_CITY) transitively

dependent on super key(EMP_ID). It violates the rule of third normal form.

That's why we need to move the EMP_CITY and EMP_STATE to the new

<EMPLOYEE_ZIP> table, with EMP_ZIP as a Primary key.

EMPLOYEE table:

EMP_ID EMP_NAME EMP_ZIP

222 Harry 201010

333 Stephan 02228

444 Lan 60007

555 Katharine 06389

666 John 462007

EMPLOYEE_ZIP table:

EMP_ZIP EMP_STATE EMP_CITY

201010 UP Noida

02228 US Boston

60007 US Chicago

06389 UK Norwich

462007 MP Bhopal

Boyce Codd normal form (BCNF)

o BCNF is the advance version of 3NF. It is stricter than 3NF.

o A table is in BCNF if every functional dependency X → Y, X is the super key of the

table.

o For BCNF, the table should be in 3NF, and for every FD, LHS is super key.

Example: Let's assume there is a company where employees work in more than one

department.

EMPLOYEE table:

EMP_ID EMP_COUNTRY EMP_DEPT DEPT_TYPE EMP_DEPT_NO

264 India Designing D394 283

264 India Testing D394 300

364 UK Stores D283 232

364 UK Developing D283 549

In the above table Functional dependencies are as follows:

1. EMP_ID  →  EMP_COUNTRY

2. EMP_DEPT  →   {DEPT_TYPE, EMP_DEPT_NO}

Candidate key: {EMP-ID, EMP-DEPT}

The table is not in BCNF because neither EMP_DEPT nor EMP_ID alone are keys.

To convert the given table into BCNF, we decompose it into three tables:

EMP_COUNTRY table:

EMP_ID EMP_COUNTRY

264 India

264 India

EMP_DEPT table:

EMP_DEPT DEPT_TYPE EMP_DEPT_NO

Designing D394 283

Testing D394 300

Stores D283 232

Developing D283 549

EMP_DEPT_MAPPING table:

EMP_ID EMP_DEPT

D394 283

D394 300

D283 232

D283 549

Functional dependencies:

1. EMP_ID   →    EMP_COUNTRY

2. EMP_DEPT   →   {DEPT_TYPE, EMP_DEPT_NO}

Candidate keys:

For the first table: EMP_ID

For the second table: EMP_DEPT

For the third table: {EMP_ID, EMP_DEPT}

Now, this is in BCNF because left side part of both the functional dependencies is a key.

Fourth normal form (4NF)

o A relation will be in 4NF if it is in Boyce Codd normal form and has no multi-valued

dependency.

o For a dependency A → B, if for a single value of A, multiple values of B exists, then

the relation will be a multi-valued dependency.

Example

STUDENT

STU_ID COURSE HOBBY

21 Computer Dancing

21 Math Singing

34 Chemistry Dancing

74 Biology Cricket

59 Physics Hockey

The given STUDENT table is in 3NF, but the COURSE and HOBBY are two independent

entity. Hence, there is no relationship between COURSE and HOBBY.

In the STUDENT relation, a student with STU_ID, 21 contains two

courses, Computer and Math and two hobbies, Dancing and Singing. So there is a Multi-

valued dependency on STU_ID, which leads to unnecessary repetition of data.

So to make the above table into 4NF, we can decompose it into two tables:

STUDENT_COURSE

STU_ID COURSE

21 Computer

21 Math

34 Chemistry

74 Biology

59 Physics

STUDENT_HOBBY

STU_ID HOBBY

21 Dancing

21 Singing

34 Dancing

74 Cricket

59 Hockey

next → ← prev

Fifth normal form (5NF)

o A relation is in 5NF if it is in 4NF and not contains any join dependency and joining should be lossless.

o 5NF is satisfied when all the tables are broken into as many tables as possible in order to avoid redundancy.

o 5NF is also known as Project-join normal form (PJ/NF).

Example

SUBJECT LECTURER SEMESTER

Computer Anshika Semester 1

Computer John Semester 1

Math John Semester 1

Math Akash Semester 2

Chemistry Praveen Semester 1

In the above table, John takes both Computer and Math class for Semester 1 but he doesn't take Math class for Semester 2. In this case,

combination of all these fields required to identify a valid data.

Suppose we add a new Semester as Semester 3 but do not know about the subject and who will be taking that subject so we leave

Lecturer and Subject as NULL. But all three columns together acts as a primary key, so we can't leave other two columns blank.

So to make the above table into 5NF, we can decompose it into three relations P1, P2 & P3:

P1

SEMESTER SUBJECT

Semester 1 Computer

Semester 1 Math

Semester 1 Chemistry

Semester 2 Math

P2

SUBJECT LECTURER

Computer Anshika

Computer John

Math John

Math Akash

Chemistry Praveen

P3

SEMSTER LECTURER

Semester 1 Anshika

Semester 1 John

Semester 1 John

Semester 2 Akash

Semester 1 Praveen

3. ORACLE TERMINOLOGY

Terminology

The following table defines the key terms used in the context of Oracle Cloud Infrastructure

Storage Software Appliance– Cloud Distribution.

Term Description

Block storage Block storage is an abstraction that is used by storage volumes and most

storage devices such as hard disks, flash drives, and tape. A block is

typically a range of contiguous bytes, and a volume is a range of contiguous

blocks. Storage protocols such as SCSI, iSCSI, and Fibre Channel provide a

method for accessing block storage devices that are attached either locally

or remotely. File systems, some databases, and other storage applications

use block I/O to access storage volumes to optimize performance and data

granularity.

Block storage optimizes storage for IOPS and block-based access and

provides POSIX-compliant file systems for Oracle Cloud Infrastructure

Compute Classic instances. It is limited in terms of scalability and does not

support the definition of granular metadata for stored data.

Container A container is a user-created resource in Oracle Cloud Infrastructure Object

Storage Classic. It can hold an unlimited number of objects, unless you

specify a quota for the container. Note that containers cannot be nested.

FileSystem (or

filesystem)

A FileSystem in Oracle Cloud Infrastructure Storage Software Appliance

connects a directory on the Oracle Cloud Infrastructure Compute Classic

instance that hosts the appliance to a container on the storage service.

Term Description

Generally, file system (two words) means the mechanism that operating

systems use to manage files on disks. This general meaning is distinct from

the meaning of filesystem (one word) in the context of Oracle Cloud

Infrastructure Storage Software Appliance– Cloud Distribution.

NFS v4 NFS v4 is version 4 of NFS (network file system), a distributed file system

protocol defined in RFC 3530 (https://www.ietf.org/rfc/rfc3530.txt). It

enables client computers to mount file systems that exist on remote servers

and access those remote file systems over the network as though they were

local file systems.

Object storage Object storage provides an optimal blend of performance, scalability, and

manageability when storing large amounts of unstructured data. Multiple

storage nodes form a single, shared, horizontally scalable pool in which

data is stored as objects (blobs of data) in a flat hierarchy of containers.

Each object stores data, the associated metadata, and a unique ID. You can

assign custom metadata to containers and objects, making it easier to find,

analyze, and manage data.

Applications use the unique object IDs to access data directly via REST

API calls. Object storage is simple to use, performs well, and scales to a

virtually unlimited capacity.

Oracle Cloud

Infrastructure

Compute

Classic

Oracle Cloud Infrastructure Compute Classic is a secure, reliable, low cost,

standards-based infrastructure service that you can use to rapidly provision

virtual machines on Oracle Cloud with all the necessary storage and

networking resources, manage and scale your virtual machine topology in

the cloud easily, and migrate your Oracle and third-party applications to

Oracle Cloud.

See Also: Oracle Cloud Infrastructure Compute Classic Terminology in

Using Oracle Cloud Infrastructure Compute Classic.

Oracle Cloud

Infrastructure

Object Storage

Oracle Cloud Infrastructure Object Storage Classic provides a low cost,

reliable, secure, and scalable object-storage solution for storing unstructured

data and accessing it anytime from anywhere. It is ideal for data backup,

Term Description

Classic archival, file sharing, and storing large amounts of unstructured data like

logs, sensor-generated data, and VM images.

4. DATABASE CONNECTION

To create a database connection:

1. In the Connections navigator in SQL Developer, right-click the Connections node and

select New Connection.

The New / Select Database Connection dialog box appears, with the Oracle tab

displayed.

2. Enter the following information:

In the Connection Name field, enter the name to use for this database

connection.

In the Username field, enter the name of the user for whom this database

connection is being created.

In the Password field, enter the password for the user.

In the Connection Type field, select the database connection type.

The connection types are:

Basic

TNS

LDAP

Advanced

Local/Bequeath

When you choose a connection type, the fields below will change to be

appropriate for the selected connection type. This example describes the fields

for the Basic connection type.

In the Role field, select Default or SYSDBA, based on the role assigned to the

user.

In the Hostname field, enter the name of the host where the database is

located.

In the Port field, enter the port for the database.

In the SID field, enter the SID for the database (when the database connection

is for a non-CDB user or for a multitenant container database (CDB) user):

To create a database connection:

1. In the Connections navigator in SQL Developer, right-click the Connections node and

select New Connection.

The New / Select Database Connection dialog box appears, with the Oracle tab

displayed.

2. Enter the following information:

In the Connection Name field, enter the name to use for this database

connection.

In the Username field, enter the name of the user for whom this database

connection is being created.

In the Password field, enter the password for the user.

In the Connection Type field, select the database connection type.

The connection types are:

Basic

TNS

LDAP

Advanced

Local/Bequeath

When you choose a connection type, the fields below will change to be

appropriate for the selected connection type. This example describes the fields

for the Basic connection type.

In the Role field, select Default or SYSDBA, based on the role assigned to the

user.

In the Hostname field, enter the name of the host where the database is

located.

In the Port field, enter the port for the database.

In the SID field, enter the SID for the database (when the database connection

is for a non-CDB user or for a multitenant container database (CDB) user)

When a database connection to a non-CDB or CDB is created for an administrative user

such as SYS, SYSDBA is typically specified in the Role field for the connection.

In the Service name field, enter the service name for the pluggable database (PDB),

including the domain name (when the database connection is for a PDB user):

When a database connection to a PDB is created for an administrative user such as

SYS, SYSDBA is typically specified in the Role field for the connection.

3. Optionally, click Test to test that the data you provided will allow the specified user to

connect to the database.

4. When you are finished, click Connect to connect using the database connection, or

click Save to save the database creation.

5. CREATING TABLES:

The CREATE TABLE statement is used to create a new table in a database.

Syntax

CREATE TABLE table_name (

    column1 datatype,

    column2 datatype,

    column3 datatype,

 );

The column parameters specify the names of the columns of the table.

The datatype parameter specifies the type of data the column can hold (e.g. varchar, integer,

date, etc.).

SQL CREATE TABLE Example

The following example creates a table called "Persons" that contains five columns: PersonID,

LastName, FirstName, Address, and City:

Example

CREATE TABLE Persons (

    PersonID int,

    LastName varchar(255),

    FirstName varchar(255),

    Address varchar(255),

    City varchar(255)

);

The PersonID column is of type int and will hold an integer.

The LastName, FirstName, Address, and City columns are of type varchar and will hold

characters, and the maximum length for these fields is 255 characters.

The empty "Persons" table will now look like this:

PersonID LastName FirstName Address City

Create Table Using Another Table

A copy of an existing table can also be created using CREATE TABLE.

The new table gets the same column definitions. All columns or specific columns can

be selected.

If you create a new table using an existing table, the new table will be filled with the

existing values from the old table.

Syntax

CREATE TABLE new_table_name AS

    SELECT column1, column2,...

    FROM existing_table_name

    WHERE ....;

The following SQL creates a new table called "TestTables" (which is a copy of the

"Customers" table):

Example

CREATE TABLE TestTable AS

SELECT customername, contactname

FROM customers;

6. The Basics of SQL

SQL

o SQL stands for Structured Query Language. It is used for storing and managing data

in relational database management system (RDMS).

o It is a standard language for Relational Database System. It enables a user to create,

read, update and delete relational databases and tables.

o All the RDBMS like MySQL, Informix, Oracle, MS Access and SQL Server use SQL

as their standard database language.

o SQL allows users to query the database in a number of ways, using English-like

statements.

Rules:

SQL follows the following rules:

o Structure query language is not case sensitive. Generally, keywords of SQL are

written in uppercase.

o Statements of SQL are dependent on text lines. We can use a single SQL statement on

one or multiple text line.

o Using the SQL statements, you can perform most of the actions in a database.

o SQL depends on tuple relational calculus and relational algebra.

SQL process:

o When an SQL command is executing for any RDBMS, then the system figure out the

best way to carry out the request and the SQL engine determines that how to interpret

the task.

o In the process, various components are included. These components can be

optimization Engine, Query engine, Query dispatcher, classic, etc.

o All the non-SQL queries are handled by the classic query engine, but SQL query

engine won't handle logical files.

7. SQL Grammar

SQL Statement Syntax

AND / OR SELECT column_name(s)

FROM table_name

WHERE condition

AND|OR condition

ALTER TABLE ALTER TABLE table_name

ADD column_name datatype

or

ALTER TABLE table_name

DROP COLUMN column_name

AS (alias) SELECT column_name AS column_alias

FROM table_name

or

SELECT column_name

FROM table_name  AS table_alias

BETWEEN SELECT column_name(s)

FROM table_name

WHERE column_name

BETWEEN value1 AND value2

CREATE DATABASE CREATE DATABASE database_name

CREATE TABLE CREATE TABLE table_name

(

column_name1 data_type,

column_name2 data_type,

column_name3 data_type,

...

)

CREATE INDEX CREATE INDEX index_name

ON table_name (column_name)

or

CREATE UNIQUE INDEX index_name

ON table_name (column_name)

CREATE VIEW CREATE VIEW view_name AS

SELECT column_name(s)

FROM table_name

WHERE condition

DELETE DELETE FROM table_name

WHERE some_column=some_value

or

DELETE FROM table_name

(Note: Deletes the entire table!!)

DELETE * FROM table_name

(Note: Deletes the entire table!!)

DROP DATABASE DROP DATABASE database_name

DROP INDEX DROP INDEX table_name.index_name (SQL Server)

DROP INDEX index_name ON table_name (MS Access)

DROP INDEX index_name (DB2/Oracle)

ALTER TABLE table_name

DROP INDEX index_name (MySQL)

DROP TABLE DROP TABLE table_name

EXISTS IF EXISTS (SELECT * FROM table_name WHERE id = ?)

BEGIN

--do what needs to be done if exists

END

ELSE

BEGIN

--do what needs to be done if not

END

GROUP BY SELECT column_name, aggregate_function(column_name)

FROM table_name

WHERE column_name operator value

GROUP BY column_name

HAVING SELECT column_name, aggregate_function(column_name)

FROM table_name

WHERE column_name operator value

GROUP BY column_name

HAVING aggregate_function(column_name) operator value

IN SELECT column_name(s)

FROM table_name

WHERE column_name

IN (value1,value2,..)

INSERT INTO INSERT INTO table_name

VALUES (value1, value2, value3,....)

or

INSERT INTO table_name

(column1, column2, column3,...)

VALUES (value1, value2, value3,....)

INNER JOIN SELECT column_name(s)

FROM table_name1

INNER JOIN table_name2

ON table_name1.column_name=table_name2.column_name

LEFT JOIN SELECT column_name(s)

FROM table_name1

LEFT JOIN table_name2

ON table_name1.column_name=table_name2.column_name

RIGHT JOIN SELECT column_name(s)

FROM table_name1

RIGHT JOIN table_name2

ON table_name1.column_name=table_name2.column_name

FULL JOIN SELECT column_name(s)

FROM table_name1

FULL JOIN table_name2

ON table_name1.column_name=table_name2.column_name

LIKE SELECT column_name(s)

FROM table_name

WHERE column_name LIKE pattern

ORDER BY SELECT column_name(s)

FROM table_name

ORDER BY column_name [ASC|DESC]

SELECT SELECT column_name(s)

FROM table_name

SELECT * SELECT *

FROM table_name

SELECT DISTINCT SELECT DISTINCT column_name(s)

FROM table_name

SELECT INTO SELECT *

INTO new_table_name [IN externaldatabase]

FROM old_table_name

or

SELECT column_name(s)

INTO new_table_name [IN externaldatabase]

FROM old_table_name

SELECT TOP SELECT TOP number|percent column_name(s)

FROM table_name

TRUNCATE TABLE TRUNCATE TABLE table_name

UNION SELECT column_name(s) FROM table_name1

UNION

SELECT column_name(s) FROM table_name2

UNION ALL SELECT column_name(s) FROM table_name1

UNION ALL

SELECT column_name(s) FROM table_name2

UPDATE UPDATE table_name

SET column1=value, column2=value,...

WHERE some_column=some_value

WHERE SELECT column_name(s)

FROM table_name

WHERE column_name operator value