Cs3431 SQL: Updates (DML) and Views (DDL). cs3431 SQL DML (Updating the Data) Insert Delete Update.
Data Definition and Data Manipulation Language-DDL & DML
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Transcript of Data Definition and Data Manipulation Language-DDL & DML
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About Me
Md. Selim HossainLecturer
Dept. of CSEUTTARA UNIVERSITY
House#05, Section#06,Road#15, Uttara, Dhaka-1230.
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Database Management System (DBMS)Md. Selim Hossain
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Topics for Today
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Data Definition Language (DDL)
Data Manipulation Language (DML)
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SQL statements are divided into two major
categories:
Data Definition Language (DDL) and Data Manipulation Language (DML).
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Data Definition Language (DDL)
• DDL statements are used to build and modify the structure of tables and other objects in the database.
• DDL is a sub-language of SQL used to create and manipulate objects in a database. DDL provides the following statements to manipulate the object in database:
CREATE, ALTER, DROP, TRUNCATE, RENAME
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Data Definition Language (DDL) CREATE statement (to create objects in the database):• The CREATE statement in SQL creates a
component in a relational database management system (RDBMS).
• The CREATE command is used to establish a new database, table, index, or stored procedure.
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CREATE TABLE statement• A commonly used CREATE command is the
CREATE TABLE command. The typical usage is: CREATE TABLE [table name] ( [column
definitions] ) [table parameters]
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CREATE TABLE statement• An example of statement to create a table
named employees with a few columns is:
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CREATE TABLE statement
Note: The full structure of table can be viewed with the DESC command.
DESC <TABLE_NAME>
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DROP statement
• The DROP statement destroys an existing database, table, index, or view.
• A DROP statement in SQL removes a component from a relational database management system (RDBMS).
• Drop statement is used to delete an existing object from the database. It can also be used to delete any column from a table.
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DROP statement
• The DROP statement is distinct from the DELETE and TRUNCATE statements, in that DELETE and TRUNCATE do not remove the table itself. For example, a DELETE statement might delete some (or all) data from a table while leaving the table itself in the database, whereas a DROP statement removes the entire table from the database.
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DROP statement
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DROP statement The typical usage is simply:
• For example, the command to drop a table named employees is:
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ALTER statement
• The ALTER statement modifies an existing database object or, Alter statement is used to modify the structure of an existing object.
• Below alteration can be done on a table:o Addition of new columnso Deletion of existing columnso Changing the data type of columnso Changing the size of columns
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ALTER statement
• The typical usage is:
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ALTER statement
Note: To change the data type of a column, the column must be empty.
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RENAME statement
Rename statement is used to rename an existing object from a database
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RENAME statement
• The RENAME statement is used to rename a database table.
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TRUNCATE statement
• The TRUNCATE statement is used to delete all data from a table. It's much faster than DELETE.
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Data Manipulation Language (DML)
• A data manipulation language (DML) is a family of syntax elements similar to a computer programming language used for selecting, inserting, deleting and updating data in a database.
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Data Manipulation Language (DML) DML also known as query language
Two classes of languages Procedural – user specifies what data is
required and how to get those data Nonprocedural – user specifies what data is
required without specifying how to get those data
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Data Manipulation Language (DML)
• DML is a sub-language of SQL. It is used to manipulate the data stored in a table.
• DML provides the following statements for data manipulation:
INSERTUPDATEDELETE
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Data Manipulation Language (DML)
INSERT Statement• INSERT statement is used to insert a new
record into a table.
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Data Manipulation Language (DML)INSERT Statement
• Example• Consider a table 'EMP' having columns
named EMPNO, NAME, SAL and JOB. We can be used the below INSERT statement to insert a new record to it.
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UPDATE Statement
• Update statement is used to update an existing record in a table.
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UPDATE Statement• If the where clause of omitted, the statement
will update all the values in the particular column.
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UPDATE Statement
• Note: IS NULL is used for assignment and =NULL is used to recognize.
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DELETE Statement
• Delete Statement is used to delete records from a table.
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DELETE Statement
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DELETE Statement
• Below statement will delete all records from the table.
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