Data Definition Language/ Data Description Language (DDL)

.

Introduction of DDL :

It is a language that allows the users to define data and their relationship to other types of data.
DDL is the short form of Data Definition Language, which deals with database schema and description of how the data should reside in the database.
It is mainly used to create files, database, data dictionary and table within database.
DDL can be used to define the conceptual/ Global/ Logical schema.
A DDL is a language used to define data structures and modify data.

Following are the commands of DDL :

CREATE :

It is used to create object in the database. The CREATE command can be used to establish each of these database on your platform.

ALTER :

It alters the structure of the database. The ALTER command allows you to make changes to the structure of a table without deleting and recreating it.

Drop :

Delete object from the database. The final command of the Data Definition Language, DROP, allows us to remove entire database objects from our DBMS.

For example

DROP TABLE personal_info

DROP DATABASE employees

TRUNCATE :

Remove all records from a table, including all space allocated for the record are removed.

COMMENT :

Add comment to the data dictionary.

RENAME :

Rename an object.

Comments

Important questions of C programming (BCA)

. What is the characteristics of a good program? Explain types of language processor. Explain any two system design tools. Explain Program Development Life Cycle. Define programing techniques. Different between top-down and button - up approach with suitable example. Difference between cohesion and coupling. Define identifiers, constants, variables and keywords. Explain datatypes. Explain different types of datatypes available in C. Define operator. Explain its types with suitable example. Explain decision making statement. Explain its type with example. Difference between while, do while loop, for loop. Write a program to find the fibonacci sequence. What is jumping statement. Explain its types with suitable example. Write a program to display following: * ** *** ...

BCA Math II old question model solution

. BCA Math II question model 2018: BCA Math II question model 2019: BCA Math II question model 2020:

8085 Microprocessor and its Operation

. The 8085 microprocessor is an 8 bit microprocessor designed by Intel and introduced in 1976. It is a widely used microprocessor in embedded systems and educational settings due to its simplicity and effectiveness. Here's an overview of its architecture and operation: Data Bus: 8-bit: It can handle 8 bits of data at a time, which means it processes 1 byte of data in a single operation. Address Bus: 16-bit: It can address up to 2 16 2 16 = 65,536 memory locations, which translates to 64KB of addressable memory. Registers: General Purpose Registers: 6 registers (B, C, D, E, H, L) which can be used individually or in pairs (BC, DE, HL) for 16-bit operations. Accumulator: An 8-bit register (A) used for arithmetic and logic operations. Flag Register: Contains flags that indicate the status of the processor (Zero, Carry, Sign, Parity, and Auxiliary Carry Flags). Program Counter (PC): 16-bit register that holds the address of the next instruction to be exec...

Computer Engineering

Search This Blog