Database Concepts
Assignment on Database Concepts
Q1. What is a Database?
Ans: A Database is an organized collection of data pertaining to an organization/Entity.
Q2. Expand DBMS? Give example of two DBMS software.
Ans: DBMS stands for Database Management System. Two popular DBMS software are OpenOffice.org Base, MySQL, MS Access.
Q3. Explain the role of DBMS software.
Ans. A database management system is a software package with computer programs that controls the creation, maintenance, and use of a database. It allows organizations to conveniently develop databases for various applications.
Q4. What is Database Server?
Ans: Database servers are dedicated computers that hold the actual databases and run only the DBMS and related software. Database servers are referred to as Back-ends.
Q5. What is Client Server Model?
Ans: When information is fetched by some computers from remote machine or servers, Computer who make request for information is known as client and those who fulfill the request made by client are known as server. This kind of model is known as Client Server Model.
Q6. What is RDBMS?
Ans; RDBMS stands for Relational Database Management System. It is a Database Management system that is based on the relational model as introduced by E.F Codd in 1969.
Q7. A………………… can have one or more tables.
Q8. What is key Field or Primary Key?
Ans. Every table in a database has a key field which ensures that there are 100% unique values throughout the database. Every database table should have one or more fields designated as key. You can assign a unique value to this key for differentiating records that may have similar names or
address. For example:
RollNo Name Standard Section
1 Ram X A
2 Ravi X A
3 Ravi X A
4 Sanjay X B
Here RollNo is assigned as Key Field or Primary Key.
Q8. What is a Table?
Ans: A Table is a set of data elements that is organised using a model of vertical columns and horizontal rows.
Q9. A table has a defined no. of ……………………………….. and can have any no. of ……………………….
Q10. Define Column and Row.
Ans. Column: A Column is a set of data values of a particular data type. Column is also known as attribute.
Row: A row also called a record or tuple represents a single, data item in a table.
Q11. What are Datatypes? Explain various data types used in RDBMS.
Ans: Datatypes are used to identify which type of data (value) we are going to store in the database. Fields themselves can be of different types depending on the data they contain. Data types in OpenOffice base is broadly classified into five categories listed below.
Numeric Types
Alphanumeric Types
Binary Types
Date time
Other Variable types
Q12. What is Primary Key?
Ans: Unique field is called the primary key (PK). A primary key is a unique value that identifies a row in a table. For example, ClientID is the primary key in the Client table.
Q13. What is Foreign Key?
Ans: The referred field ClientID which occurs in the Sales table is called the foreign key (FK). Hence, the foreign key identifies a column or set of columns in one (referencing) table that refers to a column or set of columns in another (referenced) table.
The “one” side of a relation is always the parent, and provides the PK attributes to be copied. The “many” side of a relation is always the child, into which the FK attributes are copied. Memorize it:
one, parent, PK; many, child, FK.
Q14. Write the usage of Database Management System.
Ans: 1. Database management system is used to ensure sharing of data.
2. DBMS ensure security of data.
3. DBMS is used to manage bulk amount of data.
Q15. What do you mean by SQL?
Ans. SQL stands for Structured Query Language. This language is used by DBMS/RDBMS software to prompt queries in standard format.
Q16. Give classification of SQL?
Ans: SQL can be categorized into two categories:
DDL: Data Definition Language- Data definition language is used to define structure where data is arranged.
DML: Data Manipulation Language-Data Manipulation Language is used to manipulate data existing in database.
Q17: Recognize following SQL command type:
Insert, Select,Delete, Create Table, Create View, Alter Table, Drop Table
Ans:
DDL: Create Table, Create View, Alter Table, Drop Table
DML: Insert, Select, Delete