SEBA Class 9 Computer Science Chapter 6: Database Part I All Questions & Answers
Database Part I
1. Multiple Choice Questions
1) DBMS is a
a) Type of a database b) Set of computer program c) key d) field
Ans: a) Type of a database
2) Which of the following key is compound of additional fields?
a) Primary b) Foreign c) Super d) Alternate
Ans: a) Primary
3) Which option is used to change the appearance and size of various controls of a Form?
a) Design View b) Form View c) Layout view d) None of these
Ans: c) Layout view
4) Which key defines a relationship between two tables
a) Primary key b) Candidate key c) Secondary key d) None of these
Ans: a) Primary key
5) Which icon indicates the edit mode in Access?
a) Clip b) Pen c) Pencil d) None of these
Ans: c) Pencil
2. Fill in the blanks:-
1) In Relational databases data are stored in multiple tables to remove redundancy.
2) A candidate key is called composite key.
3) Microsoft Access is a relational database.
4) Datasheet view displays the table as grid.
5) Form allows you to add and update data in a table, one record at a time.
3. Answer the following questions:-
1) What is Database? Give examples.
Ans :- The Database is a collection of information or data which is arranged in a proper order and it is stored electronically in the computer system. For ex:- Telephone directory (which stores data like name, phone numbers and other contact details etc)
2) What is the need for database?
Ans :- Storing the data and maintaining it in many papered registers like an attendance
register in a school, which results in creation of problems like it needs a large place to keep such registers, it takes too much time to find the records etc. Storing of data electronically will be much beneficial in reducing such type of problems.
Electronically storing of data means the data or information is saved in a file/database in the computer. The data stored electronically in database is a lot in amount, orderly arranged and duplication of data is avoided. The data only can accessed/retrieved only by the authorized/registered users, which helps to maintain the data privacy. The tasks inrelation to searching of data, updating/editing an existing data, or old data deleting is done very easily and quickly.
3) Define : Primary key, Foreign key, Candidate key, Super key ?
Ans :- The following terms are described as :-
- i) Primary Key:- One field or group of fields designed in database, together form as Primary Key. The property of a primary key is that not more than one record is allowed with the same value for the field. Without filling in the value of a primary key field, its impossible to add a record in a table.
- ii) Foreign key :- It is a key, which is used to keep the link/relation between two tables. It is nothing but a field or collection of field in one table that refers to the primary key in the another table.
- iii) Candidate key :- A field or group of fields that can be used as the primary key of the table is called candidate key. In the database, primary key can be out of the defined candidate N keys The other remaining candidate keys N-1 are called alternate keys. If incase the candidate key is composed with more than one field, then it (candidate key) is called as composite key.
- iv) Super key :- in a database it is a set of fields which uniquely identifies the record in a table. Super key is also a set of field, which is not required for identifying a record in a table. It is the combination of field with ID field forms the. For ex:- together form a super key which also can identify a record uniquely
4) Differentiate between Flat file databases and Relational database
Ans :- The difference between Flat file databases and Relational database is a s followed:-
- i) Flat file databases :- When the data is stored in the form of a plain text file and it cannot be added in multiple tables.
- ii) Relational database :- The data items are related to each other when the data is been stored. It handles multiple tables which stores/ arranges the text in rows and columns.
5) What are data types? List the various types of data types used in Access 2007 and explain any four of them.
Ans :- what kind/type of data is to be stored is been determined by Data type. MS Access provides different types of data types, which are used for different purposes. The value that is to stored in the given field is been determined by datatypes. Each field can store data consisting of only a single data type. The different types of data types are as follows:-
- i) Auto Number :- When new record is been created then unique values of such is created by Auto number. This field can be primarily used as the Primary Key in Access.
- ii) Number :– The Number field can store numeric values ranging upto 16 bytes of data.
- iii) Date/Time :- The Date/Time field allows storage of date and time information.
- iv) Text :- A text field can contain value that that are in text, numeric, or combination of both. A text field can contain upto 255 characters.
6) What is a query? Explain the parts of a query window.
Ans:- Query is a simple question that you ask to find some specific information from a
database or on the basis of the search conditions query allows the user access information from one or more tables. Queries can be made on tables and the results are being displayed in the form of table i.e is in the format of rows and columns with the set of records that matches the given condition. There are two major parts of the query window which are :
- i) Design area :- It is also known as top portion which shows tables, fields, or subqueries that you may want to use in query.
- ii) Grid portion :- It is also known as lower portion. It contains the columns in which the user can set up the fields.
7) What do you understand by criteria?
Ans :- It is the property which contains the condition on which the records are been filtered in the Query output.
