# NCERT Solutions for Class 11 Accountancy Financial Accounting Part-2 Chapter 7

## Structuring Database for Accounting Class 11

### Short answers : Solutions of Questions on Page Number : 549

Q1 :

State main categories of data models.

The following are the various categories of data models.

(i)  Relational Data Model

(ii) Hierarchical Data Model

(iii) Network Data Model

1. Relational Data Model- This data model is based on the relationship of collected data values. In this data model, data is organised into rows and columns. A row is regarded as a tuple, a column header is known as an attribute and the collective set of rows and columns, i.e. a table is called a relation. The table is known as a relation as it expresses the relationship between the rows and columns. This model provides the storage and retrieval functions and defines the data structure.

The relational data model was first introduced by Ted Codd in 1970 in a classic paper Codd, 1970. Prior to this, there were other data models which were proposed in sixties such as, hierarchical data model and network data model. These models are also known as legacy-models due to their large existing user-base.

2. Hierarchical Data Model- This data model mainly consists of records and parent-child relationships. While, a record is regarded as a collection of values that provides information regarding an entity or a relationship instance, on the other hand, a parent-child relationship explains the relationship between the parent record and children record type. In this data model, the records are organised in a tree structure rather than as an arbitrary graph. The data is represented by a collection of records and relationship among data is represented by links.

3. Network Data Model- This type of data model is sometimes also known as DBTG model, as the original network model was presented in CODASYL Data Base Task Group's 1971, i.e. (DBTG). This data model basically consists of records and sets. While, data is stored in records, which consists of a group of related data values, on the other hand, sets describes the relationship between two records types. In this data model, data is also represented by collection of records and the relationship among data is represented by sets. This model provides many-to-many relationships in data.

Q2 :

How are computers useful in processing the accounting data?

Data processing is a process of collecting, storing, summarising, analysing and interpreting the data and facts so as to represent reliable information for efficient and effective decision making. Data processing, in short, is a transformation of raw data into useful information. Computer system plays a very important role in processing the accounting data. Data processing requires a mechanism to store data content in a manner that allows easy and convenient retrieval of data as and when required. This can be easily done with the help of computers by designing suitable database for accounting. Moreover, computers also help in eliminating the duplication of data. Unlike the manual accounting system, computers are not subject to tiredness, boredom or fatigue, therefore; the reliability of data processed by computers is very high. Besides reliability, computers can process data at comparatively higher speed and with great degree of precision and accuracy.

Q3 :

What do you understand by accounting data? Discuss the stages through which it is finally transformed for being presented as information in financial statements.

Q4 :

What do you understand by database? How does it differ from DBMS?

Q5 :

What is meant by entity type? How it is different from entity set? Illustrate by giving suitable example from accounting reality.

Q6 :

What do you understand by relationship type? How is it different from relationship instance and relationship set?

Q7 :

What do you understand by multi-valued attribute? How is it different from complex and composite attribute? Illustrate by giving suitable example.

Q8 :

What do you understand by the concept of weak entity used in data modelling? Explain the relevance of owner entity type, partial key and identifying relationship in the context of such modelling.

Q9 :

What is a participation role? State the circumstances under which the use of role names becomes necessary in description of relationship types.

Q10 :

Define foreign key. How is this concept useful in relational data model? Illustrate with suitable example.

Q11 :

What is meant by NULL value? What are the reasons that lead to their occurrence in database relations?

Q12 :

Why are duplicate tuples not allowed in a relation?

Q13 :

What do you understand by union compatibility of relations? For which operations such compatibility is required and why?

Q14 :

What is the need for database normalisation?

### Long answers : Solutions of Questions on Page Number : 549

Q1 :

Discuss the basic concepts of Entity Relationship (ER) Model. Illustrate as to how an ER model is diagrammed.

Q2 :

What integrity constraints are specified on database schema? Why each is considered important?

Q3 :

Discuss the different types of update operations in relation to the integrity constraints which must be satisfied in a relational database model.

Q4 :

Discuss the steps you would take to transform an ER Model into various relations of Relational Data Model. Give suitable examples.

Financial Accounting Part-2 - Accountancy : CBSE NCERT Exercise Solutions for Class 11th for Structuring Database for Accounting will be available online in PDF book form soon. The solutions are absolutely Free. Soon you will be able to download the solutions.

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