BIKESH SUNAR

The role of database Administrator is:

1. Defining the internal schema: The DBA must define how the data is to be represented in the stored database. This process is usually referred to as physical database design.

2.Defining the external Schema: The DBA must also decide exactly what information is to be stored inthe database. This process is usually called as a logical (sometimes conceptual) database design.

3. Liaising with users: It is the business of the DBA to liaise with user to ensure...

Prototyping is a process of quickly putting together a working model in order to test various aspects of a design illustrate ideas or features and gather early user feedback.

A domain is the set of possible values for a given attribute, and it can be considered as a constrait on the value of the attribute, such as value of an attribute marks of a subject must be integer value like 56 and it should be withwin the range of 0 to full marks.

A tuple is a complete row of the table . It is also called a record . It is data sets representing attributes of a single item. A data model define how data are organized in database and how the data can be accessed. The...

The advantages of using a database rather than several separate files are:

Data redundancy: A database can store different types of data in different tables which can be related to one another, but these data will be stored multiple times if we plan to store these in different files. A database solves this by normalizing the data.

Easy access: A user can complex query data from a database. Separate files cannot be queried and would need a different program to do it.

Major responsibilities of a...

The purpose of E-R diagram are the database analyst/designer gains a better understanding of the information to be contained in the database through the process of constructing the E-R Diagram. The E-R Diagram serves as a documentation tool. Finally, The E-R Diagram is used to communicate the logical Structure of the database to users. In particular the logic of the database to users.

The different used in E-R diagram with their meaning are:

1.Rectangl:It represent the entity. It contains...

it is a data object used for documenting complex software system designs in a systematic diagram which makes them easy to understand.

Data modelling techniques:

Hierarchical Technique:

it is a treelike structure, which has a root node, and the other nodes originate from the initial root node, which is sorted in a particular order. this type of model is rarely used nowadays.

Object-oriented Model:

This approach creates objects with related data and allows advanced techniques like data abstraction,...

The benefits of Centralized Database are:

• It is simple to implement and manage.
• It has less or no risk of data loss.
• It has a low cost of implementation and operation.
• It is suitable for a small organization with limited data and users.
• High Security can be provided.