CLIENT/SERVER-Sql Interview Questions and Answers

What does preemptive in preemptive multitasking mean ?

Preemptive refers to the fact that each task is alloted fixed time slots and at the end of that time slot the next task is started.

What does the OLTP stands for ?
OLTP stands for On Line Transaction Processing

What is the most important requirement for OLTP ?
OLTP requires real time response.
In a client server environment, what would be the major work that the client deals with ? The client deals with the user interface part of the system.
Why is the most of the processing done at the sever ?
To reduce the network traffic and for application sharing and implementing business rules.
What does teh term upsizing refer to ?
Applications that have outgrown their environment are re-engineered to run in a larger environment. This is upsizing.
What does one do when one is rightsizing ?
With rightsizing, one would move applications to the most appropriate server platforms.
What does the term downsizing refer to ?
A host based application is re-engineered to run in smaller or LAN based environment.
What is event trigger ?
An event trigger, a segment of code which is associated with each event and is fired when the event occurs.
Why do stored procedures reduce network traffic ?
When a stored procedure is called, only the procedure call is sent to the server and not the statements that the procedure contains.
What are the types of processes that a server runs ?
Foreground process and Background process.
What is a event handler ?
An event handler is a routine that is written to respond to a particular event.
What is an integrity constraint ?
An integrity constraint allows the definition of certain restrictions, at the table level, on the data that is entered into a table.

What are the various uses of database triggers ?
Database triggers can be used to enforce business rules, to maintain derived values and perform value-based auditing.
What is a transaction ?
A transaction is a set of operations that begin when the first DML is issued and end when a commit or rollback is issued. BEGIN COMMIT/ROLLBACK are the boundries of a transaction.
Why are the integrity constraints preferred to database triggers ?
Because it is easier to define an integrity constraint than a database trigger.
Why is it better to use an integrity constraint to validate data in a table than to use a stored procedure ?
Because an integrity constraint is automatically checked while data is inserted into a table. A stored has to be specifically invoked.
What are the three components of a client server model ?
A Client, A Server and A Network/Communication software.
What are the advantages of client/server model ?
Flexibility of the system, scalability, cost saving, centralised control and implementation of business rules, increase of developers productivity, portability, improved network and resource utilization.
What are the disadvantages of the client/server model ?
Heterogeneity of the system results in reduced reliability. May not be suitable for all applications. Managing and tuning networks becomes difficult.
What are the different topologies available for network ?
Star, Bus, Ring.
What is the first work of Client process ?
A client process at first establishes connection with the Server.
What are the responsibilities of a Server ?
1. Manage resources optimally across multiple clients.
2. Controlling database access and security.
3. Protecting the database and recovering it from crashes.
4. Enforcing integrity rules globally.
In a Client/Server context, what does API (Application Programming Interface) refer to ? An API, in a Client/Server context, is a specification of a set of functions for communication between the client and the server.
Give some examples of standard API?? Open Database Connectivity (ODBC), Integrated Database Application Programming Interface (IDAPI), XOpen SQL/CLI
What is the main advantage of developing an application using an API ?
The application can be connected to any back end server that is supported by the API.
What is the main disadvantage of developing an application using an API ?
The application cannot use any special features of the backend server.
Why is an event driven program referred to a passive program ?
Because an event driven program is always waiting for something to happen before processing.
What are the four types of events ?
1. System Events.
2. Control Events
3. User Events
4. Other Events.
What is the difference between file server and a database server ?
A file server just transfers all the data requested by all its client and the client processes the data while a database server runs the query and sends only the query output.

What is inheritance ?
Inheritance is a method by which properties and methods of an existing object are automatically passed to any object derived from it.

What are the two components of ODBC ?
1. An ODBC manager/administrator and
2. ODBC driver.

What is the function of a ODBC manager ?
The ODBC Manager manages all the data sources that exists in the system.
What is the function of a ODBC Driver ?
The ODBC Driver allows the developer to talk to the back end database.
What description of a data source is required for ODBC ?
The name of the DBMS, the location of the source and the database dependent information.
How is a connection established by ODBC ?
ODBC uses the description of the datasource available in the ODBC.INI file to load the required drivers to access that particular back end database.