Database Programming

Template

data communication link

#include<stdio.h>

int main ()

{

printf ("2 4 6 8 10 12 14 16 18 20");

return 0;

}

By listening for a special signal known as Beacon Frame.

Network + Guide to Networks. page 375

accumulated other comprehensive income

The relational model is a model in which data is isolated by object and foreign keys to those objects which is organized in tables with multiple columns or attributes. The hierarchical model is a model in which the data is organized in a tree structure that allows repeating information using parent/child relationships.

In Data Entry, KPH would mean keystrokes per hour, with 'Net' referring to the overall keystrokes minus errors. Just like a paycheck represents a 'net' income minus deductions, Net KPH reduces your overall accuracy rate per hour.

flat file

u ust type in buddylovesme

More than one record in a Database

Product - Level Activities relate to specific products and typically must be carried out regardless of how many batches are run or units of product are produced of sold. For example, activities suck as designing a product, advertising a product, and maintaining a product manager and staff are all product -level activities.

Managerial Accounting, 14th Edition, Garrison, (2012)

On the stack; they are addressed via register SP or BP.

Advantage:

Spread Sheets are basically giant Powerful Calculators

Disadvantage:

If you do one formulae wrong the whole spreadsheet will go wrong and you may have to start again

First make a table of values, then draw axes and label them appropriately

Then plot points carefully, and join with a curve or line (the particular way of drawing the line depends on the type of graph: scientific, scatter or mathematical.)

Scientific graphs have values resulting from experiments. You draw a curve that follows the general trend of the points. (And passes within experimental error of the points) Scatter graphs are plotted with a straight line of best fit. Mathematical graphs should be joined with curves that pass exactly through the points.

Database Mirroring-->

Extend log shipping capabilities with the database mirroring solution. You will be able to use database mirroring to enhance availability of your SQL Server systems by setting up automatic failover to a standby server.

Online Restore-->

With SQL Server 2005, database administrators are able to perform a restore operation while an instance of SQL Server is running. Online restore improves the availability of SQL Server because only the data being restored is unavailable; the rest of the database remains online and available.

Online Indexing Operations-->

The online index option allows concurrent modifications (updates, deletes, and inserts) to the underlying table or clustered index data and any associated indexes during index data definition language (DDL) execution. For example, while a clustered index is being rebuilt, you can continue to make updates to the underlying data and perform queries against the data.

Fast Recovery-->

A new faster recovery option improves availability of SQL Server databases. Administrators can reconnect to a recovering database after the transaction log has been rolled forward.

A BD ROM stands for Blu-ray Disc-ROM and has storage capacities of 100GB with expectations of exceeding 200GB in the near future.

This model helps you to get everything to work together. You can bring in little details and not worry about them getting lost.

Yes Foreign key can have null value.

Data can be transferred in 3 different modes, these 3 modes are equally popular and used in common everyday situations.

•Simplex

If data can only be transferred in a single direction (one way) it is known as simplex. Television transmission is an example of Simplex transmission, here data can be transferred only to a television but no data can be transferred in the opposite direction.

•Duplex

When data maybe transferred in two directions simultaneously it is known as Duplex, a simple telephone conversation would be an example, while we usually don't talk simultaneously a telephone provides that 'duplex' functionality.

•Half-Duplex

In this mode of transmission as well, data maybe transmitted in both directions, however it cannot be done simultaneously. A Walkie Talkie would be an example of this mode of transmission.

The different modes are implemented based on their requirements, for example in Simplex transmission, two way transmission is not required in television transmission thus Simplex is used.

A weak entity set can always be make into strong entity set by adding to its attribute of its identifying entity set. For a weak entity set, we add columns to the table corresponding to the primary key of the strong entity set on which the weak set is dependent.

to manipulate the masterfile tables through the use and methods of stenographic software and watermark programing installs.

1 Explain architecture of Distributed Database systems? Also, explain the reasons for building distributed database systems?

View is a virtual table with no data , but can be operated like any other table. It is like a virtual table through which you can view data of another table, which is known as the base table. Syntax for creating a view- CREATE VIEW as SELECT statement ;

It depends on the DBMS

MSSQL: SELECT TOP 1 column FROM table

MySQL: SELECT column FROM table LIMIT 0,1 (start index, number of rows to get)

DBMS (Database Management System) acts as an interface between the user and the database. The user requests the DBMS to perform various operations (insert, delete, update and retrieval) on the database. The components of DBMS perform these requested operations on the database and provide necessary data to the users. The various components of DBMS are shown below: -

Fig. 2.1 Structure Of DBMS

1. DDL Compiler - Data Description Language compiler processes schema definitions specified in the DDL. It includes metadata information such as the name of the files, data items, storage details of each file, mapping information and constraints etc.

2. DML Compiler and Query optimizer - The DML commands such as insert, update, delete, retrieve from the application program are sent to the DML compiler for compilation into object code for database access. The object code is then optimized in the best way to execute a query by the query optimizer and then send to the data manager.

3. Data Manager - The Data Manager is the central software component of the DBMS also knows as Database Control System.

The Main Functions Of Data Manager Are: --

• Convert operations in user's Queries coming from the application programs or combination of DML Compiler and Query optimizer which is known as Query Processor from user's logical view to physical file system.

• Controls DBMS information access that is stored on disk.

• It also controls handling buffers in main memory.

• It also enforces constraints to maintain consistency and integrity of the data.

• It also synchronizes the simultaneous operations performed by the concurrent users.

• It also controls the backup and recovery operations.

4. Data Dictionary - Data Dictionary is a repository of description of data in the database. It contains information about

• Data - names of the tables, names of attributes of each table, length of attributes, and number of rows in each table.

• Relationships between database transactions and data items referenced by them which is useful in determining which transactions are affected when certain data definitions are changed.

• Constraints on data i.e. range of values permitted.

• Detailed information on physical database design such as storage structure, access paths, files and record sizes.

• Access Authorization - is the Description of database users their responsibilities and their access rights.

• Usage statistics such as frequency of query and transactions.

Data dictionary is used to actually control the data integrity, database operation and accuracy. It may be used as a important part of the DBMS.

Importance of Data Dictionary -

Data Dictionary is necessary in the databases due to following reasons:

• It improves the control of DBA over the information system and user's understanding of use of the system.

• It helps in documentating the database design process by storing documentation of the result of every design phase and design decisions.

• It helps in searching the views on the database definitions of those views.

• It provides great assistance in producing a report of which data elements (i.e. data values) are used in all the programs.

• It promotes data independence i.e. by addition or modifications of structures in the database application program are not effected.

5. Data Files - It contains the data portion of the database.