Database Programming

In a database system, it means validity of your existing data. it refers whether your data is correct or not, only one mistake while entering data can lead it to corrupt data. some protocols are used to get rid of wrong data such as input mask.

E.g. while entering "dates" someone can write date in the way 01-02-2012, some other can write the same date in this order 02-01-2012 and it is also can be written in full February 01, 2012. so this can spoil record and also while making query you might get incomplete or wrong data. this is the reason it is most important in a database system.

Physical abstraction in data abstraction refers to hiding the implementation details of how data is stored and accessed. It allows programmers to work with high-level concepts of data without needing to understand the underlying physical structures. This separation enhances modularity and simplifies the complexity of software systems.

No

Assuming you are asking from a business perspective, and you are the person entering all the data into the database, sometimes it seems unending and trivial; but it is not. A correct and accurate database may serve a company greatly. If access to names, addresses, and phone number are provided to sales, they become opportunities for new sales. When analysed by statistical departments they can tell management when and where your product(s) do best, what age groups they appeal to, what appears to be a "sweet spot" on pricing, but most importantly, complete analysis is needed to report to the board sales figures and profit; either gross or net. While you may not see any of these reports, what you input into that database impacts all of these things!

maps are showing different information are placed on top of each other

Indeed, I am...

A multi-list is really only a slightly modified inverted file. There is one list per keyword, i.e. hi = 1. The records containing a particular keyword Ki are chained together to form the Ki-list and the start of the Ki-list is given in the directory, as illustrated in Figure 4.6. Since there is no K3-list, the field reserved for its pointer could well have been omitted. So could any blank pointer field, so long as no ambiguity arises as to which pointer belongs to which keyword. One way of ensuring this, particularly if the data values (attribute-values) are fixed format, is to have the pointer not pointing to the beginning of the record but pointing to the location of the next pointer in the chain.

The multi-list is designed to overcome the difficulties of updating an inverted file. The addresses in the directory of an inverted file are normally kept in record-number order. But, when the time comes to add a new record to the file, this sequence must be maintained, and inserting the new address can be expensive. No such problem arises with the multi-list, we update the appropriate K-lists by simply chaining in the new record. The penalty we pay for this is of course the increase in search time. This is in fact typical of many of the file structures. Inherent in their design is a trade-off between search time and update time.

A subquery in DBMS is a query nested within another query. It is a way to retrieve data that depends on the result of another query. Subqueries can be used in a variety of ways, such as filtering, joining, or defining a derived table.

3 Main reasons:

1.OLTP systems require high concurrency, reliability, locking which provide good performance for short and simple OLTP queries. An OLAP query is very complex and does not require these properties. Use of OLAP query on OLTP system degrades its performance.

2.An OLAP query reads HUGE amount of data and generates the required result. The query is very complex too. Thus special primitiveshave to provided to support this kind of data access.

3.OLAP systems access historical data and not current volatile data while OLTP systems access current up-to-date data and do not need historical data.

field, record, table, database

A Database is a Software that is used For Storing The Data For Further Use.

SimpleDB

DISTINCT

by using drawing techniques

Since a user can define a views, logical data independence can achieved by using view definition to hide changes in the conceptual schema.

since the sql user has no knowledge of how the data is physically represented, relying solely on the relation abstraction for querying, physical data independence is also achieved.

Yes, you input the info and it can tell you where a company has profited or needs to improve on quality control etc.

It is the process of integrating system together to achieve a goal, eg. DBMS

Developing a database application means converting your data into types understood by the DBMS, generating SQL code, sending it to the DBMS for evaluation, retrieving the result, and converting the result into types understood by your application language. It's even more strange when you use parameterized SQL: you generate some code with placeholders instead of literals, and then you send the literals separately (by "more strange," I certainly don't mean "worse," - parameterized SQL is a huge improvement).

Objectives of information Security and control=

1. To prevent unauthorized access to the location.

2. to prevent confidentiality of data.

3. To provide disaster recovery system.

4. prevention of malicious damage.

5. prevention of prevention from accidental damage.

Characteristics of IS&c=

1.Integrity=A system functions as intended then it is considered to have integrity.

So the system designers make such a system that can work even if one or more components do not work.

2.Auditability=Easy to examine,verify,and demonstrate the performance of a system.

3.Controlability=helps management to have control over use and content of a system.

Data inconsistency

To Store records of information

SqlDataReader

To select particular data at particular situation.