Conservapedia - User contributions [en]

Talk:Prime number

2008-01-10T16:28:39Z

Isaac4given: error testing primality of 4

== Primality testing - Problems with the number 4 ==

When testing whether a number ''N'' is divisible by ''s'', using values of ''s'' from 2 to ''N'' - 1, when ''N'' is 4, the method correctly determines that 4 is not prime, because it is divisible by 2. This example is in the C programming language.
<blockquote><pre>
for (s = 2; s < N - 1; ++s) {
if (N % s == 0) {
printf("N is not a prime number.");
}
}
</pre></blockquote>

However, when using values of ''m'' from 2 to the square root of ''n'', when ''n'' is 4, an error can occur. Since 2 is the square root of 4, the test range is 2 to 2, and, if the range is exclusive, as in a for-loop, the whole test is skipped, and 4 is incorrectly determined to be a prime number.
<blockquote><pre>
for (s = 2; s < sqrt(N); ++s) {
if (N % s == 0) {
printf("N is not a prime number.");
}
}
</pre></blockquote>

[[User:Isaac4given|Isaac4given]] 11:28, 10 January 2008 (EST)

Structured Query Language

2007-10-25T16:44:09Z

Isaac4given: sql transactions

SQL created by EF Codd at IBM (see his paper the relational model) is [[Structured Query Language]], a language for manipulating large data tables within a database. Most relational databases have SQL embedded within them. Users ask for the data they write a "[[database query|query]]" using SQL and the database quickly returns the data.

== Transactions ==

A transaction may include several SQL statements, but the statements are processed in an all-or-nothing fashion. The transaction represents logical work like a customer purchasing a product. For example, the statements may include adding the purchase price to the customer's account, and subtracting the product from inventory. If either statement is executed, they must both be executed, and if either statement is aborted, they must both be aborted. This is achieved by using the COMMIT statement and the ROLLBACK statement. Once all of the statements to execute for the current transaction have been entered, the COMMIT statement is entered, and the transaction is committed to the database. If any of the statements in the transaction cannot be completed, the entire transaction is rolled back, and none of the statements take effect.
[[Category:software]]

Database Management System

2007-09-16T23:23:27Z

Isaac4given: /* Definition */ expansion

== Definition ==
DBMS stands for [[Database]] Management System.

[[Category:Computer Science]]

== Functions ==

Data dictionary

2007-09-16T23:20:36Z

Isaac4given: more information

== Description ==

A '''data dictionary''' is a collection of [[database]] metadata, which is data about data. One kind of data dictionary is a human view of entities, attributes, and relationships, called a designer's data dictionary. There is usually a data dictionary that is internal to the [[DBMS]], called a system catalog, which contains additional system-generated metadata. A designer's data dictionary can be derived from the system catalog, and the terms "data dictionary" and "system catalog" are often used interchangeably.

== Purpose ==

The purpose of a data dictionary is to make sure that all of the people who design and implement the database are on the same page in light of the entities, attributes, and relationships.

== Database Designer's Database ==

A data dictionary is sometimes called a '''database designer's database''' because it defines choices made in light of [[database]] design of entities and their characteristics.

[[category:Computer Science]]

Database Management System

2007-09-14T21:02:10Z

Isaac4given: work was copyrighted

== Definition ==

== Functions ==

Database Management System

2007-09-14T21:01:47Z

Isaac4given: work was copyrighted

== Definition ==

== Functions ==

The functions of a DBMS include data dictionary management, data storage management, and data transformation and presentation. The functions also include security management, multiuser access control, backup and recovery management, data integrity management, database access languages and application programming interfaces, and database communication interfaces.

Database Management System

2007-09-14T20:27:22Z

Isaac4given: New page: == Definition == DBMS stands for database management system. A database management system is a collection of programs that manages the structure of databases and controls access to the da...

== Definition ==

DBMS stands for database management system. A database management system is a collection of programs that manages the structure of databases and controls access to the data stored in the databases.

== Functions ==

The functions of a DBMS include data dictionary management, data storage management, and data transformation and presentation. The functions also include security management, multiuser access control, backup and recovery management, data integrity management, database access languages and application programming interfaces, and database communication interfaces.

Data dictionary

2007-09-14T16:40:42Z

Isaac4given: New page: == Description == A data dictionary is a collection of database metadata, which is data about data. One kind of data dictionary is a human view of entities, attributes, and relationships,...

== Description ==

A data dictionary is a collection of database metadata, which is data about data. One kind of data dictionary is a human view of entities, attributes, and relationships, called a designer's data dictionary. There is usually a data dictionary that is internal to the DBMS, called a system catalog, which contains additional system-generated metadata. A designer's data dictionary can be derived from the system catalog, and the terms "data dictionary" and "system catalog" are often used interchangeably.

== Purpose ==

== Database Designer's Database ==