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Codd introduced the concept of normalization and what is now known as the first normal form (1NF) in 1970. [4] Codd went on to define the second normal form (2NF) and third normal form (3NF) in 1971, [5] and Codd and Raymond F. Boyce defined the Boyce–Codd normal form (BCNF) in 1974. [6]
Second normal form (2NF), in database normalization, is a normal form. A relation is in the second normal form if it fulfills the following two requirements: A relation is in the second normal form if it fulfills the following two requirements:
This rule allows one to express a joint probability in terms of only conditional probabilities. [4] The rule is notably used in the context of discrete stochastic processes and in applications, e.g. the study of Bayesian networks, which describe a probability distribution in terms of conditional probabilities.
Reducing the cost of software maintenance is the most often cited reason for following coding conventions. In the introductory section on code conventions for the Java programming language, Sun Microsystems offers the following reasoning: [2]
First normal form (1NF) is a property of a relation in a relational database. A relation is in first normal form if and only if no attribute domain has relations as elements. [ 1 ] Or more informally, that no table column can have tables as values.
Even if you provide a mathematical definition of 1NF, being in 1NF will be independent from being in 2NF. The quote from the article is wrong if 1NF is included. 2NF and higher are defined mathematically, and these definitions are such that for each i > j > 1, every database in iNF is also in jNF. Hence, for all NFs above 1, the quote is correct.
Like natural languages, programming languages follow rules for syntax and semantics. There are thousands of programming languages [ 1 ] and new ones are created every year. Few languages ever become sufficiently popular that they are used by more than a few people, but professional programmers may use dozens of languages in a career.
The Java language is designed to enforce type safety. Anything in Java happens inside an object and each object is an instance of a class. To implement the type safety enforcement, each object, before usage, needs to be allocated. Java allows usage of primitive types but only inside properly allocated objects.