Introduction In this article a number of methods which can be castoff for database recovery from failures are discussed. The various reasons of database failures are already to known to us, like system crashes in addition to transaction faults. The very first section of the article will be outlining the usual recovery techniques as well as the classification of recovery...

Lossless – Join Decomposition In this article so far normalization of a number of relations or tables has been done by means of decomposing them. Table or relation has been decomposed instinctively. At this point of time a better understanding for determining decompositions as instinct might not always be precise. Over here, an illustration is given as an instance for...

Third (3rd) Normal Form The second normal form (2NF) tables or relation that was recognized in the preceding section signify an important enhancement over first normal form (1NF) relation or tables. But, the tables still suffer from the similar kinds of irregularities as the first normal form (1NF) relation or tables even though for various causes related with transitive dependencies....

Second (2nd) Normal Form To clarify the notion of second normal form (2NF) as well as advanced normal forms, an individual should know the idea of practical dependence. The property of one (1) or more (N) columns or attributes which individually regulate the data of one (1) or more (N) other attributes or columns is known as practical dependence. Given...

First (1st) Normal Form A table or relation is said to be in first normal form (1NF) only when every attribute or column has only atomic data in them, which is every single attributes or column can have only one (1) data for every single tuple or row in the relation or table. Relational database tables, like the Sales table...

Notion of Multi Valued Dependency (MVD) The multi valued dependency (MVD) X → Y is supposed to hold for a table or relation R ( X, Y, Z ) if for a given group of data (group of data when X is having more than one (1) column or attribute) for columns or attributes X, there is a group of...

Multi – Valued Dependencies The multi valued dependency arises when more than one (1) multi valued attributes or columns are existing. Think through the subsequent relation or table which signifies an object EMPLOYEE which has one (1) multi valued column or attribute named as “Projects”. EMPLOYEE ( Emp_ID, Department, Projects, Salary) To this point of time the data or the...

Relational Database Management System (RDBMS) and Normalization Forms – Part – 4 Irreducible Sets of Dependencies Let’s assume S 1 as well as S 2 be two (2) sets of practical dependencies if every single practical dependencies inferred by means of S 1 is inferred through S 2 which is when S 1 + is a subclass of S 2...

Relational Database Management System (RDBMS) and Normalization Forms – Part – 3 Minor Practical Dependencies In addition to classifying practical dependencies which hold for every likely data of the column or attributes involved in the practical dependencies, an individual may desire to take no notice of unimportant practical dependencies. A practical dependency is insignificant when the resulting is a subsection...

Relational Database Management System (RDBMS) and Normalization Forms – Part – 2 Decompositions Automatically, redundancy rises as soon as a relational schema forces a relationship among attributes or columns which is not normal. Practical dependencies can be castoff to recognize such circumstances as well as to recommend modifications to the schema. The necessary notion is that numerous difficulties rising from...