ACID properties are some basic rules, which has to be satisfied by every transaction to preserve the integrity. These properties and rules are: ATOMICITY: Atomicity is more generally known as ?all or nothing rule.’ Which implies all are considered as one unit, and they either run to completion or not executed at all. CONSISTENCY: This property refers to the uniformity of the data. Consistency implies that the database is consistent before and after the transaction. ISOLATION: This property states that…

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BCNF stands for Boyce-Codd Normal Form. It is an advanced version of 3NF, so it is also referred to as 3.5NF. BCNF is stricter than 3NF. A table complies with BCNF if it satisfies the following conditions: It is in 3NF. For every functional dependency X->Y, X should be the super key of the table. It merely means that X cannot be a non-prime attribute if Y is a prime attribute.

3NF stands for Third Normal Form. A database is called in 3NF if it satisfies the following conditions: It is in second normal form. There is no transitive functional dependency. For example: X->Z Where: X->Y Y does not -> X Y->Z so, X->Z 3NF stands for Third Normal Form, which is a normalization technique used in database design to reduce redundancy and improve data integrity. In 3NF: The table must be in 2NF (Second Normal Form). All non-prime attributes (attributes…

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2NF is the Second Normal Form. A table is said to be 2NF if it follows the following conditions: The table is in 1NF, i.e., firstly it is necessary that the table should follow the rules of 1NF. Every non-prime attribute is fully functionally dependent on the primary key, i.e., every non-key attribute should be dependent on the primary key in such a way that if any key element is deleted, then even the non_key element will still be saved…

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1NF is the First Normal Form. It is the simplest type of normalization that you can implement in a database. The primary objectives of 1NF are to: Every column must have atomic (single value) To Remove duplicate columns from the same table Create separate tables for each group of related data and identify each row with a unique column

he Join operation is one of the most useful activities in relational algebra. It is most commonly used way to combine information from two or more relations. A Join is always performed on the basis of the same or related column. Most complex queries of SQL involve JOIN command. There are following types of join: Inner joins: Inner join is of 3 categories. They are: Theta join Natural join Equi join Outer joins: Outer join have three types. They are:…

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Data independence specifies that “the application is independent of the storage structure and access strategy of data.” It makes you able to modify the schema definition at one level without altering the schema definition in the next higher level. It makes you able to modify the schema definition in one level should not affect the schema definition in the next higher level. There are two types of Data Independence: Physical Data Independence: Physical data is the data stored in the…

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System R was designed and developed from 1974 to 1979 at IBM San Jose Research Centre. System R is the first implementation of SQL, which is the standard relational data query language, and it was also the first to demonstrate that RDBMS could provide better transaction processing performance. It is a prototype which is formed to show that it is possible to build a Relational System that can be used in a real-life environment to solve real-life problems. Following are…

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Extension: The Extension is the number of tuples present in a table at any instance. It changes as the tuples are created, updated and destroyed. The actual data in the database change quite frequently. So, the data in the database at a particular moment in time is known as extension or database state or snapshot. It is time dependent. Intension: Intension is also known as Data Schema and defined as the description of the database, which is specified during database…

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Data integrity is one significant aspect while maintaining the database. So, data integrity is enforced in the database system by imposing a series of rules. Those set of integrity is known as the integrity rules. There are two integrity rules in DBMS: Entity Integrity : It specifies that “Primary key cannot have a NULL value.” Referential Integrity: It specifies that “Foreign Key can be either a NULL value or should be the Primary Key value of other relation