Denormalization is the process of boosting up database performance and adding of redundant data which helps to get rid of complex data. Denormalization is a part of database optimization technique. This process is used to avoid the use of complex and costly joins. Denormalization doesn’t refer to the thought of not to normalize instead of that denormalization takes place after normalization. In this process, firstly the redundancy of the data will be removed using normalization process than through denormalization process…

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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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Can you explain the SELECT INTO Statement SELECT INTO statement is used mostly to create backups. The below SQL backsup the Employee table in to the EmployeeBackUp table. One point to be noted is that the structure of pcdsEmployeeBackup and pcdsEmployee table should be same. SELECT * INTO pcdsEmployeeBackup FROM pcdsEmployee What is SQL SQL stands for Structured Query Language.SQL is an ANSI (American National Standards Institute) standard computer language for accessing and manipulating database systems. SQL statements are used…

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Data Warehousing” is technical process where we are making our data centralized while “Data mining” is more of business activity which will analyze how good your business is doing or predict how it will do in the future coming times using the current data. As said before “Data Warehousing” is not a need for “Data mining”. It’s good if you are doing “Data mining” on a “Data Warehouse” rather than on an actual production database. “Data Warehousing” is essential when…

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The Data model is specified as a collection of conceptual tools for describing data, data relationships, data semantics and constraints. These models are used to describe the relationship between the entities and their attributes. There is the number of data models: Hierarchical data model network model relational model Entity-Relationship model and so on. A data model is a conceptual representation of how data is structured and organized within a database system. It defines the logical structure of the data and…

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Functional Dependency is the starting point of normalization. It exists when a relation between two attributes allow you to determine the corresponding attribute’s value uniquely. The functional dependency is also known as database dependency and defines as the relationship which occurs when one attribute in a relation uniquely determines another attribute. It is written as A->B which means B is functionally dependent on A.

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.

Can you explain Fourth Normal Form and Fifth Normal Form In fourth normal form it should not contain two or more independent multi-v about an entity and it should satisfy “Third Normal form”. Fifth normal form deals with reconstructing information from smaller pieces of information. These smaller pieces of information can be maintained with less redundancy. What is order by clause ORDER BY clause helps to sort the data in either ascending order to descending order. Ascending order sort query:…

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There are basically two types of indexes:- Clustered Indexes. Non-Clustered Indexes. In clustered index the non-leaf level actually points to the actual data.In Non-Clustered index the leaf nodes point to pointers (they are rowid’s) which then point to actual data. The correct answer to your question would be the difference between clustered and non-clustered indexes. Clustered Index: A clustered index determines the physical order of data rows in a table based on the indexed column(s). Each table can have only…

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A Relation Schema is specified as a set of attributes. It is also known as table schema. It defines what the name of the table is. Relation schema is known as the blueprint with the help of which we can explain that how the data is organized into tables. This blueprint contains no data. A relation is specified as a set of tuples. A relation is the set of related attributes with identifying key attributes See this example: Let r…

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