E-R model is a short name for the Entity-Relationship model. This model is based on the real world. It contains necessary objects (known as entities) and the relationship among these objects. Here the primary objects are the entity, attribute of that entity, relationship set, an attribute of that relationship set can be mapped in the form of E-R diagram. In E-R diagram, entities are represented by rectangles, relationships are represented by diamonds, attributes are the characteristics of entities and represented…

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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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What is Data Warehousing Data Warehousing is a process in which the data is stored and accessed from central location and is meant to support some strategic decisions. Data Warehousing is not a requirement for Data mining. But just makes your Data mining process more efficient. Data warehouse is a collection of integrated, subject-oriented databases designed to support the decision-support functions (DSF), where each unit of data is relevant to some moment in time. What is the default “-SORT” order…

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The degree of relation is a number of attribute of its relation schema. A degree of relation is also known as Cardinality it is defined as the number of occurrence of one entity which is connected to the number of occurrence of other entity. There are three degree of relation they are one-to-one(1:1), one-to-many(1:M), many-to-one(M:M). The degree of a relation in a database management system (DBMS) refers to the number of attributes or columns in a relation (table). So, the…

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The Entity is a set of attributes in a database. An entity can be a real-world object which physically exists in this world. All the entities have their attribute which in the real world considered as the characteristics of the object. For example: In the employee database of a company, the employee, department, and the designation can be considered as the entities. These entities have some characteristics which will be the attributes of the corresponding entity.

A stored procedure is a group of SQL statements that have been created and stored in the database. The stored procedure increases the reusability as here the code or the procedure is stored into the system and used again and again that makes the work easy, takes less time in processing and decreases the complexity of the system. So, if you have a code which you need to use again and again then save that code and call that code…

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What are indexes? What are B-Trees Index makes your search faster. So defining indexes to your database will make your search faster.Most of the indexing fundamentals use “B-Tree” or “Balanced-Tree” principle. It’s not a principle that is something is created by SQL Server or ORACLE but is a mathematical derived fundamental.In order that “B-tree” fundamental work properly both of the sides should be balanced. What is a Sub-Query A query nested inside a SELECT statement is known as a subquery…

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The Relationship is defined as an association among two or more entities. There are three type of relationships in DBMS- One-To-One: Here one record of any object can be related to one record of another object. One-To-Many (many-to-one): Here one record of any object can be related to many records of other object and vice versa. Many-to-many: Here more than one records of an object can be related to n number of records of another object.

An entity type is specified as a collection of entities, having the same attributes. Entity type typically corresponds to one or several related tables in the database. A characteristic or trait which defines or uniquely identifies the entity is called entity type. For example, a student has student_id, department, and course as its characteristics. An entity type in a database management system (DBMS) refers to a category of similar entities that share common attributes. It represents a class of objects…

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DELETE command: DELETE command is used to delete rows from a table based on the condition that we provide in a WHERE clause. DELETE command delete only those rows which are specified with the WHERE clause. DELETE command can be rolled back. DELETE command maintain a log, that’s why it is slow. DELETE use row lock while performing DELETE function. TRUNCATE command: TRUNCATE command is used to remove all rows (complete data) from a table. It is similar to the…

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