Full stack developer definition -: Full stack developer is a person who has enough knowledge and experience in the both developing technology front end and back end development. In other words we can say that Full stack development refers to the development of both front end and back end portions of an application. Scope of Full Stack… Read More »
Subquery in sql-: Suppose we want ti write a query to find out who earns a salary more then Rames’s salary. To solve this problem we need two query first find out the Ramesh salary and second who earn more then Ramesh. we can solve this problem by combine two query placing one query inside… Read More »
SQL Joins -: Display data from multiple tables in sql called the joins. In other words we can say when data from more then one table in database is required a join condition is use there. In one table row is Joined to another table row according to common value existing in corresponding column. as… Read More »
Limiting rows using a selection in sql -: We can restrict the row returned the query by using the where clause as like this Select [Distinct] {* ! column [alias], ….} from table {where condition(S)]; In this syntax : Where – The where clause can compare value in column literal value arithmetic expression or function. It… Read More »
Select Statement-:A select statement retrieves information from the database. Using a SELECT statement, We can do the following: Select : We can use the selection capability in SQL to choose the rows in a table that we want returned by a query. We can use various criteria to selectively restrict the rows that we see.… Read More »
introduction- SQL means structure query language.To access the database, we execute a Structured Query Language (SQL) statement, which is the American National Standards Institute (ANSI) standard language for operating upon relational database. The language contains a large set of operators for partitioning and combining relations. the database can be modified using the SQL statements. Non-Procedural… Read More »
Introduction -: Now a days relation data model is being used as the primary model for commercial data processing application. It was introduced by E.F.Codd in 1970 and it changed permanently the way people viewed database. The relation model is based on logical relationship between data and allows user to be totally unconcerned with or… Read More »
Convert ER model into relation schema . There are well defined rules for this conversion. These are Converting strong Entity type Converting weak entity types Converting relationships Converting specialization Converting aggregation. Converting strong entity types- Each entity become a table Each single valued attribute becomes a column Derived attribute are ignored. Composite attribute are represented… Read More »
The Entity Relationship Model has describe some following steps are available here. There are Identify the entity Identify the attribute Find the relationship Identify other relevant attribute Draw complete E-R Diagram with all attribute including primary key For understating these steps complete we take a example of a college database .. A collage… Read More »
There are many important features are available in extended features of E R model.These are .. Superclass and Subclass Specialization Generalization Condition defined v/s User defined Disjoint vs Overlapping Total vs Partial specialization … Read More »