dcl in sql

Introduction of dcl in sql -: The full name of the dcl is Data Control Language. A data control language (dcl) is a syntax similar to a computer programming language used to control access to data stored in a database. In...

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internet databases

Internet Databases Introduction-: The expansion of internet and intranet enabled the user to access a large number of data sources available. One of major achievements of this expansion is E commerce which include purchasing of...

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index in sql

Index In sql :- An index is a schema object that can speed up the retrieval of rows by using a pointer. Indexes can be created explicitly or automatically. If we do mot have an index on the column, then a full table scan will...

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sequence in sql

Sequence in sql-: A sequence is a database object created by a user, and can be shared by multiple users to generate unique integers. We can use the sequence to automatically generate unique integers. A typical usage for...

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view in sql

Views in sql:-  We can present logical subsets or combination of data by creating views of tables. A view is a logical table based on a table or another view. A view contains no data of its own but is like a window through which...

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constraints in sql

Constraints in sql-: An integrity constraint can be thought of as a way to define a business rule for a column or a table. Integrity constraints are defined with a table and are stored as part of the table’s definition in...

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ddl

Data Definition Language (DDL)- In the previous post we read that the DDL is the part of SQL. It is the statement of sql . DDL is a standard for commands that define the different structures in a database. DDL statements create...

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subquery in sql

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...

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joins in sql

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...

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operator in sql

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...

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