Some SQL Server Definitions
Most of the definitions provided here are taken from SQL Server 2000 books and Documentation.
What is normalization?
A relational database is basically composed of tables that contain related data. So the Process of organizing this data into tables is actually referred to as normalization.
What is a Stored Procedure?
It is a set of T-SQL statements combined to perform a single task of several tasks and stored in compiled state in SQL server.
What is a trigger?
Triggers are basically used to implement business rules. Triggers is also similar to stored procedures. The difference is that it can be activated when data is added or edited or deleted from a table in a database.
What is a view?
A view can be thought of as either a virtual table or a stored query. The data accessible through a view is not stored in the database as a distinct object. What is stored in the database is a SELECT statement. The result set of the SELECT statement forms the virtual table returned by the view. A user can use this virtual table by referencing the view name in Transact-SQL statements the same way a table is referenced. (Source - SQL Server books online)
What is an Index?
An index is a structure that orders the values of one or more columns in a database table, for example the last name (lname) column of the employee table. If you were looking for a specific employee by his or her last name, the index would help you get that information faster than if you had to search all the rows in the table.The index provides pointers to the data values stored in specified columns of the table, and then orders those pointers according to the sort order you specify.
What is a Clustered Index?
An index in which the logical order of the key values determines the physical order of the corresponding rows in a table.
What is a Non-Clustered Index?
An index in which the logical order of the index is different than the physical, stored order of the rows on disk.
What are Cursors?
Set of rows returned by a SELECT statement is called result-set. Cursors are an extension provided to result-set.
Cursors extend result processing by:
- Allowing positioning at specific rows of the result set.
- Retrieving one row or block of rows from the current position in the result set.
- Supporting data modifications to the rows at the current position in the result set.
- Supporting different levels of visibility to changes made by other users to the database data that is presented in the result set.
- Providing Transact-SQL statements in scripts, stored procedures, and triggers access to the data in a result set.
Whats is HAVING Clause and Where it is used?
HAVING clause specifies a search condition for a group or an aggregate. HAVING can be used only with the SELECT statement. It is usually used in a GROUP BY clause. When GROUP BY is not used, HAVING behaves like a WHERE clause.
What is normalization?
A relational database is basically composed of tables that contain related data. So the Process of organizing this data into tables is actually referred to as normalization.
What is a Stored Procedure?
It is a set of T-SQL statements combined to perform a single task of several tasks and stored in compiled state in SQL server.
What is a trigger?
Triggers are basically used to implement business rules. Triggers is also similar to stored procedures. The difference is that it can be activated when data is added or edited or deleted from a table in a database.
What is a view?
A view can be thought of as either a virtual table or a stored query. The data accessible through a view is not stored in the database as a distinct object. What is stored in the database is a SELECT statement. The result set of the SELECT statement forms the virtual table returned by the view. A user can use this virtual table by referencing the view name in Transact-SQL statements the same way a table is referenced. (Source - SQL Server books online)
What is an Index?
An index is a structure that orders the values of one or more columns in a database table, for example the last name (lname) column of the employee table. If you were looking for a specific employee by his or her last name, the index would help you get that information faster than if you had to search all the rows in the table.The index provides pointers to the data values stored in specified columns of the table, and then orders those pointers according to the sort order you specify.
What is a Clustered Index?
An index in which the logical order of the key values determines the physical order of the corresponding rows in a table.
What is a Non-Clustered Index?
An index in which the logical order of the index is different than the physical, stored order of the rows on disk.
What are Cursors?
Set of rows returned by a SELECT statement is called result-set. Cursors are an extension provided to result-set.
Cursors extend result processing by:
- Allowing positioning at specific rows of the result set.
- Retrieving one row or block of rows from the current position in the result set.
- Supporting data modifications to the rows at the current position in the result set.
- Supporting different levels of visibility to changes made by other users to the database data that is presented in the result set.
- Providing Transact-SQL statements in scripts, stored procedures, and triggers access to the data in a result set.
Whats is HAVING Clause and Where it is used?
HAVING clause specifies a search condition for a group or an aggregate. HAVING can be used only with the SELECT statement. It is usually used in a GROUP BY clause. When GROUP BY is not used, HAVING behaves like a WHERE clause.
Labels: SQL Server, T-SQL
posted by Raj Kiran Singh at
2:41 PM
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