Techie Madness

A cursor can be explicit or implicit, and either type can be used in a FOR loop.  Why use an explicit cursor FOR loop over an implicit cursor FOR loop? Use an explicit cursor FOR loop when the query will be reused, otherwise an implicit cursor is preferred. Why use a loop with a FETCH rather than a FOR loop that doesn’t have an explicit FETCH? Use a FETCH inside a loop when you need to bulk collect or when you need dynamic SQL. Here is some useful information from the documentation. Example of Implicit Cursor FOR LOOP BEGIN FOR vItems IN ( SELECT last_name FROM employees WHERE manager_id > 120 ORDER BY last_name ) LOOP DBMS_OUTPUT . PUT_LINE ( 'Name = ' || vItems . last_name ); END LOOP ; END ; / Example of Explicit Cursor FOR LOOP DECLARE CURSOR c1 IS SELECT last_name FROM employees WHERE manager_id > 120 ORDER BY last_name ; BEGIN FOR vItems I...

View is a virtual table - It can be created on a table or another view. - It is just like a window through which we can access or change base table data. - It does contain data of its own. It always takes data from its base table. - It is stored as a query in data dictionary.Whenever you query a view it gets data from its based table using this query. Main advantage of using views - You can restrict access to predetermined set of rows and columns of a table - You can hide complexity of query  - You can hide complexity of calculation Synonym is alternate name given to table, view, sequence or program unit.  -It is used to mask real name and owner of the object.  - You can provide public access to tables by creating public synonyms.

Overview of Synonyms A  synonym  is an alias for any table, view, materialized view, sequence, procedure, function, package, type, Java class schema object, user-defined object type, or another synonym. Because a synonym is simply an alias, it requires no storage other than its definition in the data dictionary. Synonyms are often used for security and convenience. For example, they can do the following: Mask the name and owner of an object Provide location transparency for remote objects of a distributed database Simplify SQL statements for database users Enable restricted access similar to specialized views when exercising fine-grained access control You can create both public and private synonyms. A  public  synonym is owned by the special user group named  PUBLIC  and every user in a database can access it. A  private  synonym is in the schema of a specific user who has control over its availability to others. Synonyms ...