What are transaction isolation levels supported by Oracle?

Correct Answer: A database trigger is procedural code that is automatically executed in response to certain events on a particular table or view in a database The trigger is mostly used for maintaining the integrity of the information on the database Syntax: CREATE OR REPLACE TRIGGER [Trigger Name] [Before / After / Instead Of] ON [schema][table] Types of PL/SQL triggers : > Row trigger - The trigger fires for each ROW affected > Statement trigger - The trigger is fired once when the condition is matched > Before and After trigger - The BEFORE trigger run the trigger action before the insert, update or delete statement The AFTER trigger runs the trigger action after the insert, update or delete statement is executes

Correct Answer: Named PL/SQL blocks of code which can be invoked using parameters are called PL/SQL sub programs Advantages of PL/SQL subprograms are - The application makes a single call to the database to run a block of statements which improves performance against running SQL multiple times This will reduce the number of calls between the database and the application - PL/SQL is secure since the code resides inside the database thus hiding internal database details from the application The application will only make a call to the PL/SQL sub program - PL/SQL and SQL go hand in hand so there would be no need of any translation required between PL/SQL and SQL

Correct Answer: Cursors help you manipulate the information retrieved by select statements This can be done by assigning a name to the cursor Example: CURSOR emp_cur IS SELECT emp_number from employee_tbl where employee_name = name_in; Types of Cursors: Implicit cursors- These cursors are not declared by the programmer They are issued when the SQL statement is executed The open, close and fetching is done by itself Example: UPDATE employee SET salary = salary * 21; Here, an implicit cursor is issued to identify the set of rows in the table which would be affected by the update Explicit cursors- These cursors are defined by programmer They are used in queries that return multiple rows Example: CURSOR emp_cur IS SELECT emp_number from employee_tbl where employee_name = name_in;

Correct Answer: - Mask the real name and owner of an object - Provide public access to an object - Provide location transparency for tables, views or program units of a remote database - Simplify the SQL statements for database users

Correct Answer: ANALYZE command is used to perform various functions on index, table, or cluster, as listed below: - It helps in dentifying migrated and chained rows of the table or cluster - It helps in validating the structure of the object - It helps in collecting the statistics about object used by the optimizer They are then stored in the data dictionary - It helps in deleting statistics used by object from the data dictionary

Correct Answer: Insert image into a table Create the following table: create table pics_table ( bfile_id number, bfile_desc varchar2(30), bfile_loc bfile, bfile_type varchar2(4)) TABLESPACE appl_data storage (initial 1m next 1m pctincrease 0) Insert Query: INSERT INTO pics_table VALUES(4,'test image',bfilename('GIF_FILES','TestJPG'),'JPEG');

Correct Answer: All the above

Correct Answer: DocumentDB is a NoSQL document-oriented database and records saves in key-value pairs It's same as the other NoSQL document-oriented such as MongoDB

Correct Answer: 12

Explanation:

We can apply at max of 12 triggers in a table.

Correct Answer: PATH and CLASSPATH are operating system level environment variables PATH is used to define where the system can find the executables (exe) files whereas CLASSPATH is used to specify the location of class files