What is the difference between a Rollback Command and a Commit Command?Ī Commit command is used to save the current transaction in the database in which modification is done to the database using Database Manipulation Language (DML) commands. The Syntax is: raise_application_error(Error Code, Error Message) The parameters are: Error Code and an Error Message. What are the Parameters for raise_application_errror()? %rowtype will automatically change its datatype to the one in the database. This is used if you want to create new variable which needs to fetch in a variable value from the database and you don’t know the Datatype of that variable. You can take it using the Input Operator. How can you take an Input from a User of the Database? These are Atomicity, Consistency, Isolation and Durability. The properties of a Database are also known as ACID Properties. We cannot control the execution of a Trigger whereas a Stored Procedure Execution can be controlled by the programmer. Describe the disadvantage of Database Trigger over Stored Procedures? Trigger Action, Trigger Restriction and Trigger Action are the different components of a PL/SQL Trigger. What are the different components of a PL/SQL trigger? In, Out and In-Out are different modes of a PL/SQL Procedure. What are the modes of parameters in a PL/SQL Procedure? What is the basic difference between a Procedure and a Function?īoth Procedures and Functions have the capability of accessing parameters but Functions return a value to the PL/SQL Block whereas Procedures do not return any value. What are the different types of Exceptions?Ī Cursor is basically used to access values from multiple records in the database or a table. VERIFY Command: Use verify command to confirm the changes in the SQL statement defined with set verify on/off.įEEDBACK Command: Displays the number of records returned by a query.Q3. What is the difference between the “VERIFY” and the “FEEDBACK” command?.The transaction consists of a collection of DML statements that forms a logical unit of work. The exceptions related to PL/SQL cursors are: PL/SQL packages are schema objects that group stored procedures, groups functions, and variables in one place. The database links are read-only to access other information as wellĬonsistency shows that data will not be reflected by other users until the data is committed, so that consistency is maintained. Intersect is the product of two tables and it lists only matching rowsĭatabase links are created in order to form communication between various databases, or different environments like development, test, and production. Can you tell me how many triggers can be applied to a table?Ī maximum of 12 triggers can be applied to one table.It is fixed by using views or temporary tables, so the database selects one and updates the other. It appears when a trigger tries to update a row that is currently using. If a value is an expression is NULL, then the expression itself evaluates to NULL except for concatenation operator.NULL cannot be equal or unequal to other values.What are the rules to be applied to NULLS while doing comparisons?.They are enforced to process each row individually for queries that return multiple rows. The cursor is a named private area in SQL from which information can be accessed. Joins are used to retrieve data from more than one table. What are joins and how many types of joins are there?.It is useful in data warehousing applications. The MERGE statement updates a row in one table, using data from another table. What do you understand by the term called MERGE statement?.It helps the user to develop complex database applications using control procedures, structures, modules etc. It is basically a conduct extension of Oracle- SQL. PL SQL Jobs Interview Questions & Answers: So, before you get more juggled up here we have mentioned below the 15 frequently asked PL SQL interview questions which can help candidates to qualify the interview rounds easily. If you’re the one who is looking for PL SQL Jobs, then preparing well for it is the first task to follow because if you are aware with the basic questions related to the job then clearing every round will be an easy task for you.
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