Description : What is the difference between unique key and primary key ?
Last Answer : Unique key can be null; Primary key cannot be null.
Description : What are the Referential actions supported by FOREIGN KEY integrity constraint?
Last Answer : UPDATE and DELETE Restrict – A referential integrity rule that disallows the update or deletion of referenced data. DELETE Cascade – When a referenced row is deleted all associated dependent rows are deleted.
Description : Can Check constraint be used for self referential integrity ? How ?
Last Answer : ? Yes. In the CHECK condition for a column of a table, we can reference some other column of the same table and thus enforce self referential integrity.
Description : Can you call a stored function in the constraint of a table ?
Last Answer : no
Description : Write any one similarity and one difference between primary key and unique Constraint. -Technology
Last Answer : Similarity: Column with both the constraints will only take unique values.Difference: Column with Primary key constraints will not be able to hold NULL values while Column with Unique constraints will be able to hold NULL values.
Description : Write any one similarity and one difference between primary key and unique Constraint -Technology
Description : What is difference between UNIQUE constraint and PRIMARY KEY constraint ?
Last Answer : A column defined as UNIQUE can contain Nulls while a column defined as PRIMARY KEY can't contain Nulls.
Description : If an unique key constraint on DATE column is created, will it validate the rows that are inserted with SYSDATE ?
Last Answer : It won't, Because SYSDATE format contains time attached with it.
Description : What are the states of a rollback segment ? What is the difference between partly available and needs recovery ?
Last Answer : The various states of a rollback segment are : ONLINE, OFFLINE, PARTLY AVAILABLE, NEEDS RECOVERY and INVALID.
Description : What is the difference between a procedure and a function ?
Last Answer : Functions return a single variable by value whereas procedures do not return any variable by value. Rather they return multiple variables by passing variables by reference through their OUT parameter
Description : What is the Difference between a post query and a pre query?
Last Answer : A post query will fire for every row that is fetched but the pre query will fire only once.
Description : What is the difference between deleting and truncating of tables?
Last Answer : Deleting a table will not remove the rows from the table but entry is there in the database dictionary and it can be retrieved But truncating a table deletes it completely and it cannot be retrieved.
Description : Drop Table cannot be used to drop a table referenced by a …………… constraint. A) Local Key B) Primary Key C) Composite Key D) Foreign Key
Last Answer : D) Foreign Key
Description : Drop Table cannot be used to drop a Table referenced by .................. constraint. (a) Primary key (b) Sub key (c) Super key (d) Foreign key (A) (a) (B) (a), (b) and (c) (C) (d) (D) (a) and (d)
Last Answer : (C) (d)
Description : How many rows will the following SQL return
Last Answer : Select * from emp Where rownum < 10; 9 rows.
Description : Can you use %RowCount as a parameter to a cursor
Last Answer : Yes
Description : What are the various types of RollBack Segments ?
Last Answer : Public Available to all instances Private Available to specific instance
Description : Can you pass a parameter to a cursor ?
Last Answer : Explicit cursors can take parameters, as the example below shows. A cursor parameter can appear in a query wherever a constant can appear. CURSOR c1 (median IN NUMBER) IS SELECT job, ename FROM emp WHERE sal > median
Description : What is the significance of the & and && operators in PL SQL ?
Last Answer : The & operator means that the PL SQL block requires user input for a variable. The && operator means that the value of this variable should be the same as inputted by the user previously ... span across different rollback segments or will it terminate ? It will terminate (Please check ).
Description : What is the maximum no. of columns a table can have ?
Last Answer : 254.
Description : Can you Rollback to any savepoint ?
Last Answer : Yes.
Description : Can you define multiple savepoints ?
Description : An insert statement followed by a create table statement followed by rollback ? Will the rows be inserted ?
Last Answer : No.
Description : What are the min. extents allocated to a rollback extent ?
Last Answer : Two
Description : Can null keys be entered in cluster index, normal index ?
Description : Can Long/Long RAW be clustered ?
Description : What are the disadvantages of clusters ?
Last Answer : The time for Insert increases.
Description : What are the advantages of clusters ?
Last Answer : Access time reduced for joins.
Description : What is the use of Data Dictionary ?
Last Answer : Used by Oracle to store information about various physical and logical Oracle structures e.g. Tables, Tablespaces, datafiles, et
Description : What is the use of Control files ?
Last Answer : Contains pointers to locations of various data files, redo log files, etc.
Description : Can you increase the size of datafiles ? How ?
Last Answer : No (for Oracle 7.0)
Description : Can you increase the size of a tablespace ? How ?
Last Answer : Yes, by adding datafiles to it.
Description : Describe Oracle database's physical and logical structure
Last Answer : Physical : Data files, Redo Log files, Control file. Logical : Tables, Views, Tablespaces, etc.
Description : What are constraining triggers ?
Last Answer : A trigger giving an Insert/Updat e on a table having referential integrity constraint on the triggering table.
Description : What are mutating triggers ?
Last Answer : A trigger giving a SELECT on the table on which the trigger is written.
Description : What are cascading triggers? What is the maximum no of cascading triggers at a time?
Last Answer : When a statement in a trigger body causes another trigger to be fired, the triggers are said to be cascading. Max = 32.
Description : Can views be specified in a trigger statement ?
Last Answer : No
Description : What is the maximum no. of statements that can be specified in a trigger statement?
Last Answer : One.
Description : What is the advantage of a stored procedure over a database trigger ?
Last Answer : We have control over the firing of a stored procedure but we have no control over the firing of a trigger.
Description : What are the various types of database triggers ?
Last Answer : There are 12 types of triggers, they are combination of : Insert, Delete and Update Triggers. Before and After Triggers. Row and Statement Triggers. (3*2*2=12)
Description : What are the parts of a database trigger ?
Last Answer : The parts of a trigger are: A triggering event or statement A trigger restriction A trigger action
Description : Can you pass parameters in packages ? How ?
Last Answer : Yes. You can pass parameters to procedures or functions in a package.
Description : Why Create or Replace and not Drop and recreate procedures ?
Last Answer : So that Grants are not dropped.
Description : What are the constructs of a procedure, function or a package ?
Last Answer : The constructs of a procedure, function or a package are : variables and constants cursors exceptions
Description : Can 2 functions have same name & input parameters but differ only by return datatype
Description : Can functions be overloaded ?
Description : What is Over Loading and what are its restrictions ?
Last Answer : OverLoading means an object performing different functions depending upon the no. of parameters or the data type of the parameters passed to it.
Description : What are the various types of parameter modes in a procedure ?
Last Answer : IN, OUT AND INOUT.
Description : Can you have two stored functions with the same name ?
Description : Can you have two functions with the same name in a PL/SQL block