1.Can you have two functions with the same name in a PL/SQL block ?
Answer: Yes.
2. Can you have two stored functions with the same name ?
Answer: Yes.
3. Can you call a stored function in the constraint of a table ?
Answer: No.
4. What are the various types of parameter modes in a procedure ?
Answer: IN, OUT AND INOUT.
5. What is Over Loading and what are its restrictions ?
Answer: OverLoading means an object performing different functions depending upon the no.of parameters or the data type of the parameters passed to it.
6. Can functions be overloaded ?
Answer: Yes.
7. Can 2 functions have same name & input parameters but differ only by return datatype
Answer: No.
8. What are the constructs of a procedure, function or a package ?
Answer: The constructs of a procedure, function or a package are :
- variables and constants
- cursors
- exceptions
9 What are mutating triggers ?
Answer: A trigger giving a SELECT on the table on which the trigger is written.
10 What are constraining triggers ?
Answer: A trigger giving an Insert/Updat e on a table having referential integrity constraint on the triggering table.
11 Describe Oracle database's physical and logical structure ?
Answer:
- Physical : Data files, Redo Log files, Control file.
- Logical : Tables, Views, Tablespaces, etc.
12 Can you increase the size of a tablespace ? How ?
Answer: Yes, by adding datafiles to it.
13 Can you increase the size of datafiles ? How ?
Answer: No (for Oracle 7.0)
Yes (for Oracle 7.3 by using the Resize clause )
Yes (for Oracle 7.3 by using the Resize clause )
14 What is the use of Control files ?
Answer: Contains pointers to locations of various data files, redo log files, etc.
What is the use of Data Dictionary ?
Answer: It Used by Oracle to store information about various physical and logical Oracle structures e.g.Tables, Tablespaces, datafiles, etc
15 What are the advantages of clusters ?
Answer: Access time reduced for joins.
16 What are the disadvantages of clusters ?
Answer: The time for Insert increases.
17 Can Long/Long RAW be clustered ?
Answer: No.
18 Can null keys be entered in cluster index, normal index ?
Answer: Yes.
19 Can Check constraint be used for self referential integrity ? How ?
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.
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20 What are the min.extents allocated to a rollback extent ?
Answer: Two
21 What are the states of a rollback segment ? What is the difference between partly available and needs recovery ?
Answer: The various states of a rollback segment are :
- ONLINE
- OFFLINE
- PARTLY AVAILABLE
- NEEDS RECOVERY
- INVALID.
22 What is the difference between unique key and primary key ?
Answer: Unique key can be null; Primary key cannot be null.
23 An insert statement followed by a create table statement followed by rollback ? Will the rows be inserted ?
Answer: No.
24 Can you define multiple savepoints ?
Answer: Yes.
25 Can you Rollback to any savepoint ?
Answer: Yes.
26 What is the maximum no.of columns a table can have ?
Answer: 254.
27 What is the significance of the & and && operators in PL SQL ?
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 for this same variable
The && operator means that the value of this variable should be the same as inputted by the user previously for this same variable
28 Can you pass a parameter to a cursor ?
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; |
29 What are the various types of RollBack Segments ?
Answer: The types of Rollback sagments are as follows :
- Public Available to all instances
- Private Available to specific instance
30 Can you use %RowCount as a parameter to a cursor ?
Answer: Yes
31 Is the query below allowed :
Select sal, ename Into x From emp Where ename = 'KING' (Where x is a record of Number(4) and Char(15))
Select sal, ename Into x From emp Where ename = 'KING' (Where x is a record of Number(4) and Char(15))
Answer: Yes
32 Is the assignment given below allowed :
ABC = PQR (Where ABC and PQR are records)
ABC = PQR (Where ABC and PQR are records)
Answer: Yes
33 Is this for loop allowed :
For x in &Start..&End Loop
For x in &Start..&End Loop
Answer: Yes
34 How many rows will the following SQL return :
Select * from emp Where rownum < 10;
Select * from emp Where rownum < 10;
Answer: 9 rows
35 How many rows will the following SQL return :
Select * from emp Where rownum = 10;
Select * from emp Where rownum = 10;
Answer: No rows
36 Which symbol preceeds the path to the table in the remote database ?
Answer: @
37 Are views automatically updated when base tables are updated ?
Answer: Yes
38 Can a trigger written for a view ?
Answer: No
39 If all the values from a cursor have been fetched and another fetch is issued, the output will be : error, last record or first record ?
Answer: Last Record
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40 A table has the following data : [[5, Null, 10]].What will the average function return ?
Answer: 7.5
41 Is Sysdate a system variable or a system function?
Answer: System Function
42 Consider a sequence whose currval is 1 and gets incremented by 1 by using the nextval reference we get the next number 2.Suppose at this point we issue an rollback and again issue a nextval.What will the output be ?
Answer: 3
43 Definition of relational DataBase by Dr.Codd (IBM)?
Answer: A Relational Database is a database where all data visible to the user is organized strictly as tables of data values and where all database operations work on these tables.
44 What is Multi Threaded Server (MTA) ?
Answer: In a Single Threaded Architecture (or a dedicated server configuration) the database manager creates a separate process for each database user.But in MTA the database manager can assign multiple users (multiple user processes) to a single dispatcher (server process), a controlling process that queues request for work thus reducing the databases
45 Which are initial RDBMS, Hierarchical & N/w database ?
Answer:
- RDBMS - R system
- Hierarchical - IMS
- N/W - DBTG
46 Difference between Oracle 6 and Oracle 7
Answer:
ORACLE 7
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ORACLE 6
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Cost based optimizer
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Rule based optimizer
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Shared SQL Area
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SQL area allocated for each user
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Multi Threaded Server
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Single Threaded Server
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Hash Clusters
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Only B-Tree indexing
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Roll back Size Adjustment
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No provision
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Truncate command
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No provision
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Distributed Database
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Distributed Query
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Table replication & snapshots
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No provision
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Client/Server Tech
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No provision
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47 What is Functional Dependency
Answer: Given a relation R, attribute Y of R is functionally dependent on attribute X of R if and only if each X-value has associated with it precisely one -Y value in R
48 What is Auditing ?
Answer: The database has the ability to audit all actions that take place within it. a) Login attempts, b) Object Accesss, c) Database Action Result of Greatest(1,NULL) or Least(1,NULL) NULL
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49 While designing in client/server what are the 2 imp.things to be considered ?
Answer: Network Overhead (traffic), Speed and Load of client server
50 What are the disadvantages of SQL ?
Answer: Disadvantages of SQL are :
- Cannot drop a field
- Cannot rename a field
- Cannot manage memory
- Procedural Language option not provided
- Index on view or index on index not provided
- View updation problem
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