SQL / PL SQL Questions

How do you convert a date to a string?
What is an aggregate function?
What is the dual table?
What are cursors? Distinguish between implicit and explict cursors?
Explain how cursors are used by Oracle?
What is PL/SQL? Describe the block structure of PL/SQL?
What is a nested subquery?
What are the various types of queries ?
Which of the following is not a schema object : Index, table, public synonym, trigger and package ?
What is dynamic sql in oracle?
What is the difference between a package, procedure and function
What is the difference between delete, drop and truncating a table
How many triggers are supported in Oracle
Are you aware of FLASHBACK concept ? What is it?
Describe oracle’s logical and physical structure?
What is data dictionary
What is the use of control files
How would store XML data in table ? What data type would be used for the columns?
Difference between post and commit?
Difference between commit and rollback?
What are savepoints?
Difference between a View and Synonym
How would you fetch system date from oracle
What is the difference between primary key, unique key, foreign key?
What is the difference between NO DATA FOUND and %NOTFOUND
What is cursor for loop
What are cursor attributes
What will you use in Query : IN or EXISTS? Why
Explain the difference between a data block, an extent and a segment.
What's the difference between logical and physical I/O?
What is an anonymous block?
What is a PL/SQL collection?
How can you tell if an UPDATE updated no rows
How can you tell if a SELECT returned no rows

DB concepts:

Physical Database Structure

1. Datafiles
2. Redo log files
3. Control files.

Logical Structures

1. TableSpaces
2. DB Schema Objects.

Segments,Extents and Data Blocks

Oracle background processes


A synonym is an alias for a table, view, sequence, create public synonyms that make the base schema object available for general, system-wide use by any database user.

Indexes are created to increase the performance of data retrieval