61.How many memory layers are in the Oracle shared pool?

Oracle shared pools contains two layers:

62.What is save point in Oracle database?

Save points are used to divide a transaction into smaller parts. It allows rolling back of a transaction. Maximum five save points are allowed. It is used to save our data, whenever you encounter an error you can roll back from the point where you save your SAVEPOINT.

63.What is hash cluster in Oracle?

Hash cluster is a technique to store a data in hash table and improve the performance of data retrieval. Hash function is applied on table row's cluster key value and store in hash cluster.

64.What are the various Oracle database objects?

Tables: This is a set of elements organized in vertical and horizontal fashion.
Tablespaces: This is a logical storage unit in Oracle.
Views: It is virtual table derived from one or more tables.
Indexes: This is a performance tuning method to process the records.
Synonyms: This is a name for tables.

65.What is the difference between pre-select and pre-query?

A pre-query trigger fire before the query executes and fire once while you try to query. With the help of this trigger you can modify the where clause part dynamically.
Pre-select query fires during the execute query and count query processing after Oracle forms construct the select statement to be issued, but before the statement is actually issued.
Pre-query trigger fires before Pre-select trigger.

66.How to convert a date to char in Oracle? Give one example.

The to_char() function is used to convert date to character. You can also specify the format in which you want output.

67.What are the extensions used by Oracle reports?

Oracle reports are use to make business enable with the facility to provide information of all level within or outside in a secure way. Oracle report uses

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