Exam 6: The Basics of Querying a Database

User-defined SQL functions are functions in which Java is used to custom write functions for specific tasks,which are not available in functions provided in an Oracle database.

A space character or a 0 value are NULL.

Subqueries can be nested within subqueries.

Composite queries use special set operators,such as UNION,to concatenate the rows of two different queries together,into a single resulting set of rows.

____ validates an expression as being between two values,and is inclusive.

A query using a subquery is also called a(n)____________________ when performing the same or similar function to that of a join.

A(n)____ is a chunk of memory allocated to a query,to contain the results of a query during processing of that query.

The ____ statement or clause is the beginning of the SQL command for querying (retrieving)data from a database object,such as a table or view.

____ queries create groupings or summaries of larger row sets,producing,for example,a sum of values or a number of subtotals from all values.

____ is used to represent one and only one character.

A(n)____________________ view implies a view created inline within a query.

The ____________________ clause has two distinct facets: (1)comparison conditions,and (2)logical operators.

Pseudocolumns contain values present in a table,but not in an Oracle instance.

____ set membership evaluates an expression as being within a set of elements.

Any expression containing a NULL value always returns a NULL value.

Provide an example of a join query.

____ is a wildcard character.

The DUAL table is owned by ____________________ but can be queried by any user.

Flashback queries execute SQL statements in parallel,preferably using multiple CPU platforms and Oracle partitions.

As already seen in this chapter,SELECT statements can be embedded in ____________________ commands as subqueries (within INSERT,UPDATE,and DELETE statements).