What are cursors? Name four types of cursors and when each
one would be applied?
Answer Posted / khushboo rastogi
A cursor is a temporary work area created in the system memory when a SQL statement
is executed. A cursor contains information on a select statement and the rows of data
accessed by it. This temporary work area is used to store the data retrieved from the
database, and manipulate this data. A cursor can hold more than one row, but can process
only one row at a time. The set of rows the cursor holds is called the active set.
There are two types of cursors in PL/SQL:
Implicit cursors:
These are created by default when DML statements like, INSERT, UPDATE, and
DELETE statements are executed. They are also created when a SELECT statement that
returns just one row is executed.
Explicit cursors:
They must be created when you are executing a SELECT statement that returns more
than one row. Even though the cursor stores multiple records, only one record can be
processed at a time, which is called as current row. When you fetch a row the current row
position moves to next row.
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