If there is any type mismatch, variable assignments and comparisons may not work the way you expect.
To be safe, instead of hard coding the type of a variable, you should use the This program has no effect when run, because there are no changes to the database.
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.
A block has the following structure: DECLARE /* Declarative section: variables, types, and local subprograms.
*/ BEGIN /* Executable section: procedural and SQL statements go here.
They must be created when you are executing a SELECT statement that returns more than one row.
basis -- and I want to add my name to the list of people who wish cursors had never been introduced. Problems with cursors include extending locks, their inability to cache execution plans and CPU/RAM overhead.
Many T-SQL programmers and DBAs do not know how to successfully loop over records without the need for cursors.
Oracle9i allows us to use Record structures during bulk operations so long as we don't reference individual columns of the collection.
This restriction means that updates and deletes which have to reference inividual columns of the collection in the where clause are still restricted to the collection-per-column approach used in Oracle8i.