Cursor Review

Contact Us or call 1-877-932-8228
Cursor Review

Cursor Review

A cursor is a name attached to a database result set in memory. You might think of it as a pointer or reference to a virtual table containing zero or more rows of data. Because PL/SQL is a language that is used primarily within a database environment, the use of cursors is unavoidable for all but the simplest of tasks. You have already seen cursors introduced in earlier lessons. To review some of the major points:

  • Cursors are explicit if they are specifically declared as such in PL/SQL code. They are implicit when simply used in the background as part of a SELECT INTO or DML statement.
  • The basic pattern for dealing with explicit cursors is to declare the cursor, open it, loop through the rows referenced by the cursor (if necessary), fetch the results into variables and close the cursor.
  • An alternative to this is to use a cursor for loop where a cursor is created on the fly without the need to declare, open or close it.
  • Variables declared with %TYPE anchored declarations are based upon corresponding database fields. Variables declared with %ROWTYPE anchored declarations are based upon entire rows in a table.
  • Cursor attributes (e.g. %NOTFOUND, %FOUND, %ISOPEN, %ROWCOUNT) provide information about the cursor in use.
Next