Explicit Cursor
An explicit cursor names the unnamed work area in which the database stores processing information when it executes a multiple-row query. When you have named the work area, you can access its information, and process the rows of the query individually.
Description of the illustration cursor_declaration.gif
(cursor_parameter_declaration ::=, rowtype ::=)
Description of the illustration cursor_spec.gif
(cursor_parameter_declaration ::=, rowtype ::=)
Description of the illustration cursor_body.gif
cursor_parameter_declaration ::=
Description of the illustration cursor_param_declaration.gif
Description of the illustration rowtype.gif
Keyword and Parameter Descriptions
An explicit cursor previously declared within the current scope.
A type specifier. For the syntax of datatype, see Constant.
A database table or view that must be accessible when the declaration is elaborated.
A combination of variables, constants, literals, operators, and function calls. The simplest expression consists of a single variable. When the declaration is elaborated, the value of expression is assigned to the parameter. The value and the parameter must have compatible data types.
Note:
If you supply an actual parameter forparameter_name when you open the cursor, then expression is not evaluated.A variable declared as the formal parameter of a cursor. A cursor parameter can appear in a query wherever a constant can appear. The formal parameters of a cursor must be IN parameters. The query can also reference other PL/SQL variables within its scope.
A user-defined record previously declared within the current scope.
A user-defined record type that was defined using the data type specifier RECORD.
Specifies the data type of a cursor return value. You can use the %ROWTYPE attribute in the RETURN clause to provide a record type that represents a row in a database table or a row returned by a previously declared cursor. Also, you can use the %TYPE attribute to provide the data type of a previously declared record.
A cursor body must have a SELECT statement and the same RETURN clause as its corresponding cursor specification. Also, the number, order, and data types of select items in the SELECT clause must match the RETURN clause.
A record type that represents a row in a database table or a row fetched from a previously declared cursor or cursor variable. Fields in the record and corresponding columns in the row have the same names and data types.
A SQL SELECT statement. If the cursor declaration declares parameters, each parameter must appear in select_statement.
Provides the data type of a previously declared user-defined record.
You must declare a cursor before referencing it in an OPEN, FETCH, or CLOSE statement.
Note:
An explicit cursor declared in a package specification is affected by theAUTHID clause of the package. For more information, see "CREATE PACKAGE Statement".You must declare a variable before referencing it in a cursor declaration. The word SQL is reserved by PL/SQL as the default name for SQL cursors, and cannot be used in a cursor declaration.
You cannot assign values to a cursor name or use it in an expression. However, cursors and variables follow the same scoping rules. For more information, see Scope and Visibility of PL/SQL Identifiers.
You retrieve data from a cursor by opening it, then fetching from it. Because the FETCH statement specifies the target variables, using an INTO clause in the SELECT statement of a cursor_declaration is redundant and invalid.
The scope of cursor parameters is local to the cursor, meaning that they can be referenced only within the query used in the cursor declaration. The values of cursor parameters are used by the associated query when the cursor is opened. The query can also reference other PL/SQL variables within its scope.
The data type of a cursor parameter must be specified without constraints, that is, without precision and scale for numbers, and without length for strings.