181
Rule TYPEs

This chapter describes the types used with rules, rule sets, and evaluation contexts.

This chapter contains the following topic:

• Summary of Rule Types

Summary of Rule Types

Table 181-1  Rule Types

Rule types are used with the following Oracle-supplied PL/SQL packages:

• DBMS_RULE
• DBMS_RULE_ADM

You can use the DBMS_RULE_ADM package to create and administer rules, rule sets, and evaluation contexts, and you can use the DBMS_RULE package to evaluate rules.

When you use Streams, rules determine which changes are captured by a capture process, which events are propagated by a propagation, which events are applied by an apply process, and which events are dequeued by a messaging client. The following Streams packages use rules:

• DBMS_APPLY_ADM
• DBMS_CAPTURE_ADM
• DBMS_PROPAGATION_ADM
• DBMS_STREAMS
• DBMS_STREAMS_ADM
• DBMS_STREAMS_AUTH

  See Also: Oracle Streams Concepts and Administration

RE$ATTRIBUTE_VALUE Type

Specifies the value of a variable attribute.

Syntax

TYPE SYS.RE$ATTRIBUTE_VALUE (
   variable_name    VARCHAR2(32), 
   attribute_name   VARCHAR2(4000),
   attribute_value  SYS.AnyData); 

Attributes

Table 181-2 RE$ATTRIBUTE_VALUE Attributes

RE$ATTRIBUTE_VALUE_LIST Type

Identifies a list of attribute values.

Syntax

TYPE SYS.RE$ATTRIBUTE_VALUE_LIST AS VARRAY(1024) OF SYS.RE$ATTRIBUTE_VALUE;

RE$COLUMN_VALUE Type

Specifies the value of a table column.

Syntax

TYPE SYS.RE$COLUMN_VALUE (
   table_alias   VARCHAR2(32), 
   column_name   VARCHAR2(4000),
   column_value  SYS.AnyData); 

Attributes

Table 181-3 RE$COLUMN_VALUE Attributes

RE$COLUMN_VALUE_LIST Type

Identifies a list of column values.

Syntax

TYPE SYS.RE$COLUMN_VALUE_LIST AS VARRAY(1024) OF SYS.RE$COLUMN_VALUE;

RE$NAME_ARRAY Type

Identifies a list of names.

Syntax

TYPE SYS.RE$NAME_ARRAY AS VARRAY(1024) OF VARCHAR2(30);

RE$NV_ARRAY Type

Identifies a list of name-value pairs.

Syntax

TYPE SYS.RE$NV_ARRAY AS VARRAY(1024) OF SYS.RE$NV_NODE;

RE$NV_LIST Type

Identifies an object containing a list of name-value pairs and methods that operate on this list. This object type is used to represent the event context for rule set evaluation and the action context for a rule.

Syntax

TYPE SYS.RE$NV_LIST AS OBJECT( 
   actx_list  SYS.RE$NV_ARRAY);

Attributes

Table 181-4 RE$NV_LIST Attributes

RE$NV_LIST Subprograms

This section describes the following member procedures and member functions of the SYS.RE$NV_LIST type:

• ADD_PAIR Member Procedure
• GET_ALL_NAMES Member Function
• GET_VALUE Member Function
• REMOVE_PAIR Member Procedure

ADD_PAIR Member Procedure

Adds a name-value pair to the list of name-value pairs.

Syntax

MEMBER PROCEDURE ADD_PAIR(
   name   IN  VARCHAR2, 
   value  IN  SYS.AnyData);

Parameters

Table 181-5 ADD_PAIR Procedure Parameters

Parameter	Description
name	The name in the name-value pair being added to the list. If the name already exists in the list, then an error is raised.
value	The value in the name-value pair being added to the list

GET_ALL_NAMES Member Function

Returns a list of all the names in the name-value pair list.

Syntax

MEMBER FUNCTION GET_ALL_NAMES()
RETURN SYS.RE$NAME_ARRAY;

GET_VALUE Member Function

Returns the value for the specified name in a name-value pair list.

Syntax

MEMBER FUNCTION GET_VALUE(
   name  IN  VARCHAR2) 
RETURN SYS.AnyData;

Parameters

Table 181-6 GET_VALUE Procedure Parameters

Parameter	Description
name	The name whose value to return

REMOVE_PAIR Member Procedure

Removes the name-value pair with the specified name from the name-value pair list.

Syntax

MEMBER PROCEDURE REMOVE_PAIR(
   name  IN  VARCHAR2);

Parameters

Table 181-7 REMOVE_PAIR Procedure Parameters

Parameter	Description
name	The name of the pair to remove

RE$NV_NODE Type

Identifies a name-value pair.

Syntax

TYPE SYS.RE$NV_NODE (
   nvn_name   VARCHAR2(30), 
   nvn_value  SYS.AnyData); 

Attributes

Table 181-8 RE$NV_NODE Attributes

RE$RULE_HIT Type

Specifies a rule found as a result of an evaluation.

Syntax

TYPE SYS.RE$RULE_HIT (
   rule_name            VARCHAR2(65),
   rule_action_context  RE$NV_LIST); 

Attributes

Table 181-9 RE$RULE_HIT Attributes

RE$RULE_HIT_LIST Type

Identifies a list of rules found as a result of an evaluation.

Syntax

TYPE SYS.RE$RULE_HIT_LIST AS VARRAY(1024) OF SYS.RE$RULE_HIT;

RE$TABLE_ALIAS Type

Provides the table corresponding to an alias used in a rule evaluation context. A specified table name must satisfy the schema object naming rules.

Syntax

TYPE SYS.RE$TABLE_ALIAS IS OBJECT(
   table_alias  VARCHAR2(32),
   table_name   VARCHAR2(194));

Attributes

Table 181-10 RE$TABLE_ALIAS Attributes

schema_name.table_name

table_name

hr.employees

RE$TABLE_ALIAS_LIST Type

Identifies a list of table aliases used in a rule evaluation context.

Syntax

TYPE SYS.RE$TABLE_ALIAS_LIST AS VARRAY(1024) OF SYS.RE$TABLE_ALIAS;

RE$TABLE_VALUE Type

Specifies the value of a table row using a ROWID.

Syntax

TYPE SYS.RE$TABLE_VALUE(
   table_alias  VARCHAR2(32), 
   table_rowid  VARCHAR2(18));

Attributes

Table 181-11 RE$TABLE_VALUE Attributes

RE$TABLE_VALUE_LIST Type

Identifies a list of table values.

Syntax

TYPE SYS.RE$TABLE_VALUE_LIST AS VARRAY(1024) OF SYS.RE$TABLE_VALUE;

RE$VARIABLE_TYPE Type

Provides the type of a variable used in a rule evaluation context. A specified variable name must satisfy the schema object naming rules.

Syntax

TYPE SYS.RE$VARIABLE_TYPE (
   variable_name             VARCHAR2(32),
   variable_type             VARCHAR2(4000),
   variable_value_function   VARCHAR2(228),
   variable_method_function  VARCHAR2(228));

Attributes

Table 181-12 RE$VARIABLE_TYPE Attributes

Usage Notes

The functions for both the for the variable_value_function parameter and variable_method_function parameter have the following format:

schema_name.package_name.function_name@dblink

Any of the following parts of the format may be omitted: schema_name, package_name, and @dblink.

For example, if the schema_name is hr, the package_name is var_pac, the function_name is func_value, and the dblink is dbs1.net, then enter the following:

hr.var_pac.func_value@dbs1.net

The following sections describe the signature of the functions.

Signature for variable_value_function

The function must have the following signature:

FUNCTION variable_value_function_name(
  evaluation_context_schema  IN VARCHAR2,       
  evaluation_context_name    IN VARCHAR2,
  variable_name              IN VARCHAR2,
  event_context              IN SYS.RE$NV_LIST )
RETURN SYS.RE$VARIABLE_VALUE;

Signature for variable_method_function

This function must have the following signature:

FUNCTION variable_method_function_name(    
  evaluation_context_schema  IN VARCHAR2, 
  evaluation_context_name    IN VARCHAR2, 
  variable_value             IN SYS.RE$VARIABLE_VALUE, 
  method_name                IN VARCHAR2, 
  event_context              IN SYS.RE$NV_LIST)
RETURN SYS.RE$ATTRIBUTE_VALUE;

RE$VARIABLE_TYPE_LIST Type

Identifies a list of variables and their types used in a rule evaluation context.

Syntax

TYPE SYS.RE$VARIABLE_TYPE_LIST AS VARRAY(1024) OF SYS.RE$VARIABLE_TYPE;

RE$VARIABLE_VALUE Type

Specifies the value of a variable.

Syntax

TYPE SYS.RE$VARIABLE_VALUE (
   variable_name  VARCHAR2(32), 
   variable_data  SYS.AnyData); 

Attributes

Table 181-13 RE$VARIABLE_VALUE Attributes

RE$VARIABLE_VALUE_LIST Type

Identifies a list of variable values.

Syntax

TYPE SYS.RE$VARIABLE_VALUE_LIST AS VARRAY(1024) OF SYS.RE$VARIABLE_VALUE;