257 Rule TYPEs

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

This chapter contains the following topics:

Using Rule Types

This section contains topics that relate to using the types used with rules, rule sets, and evaluation contexts.

Overview

This types in this chapter are used in rules and enable clients to evaluate rules with the rules engine.

See Also:

Security Model

PUBLIC is granted EXECUTE privilege on the types described in this chapter.

See Also:

Oracle Database Security Guide for more information about user group PUBLIC

Summary of Rule Types

Table 257-1 Rule Types

Type Description

RE$ATTRIBUTE_VALUE Type

Specifies the value of a variable attribute

RE$ATTRIBUTE_VALUE_LIST Type

Identifies a list of attribute values

RE$COLUMN_VALUE Type

Specifies the value of a table column

RE$COLUMN_VALUE_LIST Type

Identifies a list of column values

RE$NAME_ARRAY Type

Identifies a list of names

RE$NAME_ARRAY Type

Identifies a list of name-value pairs

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 and the action context for a rule

RE$NV_NODE Type

Identifies a name-value pair

RE$RULE_HIT Type

Specifies a rule found because of evaluation

RE$RULE_HIT_LIST Type

Identifies a list of rules found because of evaluation

RE$TABLE_ALIAS Type

Provides the table corresponding to an alias used in a rule evaluation context

RE$TABLE_ALIAS_LIST Type

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

RE$TABLE_VALUE Type

Specifies the value of a table row using a ROWID

RE$TABLE_VALUE_LIST Type

Identifies a list of table values

RE$VARIABLE_TYPE Type

Provides the type of a variable used in a rule evaluation context

RE$VARIABLE_TYPE_LIST Type

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

RE$VARIABLE_VALUE Type

Specifies the value of a variable

RE$VARIABLE_VALUE_LIST Type

Identifies a list of variable values

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

RE$ATTRIBUTE_VALUE Type

Specifies the value of a variable attribute.

Note:

Enclose the variable name and attribute name in double quotation marks (") if the name contains special characters.

Syntax

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

Attributes

Table 257-2 RE$ATTRIBUTE_VALUE Attributes

Attribute Description

variable_name

Specifies the variable used in a rule

attribute_name

Specifies the attribute name. The attribute name can be a multi-component name, such as a1.b2.c3.

attribute_value

Specifies the attribute value

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.

Note:

Enclose the column name in double quotation marks (") if the name contains special characters.

Syntax

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

Attributes

Table 257-3 RE$COLUMN_VALUE Attributes

Attribute Description

table_alias

Specifies the alias used for the table in a rule

column_name

Specifies the column name

column_value

Specifies the column value

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 257-4 RE$NV_LIST Attributes

Attribute Description

actx_list

The list of name-value pairs

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

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

Note:

Enclose the name in double quotation marks (") if the name contains special characters.

Syntax

MEMBER PROCEDURE ADD_PAIR(
   name   IN  VARCHAR2, 
   value  IN  ANYDATA);

Parameters

Table 257-5 ADD_PAIR Procedure Parameters

Parameter Description

name

The name in the name-value pair being added to the list. If the name exists in the list, then this procedure raises an error.

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.

Note:

Enclose the name in double quotation marks (") if the name contains special characters.

Syntax

MEMBER FUNCTION GET_VALUE(
   name  IN  VARCHAR2) 
RETURN ANYDATA;

Parameters

Table 257-6 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.

Note:

Enclose the name in double quotation marks (") if the name contains special characters.

Syntax

MEMBER PROCEDURE REMOVE_PAIR(
   name  IN  VARCHAR2);

Parameters

Table 257-7 REMOVE_PAIR Procedure Parameters

Parameter Description

name

The name of the pair to remove

RE$NV_NODE Type

Identifies a name-value pair.

Note:

Enclose the name in double quotation marks (") if the name contains special characters.

Syntax

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

Attributes

Table 257-8 RE$NV_NODE Attributes

Attribute Description

nvn_name

Specifies the name in the name-value pair

nvn_value

Specifies the value in the name-value pair

RE$RULE_HIT Type

Specifies a rule found because of an evaluation.

See Also:

Syntax

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

Attributes

Table 257-9 RE$RULE_HIT Attributes

Attribute Description

rule_name

The rule name in the form schema_name.rule_name. For example, a rule named employee_rule in the hr schema is returned in the form "hr"."employee_rule".

rule_action_context

The rule action context as specified in the CREATE_RULE or ALTER_RULE procedure of the DBMS_RULE_ADM package

RE$RULE_HIT_LIST Type

Identifies a list of rules found because 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.

Note:

Enclose the table name in double quotation marks (") if the name contains special characters.

See Also:

Oracle Database SQL Language Reference for information about schema object naming rules

Syntax

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

Attributes

Table 257-10 RE$TABLE_ALIAS Attributes

Attribute Description

table_alias

The alias used for the table in a rule

table_name

The table name referred to by the alias. A synonym can be specified. The table name is resolved in the evaluation context schema.

The format is one of the following:

schema_name.table_name

table_name

For example, if the schema_name is hr and the table_name is employees, then enter the following:

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 257-11 RE$TABLE_VALUE Attributes

Attribute Description

table_alias

Specifies the alias used for the table in a rule

table_rowid

Specifies the rowid for the table row

RE$TABLE_VALUE_LIST Type

Identifies a list of table values.

Note:

Each table alias in the list in the list must be unique.

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.

Note:

Enclose the variable name in double quotation marks (") if the name contains special characters.

See Also:

Oracle Database SQL Language Reference for information about 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 257-12 RE$VARIABLE_TYPE Attributes

Attribute Description

variable_name

The variable name used in a rule

variable_type

The type that is resolved in the evaluation context schema. Any valid Oracle built-in data type, user-defined type, or Oracle-supplied type can be specified. See the Oracle Database SQL Language Reference for more information about these types.

variable_value_function

A value function that can be specified for implicit variables. A synonym can be specified. The function name is resolved in the evaluation context schema. It is executed on behalf of the owner of a rule set using the evaluation context or containing a rule that uses the evaluation context.

See the "Usage Notes" for more information.

variable_method_function

Specifies a value function, which can return the result of a method invocation. Specifying such a function can speed up evaluation, if there are many simple rules that invoke the method on the variable. The function can be a synonym or a remote function.

The function name is resolved in the evaluation context schema. It is executed on behalf of the owner of a rule set using the evaluation context or containing a rule that uses the evaluation context.

See the "Usage Notes" for more information.

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 can 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.

Note:

Enclose the variable name in double quotation marks (") if the name contains special characters.

Syntax

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

Attributes

Table 257-13 RE$VARIABLE_VALUE Attributes

Attribute Description

variable_name

Specifies the variable name used in a rule

variable_data

Specifies the data for the variable value

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;