This chapter explains the concepts related to rules.
This chapter contains these topics:
See Also:
A rule is a database object that enables a client to perform an action when an event occurs and a condition is satisfied. A rule consists of the following components:
Rule Evaluation Context (optional)
Rule Action Context (optional)
Each rule is specified as a condition that is similar to the condition in the WHERE
clause of a SQL query. You can group related rules together into rule sets. A single rule can be in one rule set, multiple rule sets, or no rule sets.
Rule sets are evaluated by a rules engine, which is a built-in part of Oracle. Both user-created applications and Oracle features, such as Streams, can be clients of the rules engine.
Note:
A rule must be in a rule set for it to be evaluated.A rule condition combines one or more expressions and conditions and returns a Boolean value, which is a value of TRUE
, FALSE
, or NULL
(unknown). An expression is a combination of one or more values and operators that evaluate to a value. A value can be data in a table, data in variables, or data returned by a SQL function or a PL/SQL function. For example, the following expression includes only a single value:
salary
The following expression includes two values (salary
and .1
) and an operator (*
):
salary * .1
The following condition consists of two expressions (salary
and 3800
) and a condition (=
):
salary = 3800
This logical condition evaluates to TRUE
for a given row when the salary
column is 3800
. Here, the value is data in the salary
column of a table.
A single rule condition can include more than one condition combined with the AND
, OR
, and NOT
logical conditions to a form compound condition. A logical condition combines the results of two component conditions to produce a single result based on them or to invert the result of a single condition. For example, consider the following compound condition:
salary = 3800 OR job_title = 'Programmer'
This rule condition contains two conditions joined by the OR
logical condition. If either condition evaluates to TRUE
, then the rule condition evaluates to TRUE
. If the logical condition were AND
instead of OR
, then both conditions must evaluate to TRUE
for the entire rule condition to evaluate to TRUE
.
Rule conditions can contain variables. When you use variables in rule conditions, precede each variable with a colon (:). The following is an example of a variable used in a rule condition:
:x = 55
Variables let you refer to data that is not stored in a table. A variable can also improve performance by replacing a commonly occurring expression. Performance can improve because, instead of evaluating the same expression multiple times, the variable is evaluated once.
A rule condition can also contain an evaluation of a call to a subprogram. Such a condition is evaluated in the same way as other conditions. That is, it evaluates to a value of TRUE
, FALSE
, or NULL
(unknown). The following is an example of a condition that contains a call to a simple function named is_manager
that determines whether an employee is a manager:
is_manager(employee_id) = 'Y'
Here, the value of employee_id
is determined by data in a table where employee_id
is a column.
You can use user-defined types for variables. Therefore, variables can have attributes. When a variable has attributes, each attribute contains partial data for the variable. In rule conditions, you specify attributes using dot notation. For example, the following condition evaluates to TRUE
if the value of attribute z
in variable y
is 9
:
:y.z = 9
Note:
A rule cannot have aNULL
(or empty) rule condition.See Also:
Oracle Database SQL Reference for more information about conditions, expressions, and operators
Oracle Database Application Developer's Guide - Object-Relational Features for more information about user-defined types
A simple rule condition is a condition that has one of the following forms:
simple_rule_expression condition constant
constant condition simple_rule_expression
constant condition constant
In a simple rule condition, a simple_rule_expression
is one of the following:
Table column.
Variable.
Variable attribute.
Method result where the method either takes no arguments or constant arguments and the method result can be returned by the variable method function, so that the expression is one of the datatypes supported for simple rules. Such methods include LCR member subprograms that meet these requirements, such as GET_TAG
, GET_VALUE
, GET_COMPATIBLE
, GET_EXTRA_ATTRIBUTE
, and so on.
For table columns, variables, variable attributes, and method results, the following datatypes can be used in simple rule conditions:
VARCHAR2
NVARCHAR2
NUMBER
DATE
BINARY_FLOAT
BINARY_DOUBLE
TIMESTAMP
TIMESTAMP
WITH
TIME
ZONE
TIMESTAMP
WITH
LOCAL
TIME
ZONE
RAW
CHAR
Use of other datatypes in expressions results in nonsimple rule conditions.
In a simple rule condition, a condition
is one of the following:
<=
<
=
>
>=
!=
IS NULL
IS NOT NULL
Use of other conditions results in nonsimple rule conditions.
A constant
is a fixed value. A constant can be:
A number, such as 12
or 5.4
A character, such as x
or $
A character string, such as "this
is
a
string"
The following conditions are simple rule conditions, assuming the datatypes used in expressions are supported in simple rule conditions:
tab1.col = 5
tab2.col != 5
:v1 > 'aaa'
:v2.a1 < 10.01
:v3.m() = 10
:v4 IS NOT NULL
1 = 1
'abc' > 'AB'
:date_var < to_date('04-01-2004, 14:20:17', 'mm-dd-yyyy, hh24:mi:ss')
:adt_var.ts_attribute >= to_timestamp('04-01-2004, 14:20:17 PST', 'mm-dd-yyyy, hh24:mi:ss TZR')
:my_var.my_to_upper('abc') = 'ABC'
Rules with simple rule conditions are called simple rules. You can combine two or more simple conditions with the logical conditions AND
and OR
for a rule, and the rule remains simple. For example, rules with the following conditions are simple rules:
tab1.col = 5 AND :v1 > 'aaa'
tab1.col = 5 OR :v1 > 'aaa'
However, using the NOT
logical condition in a rule condition causes the rule to be nonsimple.
Simple rules are important for the following reasons:
Simple rules are indexed by the rules engine internally.
Simple rules can be evaluated without executing SQL.
Simple rules can be evaluated with partial data.
When a client uses the DBMS_RULE.EVALUATE
procedure to evaluate an event, the client can specify that only simple rules should be evaluated by specifying true
for the simple_rules_only
parameter.
See Also:
Oracle Database SQL Reference for more information about conditions and logical conditions
Oracle Database PL/SQL Packages and Types Reference for more information about LCR types and their member subprograms
An evaluation context is a database object that defines external data that can be referenced in rule conditions. The external data can exist as variables, table data, or both. The following analogy might be helpful: If the rule condition were the WHERE
clause in a SQL query, then the external data in the evaluation context would be the tables and bind variables referenced in the FROM
clause of the query. That is, the expressions in the rule condition should reference the tables, table aliases, and variables in the evaluation context to make a valid WHERE
clause.
A rule evaluation context provides the necessary information for interpreting and evaluating the rule conditions that reference external data. For example, if a rule refers to a variable, then the information in the rule evaluation context must contain the variable type. Or, if a rule refers to a table alias, then the information in the evaluation context must define the table alias.
The objects referenced by a rule are determined by the rule evaluation context associated with it. The rule owner must have the necessary privileges to access these objects, such as SELECT
privilege on tables, EXECUTE
privilege on types, and so on. The rule condition is resolved in the schema that owns the evaluation context.
For example, consider a rule evaluation context named hr_evaluation_context
that contains the following information:
Table alias dep
corresponds to the hr.departments
table.
Variables loc_id1
and loc_id2
are both of type NUMBER
.
The hr_evaluation_context
rule evaluation context provides the necessary information for evaluating the following rule condition:
dep.location_id IN (:loc_id1, :loc_id2)
In this case, the rule condition evaluates to TRUE
for a row in the hr.departments
table if that row has a value in the location_id
column that corresponds to either of the values passed in by the loc_id1
or loc_id2
variables. The rule cannot be interpreted or evaluated properly without the information in the hr_evaluation_context
rule evaluation context. Also, notice that dot notation is used to specify the column location_id
in the dep
table alias.
Note:
Views are not supported as base tables in evaluation contexts.The value of a variable referenced in a rule condition can be explicitly specified when the rule is evaluated, or the value of a variable can be implicitly available given the event.
Explicit variables are supplied by the caller at evaluation time. These values are specified by the variable_values
parameter when the DBMS_RULE.EVALUATE
procedure is run.
Implicit variables are not given a value supplied by the caller at evaluation time. The value of an implicit variable is obtained by calling the variable value function. You define this function when you specify the variable_types
list during the creation of an evaluation context using the CREATE_EVALUATION_CONTEXT
procedure in the DBMS_RULE_ADM
package. If the value for an implicit variable is specified during evaluation, then the specified value overrides the value returned by the variable value function.
Specifically, the variable_types
list is of type SYS.RE$VARIABLE_TYPE_LIST
, which is a list of variables of type SYS.RE$VARIABLE_TYPE
. Within each instance of SYS.RE$VARIABLE_TYPE
in the list, the function used to determine the value of an implicit variable is specified as the variable_value_function
attribute.
Whether variables are explicit or implicit is the choice of the designer of the application using the rules engine. The following are reasons for using an implicit variable:
The caller of the DBMS_RULE.EVALUATE
procedure does not need to know anything about the variable, which can reduce the complexity of the application using the rules engine. For example, a variable can call a function that returns a value based on the data being evaluated.
The caller might not have EXECUTE
privileges on the variable value function.
The caller of the DBMS_RULE.EVALUATE
procedure does not know the variable value based on the event, which can improve security if the variable value contains confidential information.
The variable will be used infrequently, and the variable's value always can be derived if necessary. Making such variables implicit means that the caller of the DBMS_RULE.EVALUATE
procedure does not need to specify many uncommon variables.
For example, in the following rule condition, the values of variable x
and variable y
could be specified explicitly, but the value of the variable max
could be returned by running the max
function:
:x = 4 AND :y < :max
Alternatively, variable x
and y
could be implicit variables, and variable max
could be an explicit variable. So, there is no syntactic difference between explicit and implicit variables in the rule condition. You can determine whether a variable is explicit or implicit by querying the DBA_EVALUATION_CONTEXT_VARS
data dictionary view. For explicit variables, the VARIABLE_VALUE_FUNCTION
field is NULL
. For implicit variables, this field contains the name of the function called by the implicit variable.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about the DBMS_RULE
and DBMS_RULE_ADM
packages, and for more information about the Oracle-supplied rule types
Oracle Database Reference for more information about the DBA_EVALUATION_CONTEXT_VARS
data dictionary view
To be evaluated, each rule must be associated with an evaluation context or must be part of a rule set that is associated with an evaluation context. A single evaluation context can be associated with multiple rules or rule sets. The following list describes which evaluation context is used when a rule is evaluated:
If an evaluation context is associated with a rule, then it is used for the rule whenever the rule is evaluated, and any evaluation context associated with the rule set being evaluated is ignored.
If a rule does not have an evaluation context, but an evaluation context was specified for the rule when it was added to a rule set using the ADD_RULE
procedure in the DBMS_RULE_ADM
package, then the evaluation context specified in the ADD_RULE
procedure is used for the rule when the rule set is evaluated.
If no rule evaluation context is associated with a rule and none was specified by the ADD_RULE
procedure, then the evaluation context of the rule set is used for the rule when the rule set is evaluated.
Note:
If a rule does not have an evaluation context, and you try to add it to a rule set that does not have an evaluation context, then an error is raised, unless you specify an evaluation context when you run theADD_RULE
procedure.You have the option of creating an evaluation function to be run with a rule evaluation context. You can use an evaluation function for the following reasons:
You want to bypass the rules engine and instead evaluate events using the evaluation function.
You want to filter events so that some events are evaluated by the evaluation function and other events are evaluated by the rules engine.
You associate a function with a rule evaluation context by specifying the function name for the evaluation_function
parameter when you create the rule evaluation context with the CREATE_EVALUATION_CONTEXT
procedure in the DBMS_RULE_ADM
package. The rules engine invokes the evaluation function during the evaluation of any rule set that uses the evaluation context.
The DBMS_RULE.EVALUATE
procedure is overloaded. The function must have each parameter in one of the DBMS_RULE.EVALUATE
procedures, and the type of each parameter must be same as the type of the corresponding parameter in the DBMS_RULE.EVALUATE
procedure, but the names of the parameters can be different.
An evaluation function has the following return values:
DBMS_RULE_ADM.EVALUATION_SUCCESS
: The user specified evaluation function completed the rule set evaluation successfully. The rules engine returns the results of the evaluation obtained by the evaluation function to the rules engine client using the DBMS_RULE.EVALUATE
procedure.
DBMS_RULE_ADM.EVALUATION_CONTINUE
: The rules engine evaluates the rule set as if there were no evaluation function. The evaluation function is not used, and any results returned by the evaluation function are ignored.
DBMS_RULE_ADM.EVALUATION_FAILURE
: The user-specified evaluation function failed. Rule set evaluation stops, and an error is raised.
If you always want to bypass the rules engine, then the evaluation function should return either EVALUATION_SUCCESS
or EVALUATION_FAILURE
. However, if you want to filter events so that some events are evaluated by the evaluation function and other events are evaluated by the rules engine, then the evaluation function can return all three return values, and it returns EVALUATION_CONTINUE
when the rules engine should be used for evaluation.
If you specify an evaluation function for an evaluation context, then the evaluation function is run during evaluation when the evaluation context is used by a rule set or rule.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about the evaluation function specified in theDBMS_RULE_ADM.CREATE_EVALUATION_CONTEXT
procedure and for more information about the overloaded DBMS_RULE.EVALUATE
procedureAn action context contains optional information associated with a rule that is interpreted by the client of the rules engine when the rule is evaluated for an event. The client of the rules engine can be a user-created application or an internal feature of Oracle, such as Streams. Each rule has only one action context. The information in an action context is of type SYS.RE$NV_LIST
, which is a type that contains an array of name-value pairs.
The rule action context information provides a context for the action taken by a client of the rules engine when a rule evaluates to TRUE
or MAYBE
. The rules engine does not interpret the action context. Instead, it returns the action context, and a client of the rules engine can interpret the action context information.
For example, suppose an event is defined as the addition of a new employee to a company. If the employee information is stored in the hr.employees
table, then the event occurs whenever a row is inserted into this table. The company wants to specify that a number of actions are taken when a new employee is added, but the actions depend on which department the employee joins. One of these actions is that the employee is registered for a course relating to the department.
In this scenario, the company can create a rule for each department with an appropriate action context. Here, an action context returned when a rule evaluates to TRUE
specifies the number of a course that an employee should take. Here are parts of the rule conditions and the action contexts for three departments:
Rule Name | Part of the Rule Condition | Action Context Name-Value Pair |
---|---|---|
rule_dep_10 |
department_id = 10 |
course_number , 1057 |
rule_dep_20 |
department_id = 20 |
course_number , 1215 |
rule_dep_30 |
department_id = 30 |
NULL |
These action contexts return the following instructions to the client application:
The action context for the rule_dep_10
rule instructs the client application to enroll the new employee in course number 1057
.
The action context for the rule_dep_20
rule instructs the client application to enroll the new employee in course number 1215
.
The NULL
action context for the rule_dep_30
rule instructs the client application not to enroll the new employee in any course.
Each action context can contain zero or more name-value pairs. If an action context contains more than one name-value pair, then each name in the list must be unique. In this example, the client application to which the rules engine returns the action context registers the new employee in the course with the returned course number. The client application does not register the employee for a course if a NULL
action context is returned or if the action context does not contain a course number.
If multiple clients use the same rule, or if you want an action context to return more than one name-value pair, then you can list more than one name-value pair in an action context. For example, suppose the company also adds a new employee to a department electronic mailing list. In this case, the action context for the rule_dep_10
rule might contain two name-value pairs:
Name | Value |
---|---|
course_number |
1057 |
dist_list |
admin_list |
The following are considerations for names in name-value pairs:
If different applications use the same action context, then use different names or prefixes of names to avoid naming conflicts.
Do not use $ and # in names because they can cause conflicts with Oracle-supplied action context names.
You add a name-value pair to an action context using the ADD_PAIR
member procedure of the RE$NV_LIST
type. You remove a name-value pair from an action context using the REMOVE_PAIR
member procedure of the RE$NV_LIST
type. If you want to modify an existing name-value pair in an action context, then you should first remove it using the REMOVE_PAIR
member procedure and then add an appropriate name-value pair using the ADD_PAIR
member procedure.
An action context cannot contain information of the following datatypes:
CLOB
NCLOB
BLOB
LONG
LONG
RAW
In addition, an action context cannot contain object types with attributes of these datatypes, or object types that use type evolution or type inheritance.
Note:
Streams uses action contexts for custom rule-based transformations and, when subset rules are specified, for internal transformations that might be required on LCRs containingUPDATE
operations. Streams also uses action contexts to specify a destination queue into which an apply process enqueues messages that satisfy the rule. In addition, Streams uses action contexts to specify whether or not a message that satisfies an apply process rule is executed by the apply process.See Also:
"Creating a Rule with an Action Context" and "Altering a Rule" for examples that add and modify name-value pairs
Oracle Database PL/SQL Packages and Types Reference for more information about the RE$NV_LIST
type
The rules engine evaluates rule sets against an event. An event is an occurrence that is defined by the client of the rules engine. The client initiates evaluation of an event by calling the DBMS_RULE.EVALUATE
procedure. This procedure enables the client to send some information about the event to the rules engine for evaluation against a rule set. The event itself can have more information than the information that the client sends to the rules engine.
The following information is specified by the client when it calls the DBMS_RULE.EVALUATE
procedure:
The name of the rule set that contains the rules to use to evaluate the event.
The evaluation context to use for evaluation. Only rules that use the specified evaluation context are evaluated.
Table values and variable values. The table values contain rowids that refer to the data in table rows, and the variable values contain the data for explicit variables. Values specified for implicit variables override the values that might be obtained using a variable value function. If a specified variable has attributes, then the client can send a value for the entire variable, or the client can send values for any number of the attributes of the variable. However, clients cannot specify attribute values if the value of the entire variable is specified.
An optional event context. An event context is a varray of type SYS.RE$NV_LIST
that contains name-value pairs that contain information about the event. This optional information is not used directly or interpreted by the rules engine. Instead, it is passed to client callbacks, such as an evaluation function, a variable value function (for implicit variables), and a variable method function.
The client can also send other information about how to evaluate an event against the rule set using the DBMS_RULE.EVALUATE
procedure. For example, the caller can specify if evaluation must stop as soon as the first TRUE
rule or the first MAYBE
rule (if there are no TRUE
rules) is found.
If the client wants all of the rules that evaluate to TRUE
or MAYBE
returned to it, then the client can specify whether evaluation results should be sent back in a complete list of the rules that evaluated to TRUE
or MAYBE
, or evaluation results should be sent back iteratively. When evaluation results are sent iteratively to the client, the client can retrieve each rule that evaluated to TRUE
or MAYBE
one by one using the GET_NEXT_HIT
function in the DBMS_RULE
package.
The rules engine uses the rules in the specified rule set for evaluation and returns the results to the client. The rules engine returns rules using two OUT
parameters in the EVALUATE
procedure. This procedure is overloaded and the two OUT
parameters are different in each version of the procedure:
One version of the procedure returns all of the rules that evaluate to TRUE
in one list or all of the rules that evaluate to MAYBE
in one list, and the two OUT
parameters for this version of the procedure are true_rules
and maybe_rules
. That is, the true_rules
parameter returns rules in one list that evaluate to TRUE
, and the maybe_rules
parameter returns rules in one list that might evaluate to TRUE
given more information.
The other version of the procedure returns all of the rules that evaluate to TRUE
or MAYBE
iteratively at the request of the client, and the two OUT
parameters for this version of the procedure are true_rules_iterator
and maybe_rules_iterator
. That is, the true_rules_iterator
parameter returns rules that evaluate to TRUE
one by one, and the maybe_rules_iterator
parameter returns rules one by one that might evaluate to TRUE
given more information.
Figure 5-1 shows the rule set evaluation process:
A client-defined event occurs.
The client initiates evaluation of a rule set by sending information about an event to the rules engine using the DBMS_RULE.EVALUATE
procedure.
The rules engine evaluates the rule set for the event using the relevant evaluation context. The client specifies both the rule set and the evaluation context in the call to the DBMS_RULE.EVALUATE
procedure. Only rules that are in the specified rule set, and use the specified evaluation context, are used for evaluation.
The rules engine obtains the results of the evaluation. Each rule evaluates to either TRUE
, FALSE
, or NULL
(unknown).
The rules engine returns rules that evaluated to TRUE
to the client, either in a complete list or one by one. Each returned rule is returned with its entire action context, which can contain information or can be NULL
.
The client performs actions based on the results returned by the rules engine. The rules engine does not perform actions based on rule evaluations.
See Also:
Oracle Database PL/SQL Packages and Types Reference for more information about the DBMS_RULE.EVALUATE
procedure
"Rule Conditions with Undefined Variables that Evaluate to NULL" for information about Streams clients and maybe_rules
Partial evaluation occurs when the DBMS_RULE.EVALUATE
procedure is run without data for all the tables and variables in the specified evaluation context. During partial evaluation, some rules can reference columns, variables, or attributes that are unavailable, while some other rules can reference only available data.
For example, consider a scenario where only the following data is available during evaluation:
Column tab1.col
=
7
Attribute v1.a1
=
'ABC'
The following rules are used for evaluation:
Rule R1
has the following condition:
(tab1.col = 5)
Rule R2
has the following condition:
(:v1.a2 > 'aaa')
Rule R3
has the following condition:
(:v1.a1 = 'ABC') OR (:v2 = 5)
Rule R4
has the following condition:
(:v1.a1 = UPPER('abc'))
Given this scenario, R1
and R4
reference available data, R2
references unavailable data, and R3
references available data and unavailable data.
Partial evaluation always evaluates only simple conditions within a rule. If the rule condition has parts which are not simple, then the rule might or might not be evaluated completely, depending on the extent to which data is available. If a rule is not completely evaluated, then it can be returned as a MAYBE
rule.
Given the rules in this scenario, R1
and the first part of R3
are evaluated, but R2
and R4
are not evaluated. The following results are returned to the client:
R1
evaluates to FALSE
, and so is not returned.
R2
is returned as MAYBE
because information about attribute v1.a2
is not available.
R3
is returned as TRUE
because R3
is a simple rule and the value of v1.a1
matches the first part of the rule condition.
R4
is returned as MAYBE
because the rule condition is not simple. The client must supply the value of variable v1
for this rule to evaluate to TRUE
or FALSE
.
See Also:
"Simple Rule Conditions"You can create the following types of database objects directly using the DBMS_RULE_ADM
package:
Evaluation contexts
Rules
Rule sets
You can create rules and rule sets indirectly using the DBMS_STREAMS_ADM
package. You control the privileges for these database objects using the following procedures in the DBMS_RULE_ADM
package:
GRANT_OBJECT_PRIVILEGE
GRANT_SYSTEM_PRIVILEGE
REVOKE_OBJECT_PRIVILEGE
REVOKE_SYSTEM_PRIVILEGE
To allow a user to create rule sets, rules, and evaluation contexts in the user's own schema, grant the user the following system privileges:
CREATE_RULE_SET_OBJ
CREATE_RULE_OBJ
CREATE_EVALUATION_CONTEXT_OBJ
These privileges, and the privileges discussed in the following sections, can be granted to the user directly or through a role.
Note:
When you grant a privilege on"ANY"
object (for example, ALTER_ANY_RULE
), and the initialization parameter O7_DICTIONARY_ACCESSIBILITY
is set to false
, you give the user access to that type of object in all schemas except the SYS
schema. By default, the initialization parameter O7_DICTIONARY_ACCESSIBILITY
is set to false
.
If you want to grant access to an object in the SYS
schema, then you can grant object privileges explicitly on the object. Alternatively, you can set the O7_DICTIONARY_ACCESSIBILITY
initialization parameter to true
. Then privileges granted on "ANY"
object will allow access to any schema, including SYS
.
See Also:
"The Components of a Rule" for more information about these database objects
Oracle Database PL/SQL Packages and Types Reference for more information about the system and object privileges for these database objects
Oracle Database Concepts and Oracle Database Security Guide for general information about user privileges
Chapter 6, "How Rules Are Used in Streams" for more information about creating rules and rule sets indirectly using the DBMS_STREAMS_ADM
package
To create an evaluation context, rule, or rule set in a schema, a user must meet at least one of the following conditions:
The schema must be the user's own schema, and the user must be granted the create system privilege for the type of database object being created. For example, to create a rule set in the user's own schema, a user must be granted the CREATE_RULE_SET_OBJ
system privilege.
The user must be granted the create any system privilege for the type of database object being created. For example, to create an evaluation context in any schema, a user must be granted the CREATE_ANY_EVALUATION_CONTEXT
system privilege.
Note:
When creating a rule with an evaluation context, the rule owner must have privileges on all objects accessed by the evaluation context.To alter an evaluation context, rule, or rule set, a user must meet at least one of the following conditions:
The user must own the database object.
The user must be granted the alter object privilege for the database object if it is in another user's schema. For example, to alter a rule set in another user's schema, a user must be granted the ALTER_ON_RULE_SET
object privilege on the rule set.
The user must be granted the alter any system privilege for the database object. For example, to alter a rule in any schema, a user must be granted the ALTER_ANY_RULE
system privilege.
To drop an evaluation context, rule, or rule set, a user must meet at least one of the following conditions:
The user must own the database object.
The user must be granted the drop any system privilege for the database object. For example, to drop a rule set in any schema, a user must be granted the DROP_ANY_RULE_SET
system privilege.
This section describes the privileges required to place a rule in a rule set. The user must meet at least one of the following conditions for the rule:
The user must own the rule.
The user must be granted the execute object privilege on the rule if the rule is in another user's schema. For example, to place a rule named depts
in the hr
schema in a rule set, a user must be granted the EXECUTE_ON_RULE
privilege for the hr.depts
rule.
The user must be granted the execute any system privilege for rules. For example, to place any rule in a rule set, a user must be granted the EXECUTE_ANY_RULE
system privilege.
The user also must meet at least one of the following conditions for the rule set:
The user must own the rule set.
The user must be granted the alter object privilege on the rule set if the rule set is in another user's schema. For example, to place a rule in the human_resources
rule set in the hr
schema, a user must be granted the ALTER_ON_RULE_SET
privilege for the hr.human_resources
rule set.
The user must be granted the alter any system privilege for rule sets. For example, to place a rule in any rule set, a user must be granted the ALTER_ANY_RULE_SET
system privilege.
In addition, the rule owner must have privileges on all objects referenced by the rule. These privileges are important when the rule does not have an evaluation context associated with it.
To evaluate a rule set, a user must meet at least one of the following conditions:
The user must own the rule set.
The user must be granted the execute object privilege on the rule set if it is in another user's schema. For example, to evaluate a rule set named human_resources
in the hr
schema, a user must be granted the EXECUTE_ON_RULE_SET
privilege for the hr.human_resources
rule set.
The user must be granted the execute any system privilege for rule sets. For example, to evaluate any rule set, a user must be granted the EXECUTE_ANY_RULE_SET
system privilege.
Granting EXECUTE
object privilege on a rule set requires that the grantor have the EXECUTE
privilege specified WITH
GRANT
OPTION
on all rules currently in the rule set.
To use an evaluation context in a rule or a rule set, the user who owns the rule or rule set must meet at least one of the following conditions for the evaluation context:
The user must own the evaluation context.
The user must be granted the EXECUTE_ON_EVALUATION_CONTEXT
privilege on the evaluation context, if it is in another user's schema.
The user must be granted the EXECUTE_ANY_EVALUATION_CONTEXT
system privilege for evaluation contexts.