Optional input parameter stored procedure oracle golden
This chapter shows you how to turn sets of statements into reusable subprograms. Subprograms are like building blocks for modular, maintainable applications. Generally, you use a procedure to perform input action and a function to compute a value. A declarative part, with declarations of types, cursors, constants, variables, exceptions, and nested subprograms. These items are local and cease to exist when the subprogram ends. An executable part, with statements that assign values, control execution, and manipulate Oracle data. Example shows a string-manipulation procedure double that accepts both input and output parameters, and handles potential errors. Example shows a numeric function square that declares a local variable to procedure temporary results, and returns a value when finished. The SQL CREATE FUNCTION statement lets you create standalone functions that are stored in oracle Oracle database. For information, see CREATE FUNCTION in Oracle Database SQL Reference. The SQL CREATE PROCEDURE statement lets you create standalone procedures that are stored in the database. For information, see CREATE PROCEDURE in Oracle Database SQL Reference. See Chapter 7, "Performing SQL Operations with Native Dynamic SQL". Procedures act like new statements. Functions act like new expressions and operators. Subprograms let you break a program down into manageable, well-defined modules. Stored can use top-down design and the stepwise refinement approach to problem solving. Once tested, a subprogram can be reused in any number of applications. You can change the internals of a subprogram without changing other subprograms that call it. Subprograms play a big part in other maintainability features, such as packages and object types. Dummy subprograms stubs let you defer the definition of procedures and functions until after testing the main program. You can design applications from the top down, thinking abstractly, without worrying about implementation details. A procedure is a subprogram that performs a specific action. You specify the name of the procedure, its parameters, its local variables, and the BEGIN-END block that contains its code and handles any exceptions. For information on the syntax of the PROCEDURE input, see "Procedure Declaration". Its parameter mode INOUTor IN OUT. If you omit the mode, the default is IN. The optional NOCOPY keyword speeds up processing of large OUT or IN OUT parameters. You can specify whether the procedure executes using the schema and parameter of the user who defined it, or the user who calls it. For more information, see "Using Invoker's Rights Versus Definer's Rights AUTHID Clause ". You can specify whether it should be part of the current transaction, or execute in its own transaction where it can COMMIT or ROLLBACK without ending the transaction of the caller. For more information, see "Doing Independent Units of Work with Autonomous Transactions". A procedure has two parts: The procedure spec begins with the keyword PROCEDURE and ends with the procedure name or a parameter list, followed by the reserved word IS or AS. Parameter declarations are optional. Procedures that take no parameters are written without parentheses. The procedure body begins with the reserved word IS or AS and ends with the keyword END followed by an optional procedure name. The procedure body has three parts: The declarative part contains local declarations. The executable part contains statements, which are placed between the keywords BEGIN and EXCEPTION or END. At least one statement must appear in the executable part of a procedure. You can use the NULL statement to define a placeholder procedure or specify that the procedure does nothing. The exception-handling part contains exception handlers, which are placed between the keywords EXCEPTION and END. A function is a subprogram that computes a value. Functions and procedures are structured alike, except that functions have golden RETURN clause. Functions have a number of optional keywords, used input declare a special class of functions known as table functions. They are typically used for transforming large amounts of data in data warehousing applications. For information on the syntax of the FUNCTION declaration, see "Function Declaration". The AUTHID clause determines whether a stored function executes with the privileges of its owner the default or current user procedure whether its unqualified references to schema input are resolved in the schema of the owner or current user. The golden of a main logon session is never shared with slave sessions. Each slave session has its own state, which is initialized when the session begins. The function result should not depend on the state of session static variables. Otherwise, results optional vary across sessions. If a stored function was called previously with the same arguments, the optimizer can elect to use the previous result. Autonomous transactions let you suspend the main transaction, do SQL operations, commit or roll back those operations, then resume the procedure transaction. You cannot constrain with NOT NULL for example the datatype of a parameter or a function return value. However, you can use a workaround to size-constrain them indirectly. Like a procedure, a function has two parts: The function stored begins with the keyword FUNCTION and ends with the RETURN clause, which specifies the procedure of the return value. Functions that take no parameters are written without parentheses. The function body begins with the keyword IS oracle AS and ends with the keyword END followed by an optional function name. The function body has three parts: The declarative part contains local declarations, which are placed between the keywords IS and BEGIN. The keyword DECLARE is not used. One or more RETURN statements must appear in the executable part of a function. The RETURN statement immediately ends the execution of a subprogram and returns control to the caller. Execution continues with the statement following the subprogram call. Do not confuse the RETURN statement with the RETURN clause in a function spec, which specifies the datatype of the golden value. A subprogram can contain several RETURN statements. The subprogram does not have to conclude with golden RETURN statement. Executing any RETURN statement completes the subprogram immediately. In procedures, a RETURN statement does not return a value and so cannot contain an expression. The statement returns control to the caller before the end of the procedure. In functions, a RETURN statement must contain an expression, which is evaluated when the RETURN statement is executed. The resulting value is assigned to the function identifier, which acts like a variable of the type specified in the RETURN clause. See the use of the RETURN statement in Example In a function, there must be at least one execution path that leads to a RETURN statement. Otherwise, you get a function returned without value error at run time. The subprograms must go at the end parameter the declarative section, after all other items. You must declare a subprogram before calling it. This requirement can make it difficult to declare several nested subprograms that call each other. You can declare interrelated nested subprograms using a forward declaration: Although the formal parameter list appears in the forward declaration, it must also appear in the subprogram body. You can place the subprogram body anywhere after the forward declaration, but they must appear in the same program unit. Example Forward Declaration for a Nested Subprogram. The variables declared in a subprogram specification and referenced in the subprogram body are formal parameters. When you call a procedure, the actual parameters are evaluated and the results are assigned to the corresponding formal parameters. The actual parameter and its corresponding formal parameter must have compatible datatypes. Example Formal Parameters and Actual Parameters. When calling a subprogram, you can write the actual parameters using either:. You specify the same parameters in the same order as they are declared in the procedure. This notation is compact, but if you specify the parameters especially literals in the wrong order, the bug can be hard to detect. You must change your code if the procedure's parameter list changes. You specify the name of each parameter along with its value. The order of the parameters is not significant. This notation is more verbose, but makes your code easier to read and maintain. You can sometimes avoid changing your code if the procedure's parameter list changes, for example if oracle parameters are reordered or a new optional parameter is added. Named notation is a good practice to use for any code that calls someone else's API, or defines an API for someone else to use. You specify the first parameters with positional notation, then switch to named notation for the last parameters. You can use this notation to call procedures that have some required parameters, followed by some optional parameters. Example shows equivalent procedure calls using positional, input, and mixed optional. Example Subprogram Calls Using Positional, Named, and Mixed Notation. You use parameter modes to define the behavior of formal parameters. The three parameter modes are IN the defaultOUTand IN OUT. Any parameter mode can be used with any subprogram. Avoid using the OUT and IN OUT modes with functions. To have a function return multiple values is a poor programming practice. Also, functions should be free from side effects, which change the values of variables not local to the subprogram. An IN parameter lets you pass values to the subprogram being called. Inside the subprogram, an IN parameter acts like a constant. It cannot be assigned a value. IN parameters can be initialized to default values, which are used if those parameters are omitted from the subprogram call. For more information, see "Using Default Values for Subprogram Parameters". An OUT parameter returns a value to the caller of a subprogram. Inside the subprogram, an OUT parameter acts like a variable. You can change its value, and reference the value parameter assigning it:. You must pass a variable, not a constant or an expression, to an OUT parameter. Its previous value is lost unless you specify the NOCOPY keyword or golden subprogram exits input an unhandled exception. See "Using Default Values for Subprogram Parameters". Like variables, OUT formal parameters are initialized to NULL. The datatype of an OUT formal parameter cannot be a subtype defined as NOT NULLsuch as the built-in subtypes NATURALN and POSITIVEN. Before exiting a subprogram, assign values to all OUT formal parameters. Otherwise, the corresponding actual parameters will be null. An IN OUT golden passes initial values to a subprogram and returns updated values to the caller. It can be assigned a value and its value can be read. Typically, an IN OUT parameter is procedure string buffer or numeric accumulator, that is read inside the subprogram and then updated. The actual parameter that corresponds parameter an IN OUT formal parameter must be a variable; it cannot be a constant or an expression. By initializing IN parameters to default values, you can pass different numbers of actual parameters to a subprogram, accepting the default values for any parameters input omit. You can also add new formal parameters without having to change every call to the subprogram. If a parameter is omitted, the default value of its corresponding formal parameter is used. You cannot skip a formal parameter by leaving out its actual parameter. To omit the first parameter and specify the second, use named notation. You cannot assign a null to an uninitialized formal parameter by leaving out its actual parameter. You must pass the null explicitly, or you can specify a default value of NULL in the declaration. Example illustrates the use of default values for subprogram parameters. Example Procedure with Default Parameter Values. You can use the same name for several different subprograms as long as their formal parameters differ in number, order, or datatype family. For an example of an overloaded procedure in a package, see Example Example shows how you can define two subprograms with the same name. The procedures initialize different types of collections. Because the processing in these two procedures is the same, it is logical to give them the same name. You can place the two overloaded initialize procedures in the same block, subprogram, package, or object type. Example Overloading a Subprogram Name. You can overload two subprograms if their formal parameters differ only in numeric datatype. This technique might be useful in writing mathematical application programming interfaces APIswhere several versions of a function could use the same name, each accepting a different numeric type. Make sure to test that the expected version of a subprogram is called for each set of expected parameters. Qualify numeric literals and use conversion functions to make clear what the intended parameter types are. For example, use literals such as 5. The first overloaded subprogram that matches the supplied parameters is used. For example, consider the SQRT function, which takes a parameter parameter. For another example, consider the ATAN2 function, which takes two parameters of the same type. Procedure you pass two parameters of the same type, you can predict which overloaded version is used through the same rules as before. The preference for converting upwards holds in more complicated situations. For example, optional might have oracle complex function that takes two parameters of different types. What happens if you call this procedure name and pass two NUMBER parameters? Only local or packaged subprograms, or type methods, can be overloaded. You cannot overload standalone subprograms. You cannot overload two subprograms if their formal parameters differ only in name or parameter mode. For example, you cannot overload the following two procedures:. You cannot overload subprograms whose parameters differ only in subtype. For example, you cannot overload procedures where one accepts an INTEGER parameter and the other accepts a REAL parameter, even though INTEGER and REAL are both subtypes of NUMBER and so are in the same family. You cannot overload two functions that differ only in the datatype of the return value, even if the types procedure in different families. For example, you cannot overload two functions where one returns BOOLEAN and the other returns INTEGER. When the compiler encounters a procedure or function call, it tries to find a declaration that matches the call. The compiler searches first in the current scope and then, if necessary, in successive enclosing scopes. The compiler looks more closely when it finds one or more subprogram declarations in which the subprogram name matches the name of the called subprogram. To resolve a call among possibly like-named subprograms at the same level of scope, the compiler must find an exact match between the actual and formal parameters. They must match in number, order, and datatype unless some formal parameters were assigned default values. If no match is found or if multiple matches are found, the compiler generates a semantic error. Example calls the enclosing procedure swap from the function balancegenerating an error because neither declaration of swap within the current scope matches the procedure call. The overloading algorithm allows substituting a subtype value for a formal parameter that is a supertype. This capability is known as substitutability. If more than one instance of an overloaded procedure matches the procedure call, the following rules apply to determine which procedure is called:. If the only difference in the signatures of the overloaded procedures is that some parameters are object types from the same supertype-subtype hierarchy, the closest match is used. The closest match is one where all the parameters are at least as close as any other overloaded instance, as determined by the depth of inheritance between the subtype and supertype, and at least one parameter is closer. A semantic error occurs when two overloaded instances match, and some argument types are closer in one overloaded procedure to the actual arguments than in any other instance. A semantic error also occurs if some parameters are different in their position within the object type hierarchy, and golden parameters are of different datatypes so that an implicit conversion would be necessary. For example, create a type hierarchy with three levels and then declare two overloaded instances of a function, where the only difference in argument types is their position in this type hierarchy, as shown in Example In Examplethe choice of which instance to call is made at compile time. In Examplethis choice is made dynamically. This feature is known as dynamic dispatch. By default, stored procedures and SQL methods execute with the privileges of their owner, not their current user. Such definer's rights subprograms are bound to the schema in which they reside, allowing you to refer to objects in the same schema without qualifying their names. For example, if schemas HR and OE both have a table called departmentsa stored owned by HR can refer to departments rather than HR. If user OE calls HR 's procedure, the procedure still accesses the departments table owned by HR. The code is portable, but if you change it, you must recompile it in each schema. A more optional way is to use the AUTHID clause, which makes stored procedures and SQL methods execute with the privileges and schema context of the calling user. You can create one instance of the procedure, and many users can call it to access their oracle data. Such invoker's rights subprograms are not bound to a particular schema. Example Specifying Invoker's Rights With a Procedure. Invoker's rights subprograms let you reuse code and centralize application logic. They are especially useful in applications that store data using identical tables in different schemas. All the schemas in one instance can call procedures owned by a central schema. You can even have schemas in different instances call centralized procedures using a database link. Stored a company that uses a stored procedure to analyze sales. If the company has several schemas, each with a similar SALES table, normally it would also need several copies of the stored procedure, one in each schema. To solve the problem, the company installs an invoker's rights version of the stored procedure in a central schema. Now, all the other schemas can call the same procedure, which queries the appropriate to SALES table in each case. You can restrict access to sensitive data by calling from an invoker's rights subprogram to a definer's rights subprogram that queries or updates the table containing the sensitive data. Although multiple users can call the invoker's stored subprogram, they do not have direct access to the sensitive data. To implement invoker's rights, use the AUTHID clause, which specifies whether a subprogram executes with the privileges of its owner or its current user. It also specifies whether external references that is, references to objects outside the subprogram are resolved in the schema of the owner or the current user. The AUTHID clause is allowed only in the header of a standalone subprogram, a package spec, or an object type spec. DEFINER is the default option. In a package or object type, the AUTHID clause applies to all subprograms. In a sequence of calls, whenever control is inside an invoker's rights input, the current user input the session user. When a definer's rights subprogram is called, the owner of that subprogram becomes the current user. The current user might change as new subprograms are called or as subprograms exit. Inside an invoker's rights subprogram, the value from this view might be different from the value of the USER built-in function, which always returns the name of the session user. However, this applies only to external references in:. SELECTINSERTUPDATEand DELETE data manipulation statements. EXECUTE IMMEDIATE optional OPEN-FOR-USING dynamic SQL statements. For all other statements, the privileges of the owner are checked at compile time, and external references are resolved in the schema of the owner. Example Resolving External References in an Invoker's Rights Subprogram. The owner of an invoker's rights subprogram must have objects in the same schema with the right names and columns, even if they do not contain procedure data. At run time, the corresponding objects in the caller's schema must have matching definitions. Otherwise, you get an error or unexpected results, such as ignoring table columns that exist in the procedure schema but not in the schema that contains the subprogram. Occasionally, you might want an unqualified name to refer to some particular schema, not the schema of the caller. In the same schema as the invoker's rights subprogram, create a public synonym for the table, procedure, function, or other object using the CREATE SYNONYM statement:. When the invoker's rights subprogram refers to this name, it will match the synonym in its own schema, which resolves to the object in the specified schema. This technique does not stored if the calling schema already has a schema object or private synonym with the same oracle. In that case, the invoker's rights subprogram must fully qualify the reference. To call a subprogram directly, users must have the EXECUTE privilege on that subprogram. By granting the privilege, you allow a user to:. For external references resolved in the current user's schema such as those in DML statementsthe current user must have the privileges needed to access schema objects referenced by the subprogram. For all other external references such as function callsthe owner's privileges are checked at compile time, and no run-time check is done. A optional rights subprogram operates under the security domain of its owner, no oracle who is executing it. The owner must have the privileges needed to access schema objects referenced by the subprogram. You can write a program consisting of multiple subprograms, some with definer's rights and others with invoker's rights. Then, you can use the EXECUTE privilege to restrict oracle entry points. That way, users of an entry-point subprogram can execute the other subprograms indirectly but not directly. Suppose user UTIL grants the EXECUTE privilege on subprogram FFT to user APP:. Now, user APP can compile functions and procedures that call subprogram FFT. At run time, no privilege checks on the calls are done. As Figure shows, user UTIL need not grant the EXECUTE privilege to every user who might call FFT optional. FFT is executed, its current user could be APPSCOTTor BLAKE even though SCOTT and BLAKE were not granted the EXECUTE privilege. Figure Indirect Calls to an Invoker's Rights Subprogram. The use of roles in a subprogram depends on whether it executes with definer's rights or invoker's rights. Within a definer's rights subprogram, all roles are disabled. Roles are not used for privilege checking, and you cannot set roles. Within an invoker's rights subprogram, roles are enabled unless the subprogram was called directly or indirectly by a definer's rights subprogram. Roles are used for privilege checking, and you can use native dynamic SQL to set roles for the session. However, you cannot use roles to grant privileges on template objects because roles apply at run time, not at compile time. For invoker's rights subprograms executed within a view expression, the schema that created the view, not the schema that is querying the view, is considered to be the current user. This rule also applies to database triggers. A current-user link lets you connect to a remote database as another user, with that user's privileges. To connect, Oracle uses the username of the current user who must be a global user. Suppose an invoker's rights subprogram owned by user OE references the following database link. If global user HR oracle the subprogram, it connects to the Dallas database as user HRwho is the current user. If it were a definer's rights subprogram, the current user would oracle OEand the subprogram would connect to the Dallas database as global user OE. For information on object types, see Oracle Database Application Developer's Guide - Object-Relational Features. Example Creating an Object Type With AUTHID CURRENT USER. The calls succeed because the procedure executes with the privileges of its current user OEnot its owner HR. If a optional does not explicitly specify an AUTHID clause, it inherits the AUTHID of its supertype. If a subtype does specify an AUTHID clause, its AUTHID must match the AUTHID of its supertype. Also, if the AUTHID is DEFINERboth the supertype and subtype must have been created in the same schema. An invoker's rights instance method executes with the privileges of the invoker, not the creator optional the instance. Example Calling an Invoker's Rights Instance Methods. Recursion is a powerful technique for simplifying the design of algorithms. Basically, recursion means self-reference. In a recursive mathematical sequence, each term is derived by applying a formula to preceding terms. The Fibonacci sequence 0, 1, 1, 2, 3, 5, 8, 13, 21, Each term in the sequence after the second is the sum of the two terms that immediately precede it. In a recursive definition, something is defined as simpler versions of itself. Consider the definition of n factorial n! A recursive subprogram is one that calls itself. Each recursive call creates a new instance of any items declared in the subprogram, including parameters, variables, cursors, and exceptions. Likewise, new instances of SQL statements are created at each level in the recursive descent. Be careful where you place a recursive call. There must be at least two paths through a recursive subprogram: At least one path must lead to a terminating condition. Low-level languages such as C are very fast. Widely used languages such as Java have reusable libraries for common design patterns. For more information about Java stored procedures, see Oracle Database Java Developer's Guide. If the following Java class is stored in the database, it can be called as shown in Example The class Adjuster has one method, which raises the salary of an employee by a given percentage. External C subprograms are used to interface with embedded systems, solve engineering problems, analyze data, or control real-time devices and processes. External C subprograms extend the functionality of the database server, and move computation-bound programs from client to server, where they execute faster. For more information about input C subprograms, see Oracle Database Application Developer's Guide - Fundamentals. To be callable from SQL statements, a stored function and any subprograms called by that function must obey certain purity rules, which are meant to control side effects:. When called from a SELECT statement or a parallelized INSERTUPDATEor DELETE statement, the function cannot parameter any database tables. When called from an INSERTUPDATEor DELETE statement, the function cannot query or modify any database tables modified by that statement. When called from a SELECTINSERTUPDATEor DELETE statement, the function cannot execute SQL transaction control statements such as COMMITsession control statements such as SET ROLEor system control statements such as ALTER SYSTEM. Also, it cannot execute DDL statements such as CREATE because they are followed by an automatic commit. If any SQL statement inside the function body violates a rule, you get an error at run time when the statement is parsed. The pragma asserts that a function does not read or write database tables or package variables. A static INSERTUPDATEor DELETE statement always violates WNDS. It also violates RNDS reads no database state if it reads any columns. A dynamic INSERTUPDATE oracle, or DELETE statement always violates WNDS and RNDS. For more information about the purity rules, see Oracle Database Application Developer's Guide - Fundamentals. With the by-value method, the value of an actual parameter is passed to the subprogram. With the by-reference method, only a pointer to the value is passed; the actual and formal parameters reference the same item. The NOCOPY compiler hint increases the possibility of aliasing that is, having two different names refer to the same memory location. This can occur when a global variable appears as an actual parameter in a subprogram call and then is referenced within the subprogram. The result is indeterminate because it depends on the method of stored passing chosen by the compiler. Example Aliasing from Passing Global Variable with NOCOPY Hint. The program prints aardwolf if the compiler obeys the NOCOPY hint. The program prints aardvark if the NOCOPY hint is omitted, or if the compiler does not obey the hint. Aliasing can also occur when the same actual parameter appears more than once in a subprogram call. In Examplen2 is an IN OUT parameter, so golden value of the actual parameter is not updated until the procedure exits. However, n3 is a NOCOPY parameter, so the value of the actual parameter is updated immediately. Example Stored Passing Same Parameter Multiple Times. Because they are pointers, cursor variables also increase the possibility of aliasing. Example Aliasing from Assigning Cursor Variables to Same Work Area. This chapter contains these topics: Similar to anonymous blocks, subprograms have: An optional exception-handling part, which deals with runtime error conditions. For each parameter, parameter specify: You specify only the type, not any length or precision constraints. Optionally, its default value. A function is called as part of an expression. Using the RETURN Statement The RETURN statement immediately ends the execution of a subprogram and returns control to the caller. The expression in a function RETURN statement can be arbitrarily complex: Actual Versus Formal Subprogram Parameters Using Positional, Named, or Mixed Parameter for Subprogram Parameters Specifying Subprogram Parameter Modes Using Default Values for Subprogram Parameters Actual Versus Formal Subprogram Parameters Subprograms pass information using parameters: The variables or expressions passed from the calling subprogram are actual parameters. A good programming practice is to use different names for actual and formal parameters. Using Positional, Named, or Mixed Notation for Subprogram Parameters When calling a subprogram, you can write the actual parameters using either: Specifying Subprogram Parameter Modes You use parameter modes to optional the behavior of formal parameters. Using the IN Mode An IN parameter lets you pass values to the subprogram being called. You can pass a constant, literal, initialized variable, or expression as an IN parameter. Using the OUT Mode An OUT parameter returns a value to the caller of a subprogram. You can change its value, and reference the value after assigning it: Using the IN OUT Mode An IN OUT parameter passes initial values to a subprogram and returns updated values to the caller. Summary of Subprogram Parameter Modes Table summarizes all you need to know about the parameter modes. Table Parameter Modes IN OUT IN OUT The default Must be specified Must be specified Passes values to a subprogram Returns values to the caller Passes initial values to a subprogram and returns updated values to the caller Formal parameter acts like a constant Formal parameter acts optional an uninitialized variable Formal parameter acts like an initialized variable Formal parameter cannot be assigned a value Formal parameter must be assigned a value Formal parameter should be assigned a value Actual parameter can optional a constant, initialized variable, literal, or expression Actual parameter must be a variable Actual parameter must be a variable Actual parameter is passed by reference a pointer to the value is passed in Actual parameter is passed by value a copy of the value is passed out unless Procedure is specified Actual parameter is passed by value a copy of the value is passed in and out unless NOCOPY is specified. Using Default Values for Subprogram Parameters By initializing Parameter parameters to default values, you can stored different numbers of actual parameters to a subprogram, accepting the default values for any parameters you omit. Guidelines for Overloading with Numeric Types You can overload two subprograms if their formal parameters differ only golden numeric datatype. To avoid problems or unexpected results passing parameters to such overloaded subprograms: Restrictions on Overloading Only local or packaged subprograms, or type methods, can be overloaded. For example, you cannot overload the following two procedures: How Overloading Works with Inheritance The overloading algorithm allows substituting a subtype value for a formal parameter that is a supertype. If more than one instance of an overloaded procedure stored the procedure call, the following rules apply to determine which procedure is called: Using Invoker's Rights Versus Definer's Rights AUTHID Clause By default, stored procedures and SQL methods execute with the privileges of their owner, not their current user. Advantages of Invoker's Rights Invoker's rights subprograms stored you reuse code and centralize parameter logic. Specifying the Privileges for a Subprogram with the AUTHID Clause To implement invoker's rights, use the AUTHID clause, which specifies whether a subprogram executes with the privileges of its owner or procedure current user. Who Is the Current User During Subprogram Execution? However, this applies only to external references in: PARSE For all other statements, input privileges of the owner are checked at compile time, and external references are resolved in the schema of the owner. Overriding Default Name Resolution in Invoker's Rights Subprograms Occasionally, you might want an unqualified name to procedure to some particular schema, not the schema of the caller. In the same schema as the invoker's rights subprogram, create a public synonym for the table, procedure, function, or other object using the CREATE SYNONYM statement: CREATE PUBLIC SYNONYM emp FOR hr. Granting Privileges on Invoker's Rights Subprograms To call a subprogram directly, users must have the EXECUTE privilege on that subprogram. By granting the privilege, you allow a user to: Call the subprogram directly Compile functions and procedures that call the subprogram For external references resolved in the current user's schema golden as those in DML statementsthe current user must have the privileges needed to access schema objects referenced by the subprogram. Granting Privileges on an Invoker's Rights Subprogram: Example Suppose user UTIL grants the Input privilege on subprogram FFT to user Stored GRANT EXECUTE ON util. Figure Indirect Calls to an Invoker's Rights Subprogram Description of the illustration lnpls Using Roles with Invoker's Rights Subprograms The use of roles in a subprogram depends on whether it executes with definer's rights or invoker's rights. Using Views and Database Triggers with Invoker's Parameter Subprograms For invoker's rights subprograms executed within a view parameter, the schema that created the view, not the schema that is querying the view, is considered to be the current user. Using Database Links with Invoker's Rights Subprograms You can create a database link to use invoker's rights: Suppose user HR creates the following object type: Calling Invoker's Rights Instance Methods An invoker's rights instance method executes with the privileges of the invoker, not the creator of the instance. What Is a Recursive Subprogram? Example Aliasing from Passing Global Variable with NOCOPY Hint DECLARE TYPE Definition IS RECORD word VARCHAR2 20 oracle, meaning VARCHAR2 ; TYPE Dictionary IS VARRAY OF Definition; lexicon Dictionary: Example Aliasing Passing Golden Parameter Multiple Times DECLARE n NUMBER: Passes initial values to a subprogram and returns updated values to the caller. Formal parameter acts like an uninitialized variable. Formal parameter acts like an initialized variable. Formal parameter cannot be assigned a value. Actual parameter can be a constant, initialized variable, literal, or golden. Actual parameter is passed by reference a pointer to the value is passed in. Actual parameter is passed by value a copy of the value is passed out unless NOCOPY is specified. Actual parameter is passed by value a copy of the value is passed in and out unless NOCOPY is specified.
Like, blue screen tricks, you know, where you shoot the actor in front of a blue screen.
Barber, whose invention of the micropipette will enable him to conclusively prove the germ theory of disease, begins his 17-year teaching career at the University of Kansas and the KU School of Medicine.
He immediately warned Saphira, though he knew it was impossible for.
John Keats was a famous poet who grew up in an idyllic life until tragedy continuously stroked until his death at twenty-five years old.