Oracle Built−in Packages- P161 ppsx

PROCEDURE TenPctIncrease IS BEGIN UPDATE prices SET price_wholesale = price_wholesale * 1.10, price_retail = price_retail * 1.10; END TenPctIncrease; END PriceMaint; / Now, suppose that we wish to make a 10% price increase at all of our locations (i.e., all locations in the DEFDEFAULTDEST data dictionary view). We could create a procedure that queues a call to PriceMaint.TenPctIncrease to all of these sites. In this case, we issue the TRANSACTION call without parameters: CREATE OR REPLACE PROCEDURE TenPctPriceHike IS BEGIN DBMS_DEFER.TRANSACTION; DBMS_DEFER.CALL( schema_name => 'SPROCKET', package_name => 'PRICEMAINT', proc_name => 'TENPCTINCREASE' arg_count => 0 ); DBMS_DEFER.COMMIT_WORK(commit_work_comment=>'No nodes or args needed'); END; Because the nodes parameter isn't specified in either the call to TRANSACTION or the call to CALL, Oracle resolves the destinations by using all sites in the DEFDEFAULTDEST data dictionary view. Here is how you might use the TenPctPriceHike Procedure. Confirm the default destinations: SQL> SELECT * FROM defdefaultdest; DBLINK −−−−−−−−−−−−−−−−−−−− D7NY.BIGWHEEL.COM D7OH.BIGWHEEL.COM D7OR.BIGWHEEL.COM D7WA.BIGWHEEL.COM D7TX.BIGWHEEL.COM 5 rows selected. Now use TenPctPriceHike to queue the RPC to all five destinations: SQL> EXECUTE TenPctPriceHike PL/SQL procedure successfully completed. Figure 17−1 graphically illustrates how a deferred call is queued. Figure 17.1: Queueing up a deferred call to TenPctIncrease [Appendix A] What's on the Companion Disk? 17.3.2 Basic RPCs 791 Now check the entries in DEFTRAN (this call was made from D7CA. BIGWHEEL.COM): SQL> select * from deftrandest; DEFERRED_TRAN_ID DEFERRED_TRAN_DB DBLINK −−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−− 2.44.13 D7CA.BIGWHEEL.COM D7NY.BIGWHEEL.COM 2.44.13 D7CA.BIGWHEEL.COM D7OH.BIGWHEEL.COM 2.44.13 D7CA.BIGWHEEL.COM D7OR.BIGWHEEL.COM 2.44.13 D7CA.BIGWHEEL.COM D7WA.BIGWHEEL.COM 2.44.13 D7CA.BIGWHEEL.COM D7TX.BIGWHEEL.COM 5 rows selected. For an additional example, see the deftdest.sql file on the companion disk. The example queries the DEFTRANDEST data dictionary view and lists destination databases for deferred RPC calls. NOTE: Procedure TenPctPriceHike queues the deferred RPC only if the owner of the procedure has EXECUTE privileges on DBMS_DEFER. 17.3.2.3.4 Specifying nondefault destinations with TRANSACTION What if we wanted to apply the 10% price hike only to our West Coast sites (i.e., D7CA.BIGWHEEL.COM, D7OR.BIGWHEEL.COM, and D7WA.BIGWHEEL.COM)? The following example does just that by specifying the nodes parameter in the TRANSACTION procedure: CREATE OR REPLACE PROCEDURE TenPctPriceHikeWest IS vNodes DBMS_DEFER.NODE_LIST_T; BEGIN vNodes(1) := 'D7CA.BIGWHEEL.COM'; vNodes(2) := 'D7OR.BIGWHEEL.COM'; vNodes(3) := 'D7WA.BIGWHEEL.COM'; DBMS_DEFER.TRANSACTION( vNodes ); DBMS_DEFER.CALL( schema_name => 'SPROCKET', package_name => 'PRICEMAINT', [Appendix A] What's on the Companion Disk? 17.3.2 Basic RPCs 792 proc_name => 'TENPCTINCREASE' arg_count => 0 ); DBMS_DEFER.COMMIT_WORK(commit_work_comment=>'West Coast Price Hike'); END; 17.3.2.3.5 Committing deferred RPC calls with COMMIT_WORK Notice that the last two examples include a call to DBMS_DEFER.COMMIT_WORK. All deferred RPCs queued with the CALL procedure must be followed by a call to COMMIT_WORK; an explicit COMMIT or COMMIT WORK is not sufficient. The reason for this restriction is that COMMIT_WORK not only commits the transaction, but also updates the commit_comment and delivery_order field in the DEFTRANS data dictionary view. The commit_comment is updated with the optional string passed to COMMIT_WORK, and the delivery_order field is updated with the transaction's SCN. Remember that the TRANSACTION procedure is not required to queue deferred calls. It is used only to specify destinations. The real power and flexibility of deferred transactions is in the CALL procedure. For an additional example, see the defcdest.sql file on the companion disk. The example queries the DEFCALLDEST data dictionary view and lists the destination databases of all calls in the deferred call queue. 17.3.3 Parameterized RPCs The preceding sections describe the simple version of building deferred RPCs with the DBMS_DEFER package. We saw in those sections that the DBMS_DEFER.CALL procedure is the program that actually queues deferred RPCs. Most of the examples we have seen so far use it in its simplest incarnation, without the nodes parameter and with an arg_count parameter of 0. This is fine when making deferred calls to procedures that take no parameters, and when the default destinations are acceptable, but sooner or later you will want to defer calls to procedures that require parameters, and you will want to specify the destinations for each call individually. The steps to accomplish these more complex operations follow: 1. Specify the destination nodes, either with DBMS_CALL.TRANSACTION or by supplying the nodes parameter to DBMS_DEFER.CALL. 2. Execute DBMS_DEFER.CALL, supplying the schema name, package name, procedure name, number of arguments to the procedure, and (if you do not use DBMS_CALL.TRANSACTION) the nodes parameter. 3. Call DBMS_DEFER.<datatype>_arg arg_count times, where arg_count is the value passed to DBMS_DEFER.CALL. The order in which you call DBMS_DEFER.<datatype>_arg must be the same order as the parameters are listed in the procedure definition. 4. Call DBMS_DEFER.COMMIT_WORK with an optional comment. 17.3.3.1 The DBMS_DEFER.<datatype>_ARG procedure This procedure specifies an argument for a deferred call. The argument is of the datatype specified in <datatype>. Here is the specification: PROCEDURE DBMS_DEFER.<datatype>ARG (arg IN <datatype>. specifications differ for different datatypes, depending on whether you are using Oracle7 or Oracle8. [Appendix A] What's on the Companion Disk? 17.3.2 Basic RPCs 793 <datatype> can be one of the following: NUMBER DATE VARCHAR2 CHAR ROWID RAW NVARCHAR2 (Oracle8 only) ANY_VARCHAR2 (Oracle8 only) NCHAR (Oracle8 only) ANY_CHAR (Oracle8 only) BLOB (Oracle8 only) CLOB (Oracle8 only) ANY_CLOB (Oracle8 only) NCLOB (Oracle8 only) The arg parameter is the value to pass to the parameter of the same datatype in the procedure previously queued via DBMS_DEFER.CALL. The various alternatives are listed here. The following specifications apply to both Oracle7 and Oracle8: PROCEDURE NUMBER_ARG (arg IN NUMBER); PROCEDURE DATE_ARG (arg IN DATE); PROCEDURE VARCHAR2_ARG (arg IN VARCHAR2); PROCEDURE CHAR_ARG (arg IN CHAR); PROCEDURE ROWID_ARG (arg IN ROWID); PROCEDURE RAW_ARG (arg IN raw); These specifications apply only to Oracle8: PROCEDURE NVARCHAR2_ARG (arg IN NVARCHAR2); PROCEDURE ANY_VARCHAR2_ARG (arg IN VARCHAR2 CHARACTER SET ANY_CS); PROCEDURE NCHAR_ARG (arg IN NCHAR); PROCEDURE ANY_CHAR_ARG (arg IN CHAR CHARACTER SET ANY_CS); PROCEDURE BLOB_ARG (arg IN BLOB); PROCEDURE CLOB_ARG (arg IN CLOB); PROCEDURE ANY_CLOB_ARG (arg IN CLOB CHARACTER SET ANY_CS); PROCEDURE NCLOB_ARG (arg IN NCLOB); 17.3.3.1.1 Exceptions This procedure may raise the following exception: Name Number Description paramlen_num −23323 Parameter is too long 17.3.3.1.2 Example The following scenario describes how to perform the steps required to construct a deferred RPC that takes parameters. Suppose that we have a PRODUCTS table and a procedure that adds new products to it, as follows: [Appendix A] What's on the Companion Disk? 17.3.3 Parameterized RPCs 794 SQL> desc products Name Null? Type −−−−−−−−−−−−−−−−−−− −−−−−−−− −−−− PRODUCT_ID NOT NULL NUMBER(9) PRODUCT_TYPE NOT NULL NUMBER(6) CATALOG_ID NOT NULL VARCHAR2(15) DESCRIPTION NOT NULL VARCHAR2(30) REV_LEVEL NOT NULL VARCHAR2(15) PRODUCTION_DATE NOT NULL DATE PRODUCTION_STATUS NOT NULL VARCHAR2(10) AUDIT_DATE NOT NULL DATE AUDIT_USER NOT NULL VARCHAR2(30) GLOBAL_NAME NOT NULL VARCHAR2(20) Procedure ProductMaint.AddProduct populates this table. We will queue deferred calls to the this procedure. CREATE OR REPLACE PACKAGE ProductMaint IS PROCEDURE AddProduct(product_type_ININ NUMBER, catalog_id_IN IN VARCHAR2, description_IN IN VARCHAR2, rev_level_IN IN VARCHAR2, production_date_ININ DATE, product_status_ININ VARCHAR); END ProductMaint; / CREATE OR REPLACE PACKAGE BODY ProductMaint IS PROCEDURE AddProduct(product_type_ININ NUMBER, catalog_id_IN IN VARCHAR2, description_IN IN VARCHAR2, rev_level_IN IN VARCHAR2, production_date_IN IN DATE, product_status_IN IN VARCHAR) IS BEGIN INSERT INTO products (product_id, product_type, catalog_id, description, rev_level, production_date, production_status, audit_date, audit_user, global_name ) VALUES (seq_products.nextval, product_type_IN, catalog_id_IN, description_IN, rev_level_IN, production_date_IN, product_status_IN, SYSDATE, USER, DBMS_REPUTIL.GLOBAL_NAME); END AddProduct; END ProductMaint; Since the procedure ProductMaint.AddProduct accepts parameters, we must supply values for these parameters when building a deferred call. The following procedure does just that: CREATE OR REPLACE PROCEDURE qAddProduct IS vNodes DBMS_DEFER.NODE_LIST_T; BEGIN [Appendix A] What's on the Companion Disk? 17.3.3 Parameterized RPCs 795 . following: NUMBER DATE VARCHAR2 CHAR ROWID RAW NVARCHAR2 (Oracle8 only) ANY_VARCHAR2 (Oracle8 only) NCHAR (Oracle8 only) ANY_CHAR (Oracle8 only) BLOB (Oracle8 only) CLOB (Oracle8 only) ANY_CLOB (Oracle8 only) NCLOB (Oracle8 only) The arg parameter. using Oracle7 or Oracle8 . [Appendix A] What's on the Companion Disk? 17.3.2 Basic RPCs 793 <datatype> can be one of the following: NUMBER DATE VARCHAR2 CHAR ROWID RAW NVARCHAR2 (Oracle8 . DBMS_DEFER.CALL. The various alternatives are listed here. The following specifications apply to both Oracle7 and Oracle8 : PROCEDURE NUMBER_ARG (arg IN NUMBER); PROCEDURE DATE_ARG (arg IN DATE); PROCEDURE