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Creating Procedures/Dbms_sql/Dbms_job/Triggers


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Creating Procedures/Dbms_sql/Dbms_job/Triggers

  1. 1. Anar Godjaev Creating Procedures/Dbms_sql/Dbms_job/Triggers Subprograms A procedure that performs an action A function that computes a value A package bring them all together Note: use “show errors” to view compilation errors in sqlplus EX: Create or replace procedure raise_salary ( p_id number, p_amount number, p_id out employees.employee_id%TYPE ) as -- declaration section begin update employees set salary = salary + (salary * 0.20) end raise_salary; execute raise_salary (101,5000) passing in/out parameters: -- sqlplus create or replace procedure query_emp (p_id in employees.employee_id%TYPE, p_name out employees.last_name%TYPE, p_salary out employees.salary%TYPE, p_comm out employees.employee_pct%TYPE) is -- declare local variables here begin select last_name , salary , commision_pct into p_name, p_salary, p_comm from employees where employee_id = p_id; end query_emp; / variable g_name varchar2(25) variable g_sal number variable g_comm number execute query_emp (171, :g_name, :g_sal, :g_comm) print g_name EX: create or replace procedure p_name (arg1 number default 100, arg2 varchar2 default „TTTT‟) is -- local declaration begin
  2. 2. Anar Godjaev null; exception when others then null; end; p_name (arg1 => 50, arg2 => „ANAR‟); drop procedure procedure_name; EX: CREATE OR REPLACE FUNCTION function_name RETURN NUMBER IS tmpVar NUMBER; BEGIN tmpVar := 0; RETURN tmpVar; EXCEPTION WHEN NO_DATA_FOUND THEN NULL; WHEN OTHERS THEN -- Consider logging the error and then re-raise RAISE; END function_name; Oracle Supplied Packages: DBMS_SQL Open_cursor: Parse: open a cursor and assign an id parse a ddl or dml statement Check the syntax and associate it with the opened cursor (DDL statements are immediately executed when parsed) bind_variable: binds the given value to the variable identified by its name in the parsed statement in the open cursor execute: executes the sql statement and returns the number of rows affected fetch_rows: retrieves a row for the sepicified cursor close_cursor: closes the specified cursor EX: -- sqlplus create or replace procedure delete_all_rows (p_tab_name in varchar2, p_rows_del out number) is cursor_name integer; begin cursor_name := dbms_sql.open_cursor; dbms_sql.parse (cursor_name, „Delete from „ || p_rab_name , dbms_sql.native);
  3. 3. Anar Godjaev p_rows_Del := dbms_Sql.execute(cursor_name); dbms_sql.close_cursor(cursor_name) ; end; / variable delete_number number; execute delete_all_rows („employees‟, :deleted); print delete_number; execute immediate „delete from ‟ || p_table_name; p_rows_deleted := sql%rowcount; DBMS_JOB: Submit: Remove: Change: to the queue What: Next_date: İnterval: Broken: Run: submits a job to the job queue removes a specified job from the queue alters a specified job that has already been submitted alters the job description alters the next execution time for the specified job alters the interval between executions for a job disable kob execution force a job to run EX: -- sqlplus variable job_no number begin dbms_job.submit ( job => :job_no, what => „over_pack.add_dept (“education”,2710);‟, next_Date => trunc(sysdate+1), interval => „trunc(sysdate+1)‟ ; commit; end; / print job_no; dbms_job.change (job_no, null, trunc(sysdate+1)+6/24, „sysdate+4/24‟); dbms_job.remove(job_no) dbms_job.broken(job_no) select * from user_jobs; Triggers: create or replace trigger secure_emp
  4. 4. Anar Godjaev before insert or delete or update on employees begin if (to_char(sysdate, „dy‟) in („sat‟,‟sun‟) or to_char(sysdate,‟hh24‟) not between „08‟ and „18‟) then if DELETING then raise_application_error (-20502,‟ ... ‟) elseif INSERTING then raise_application_error (-20503,‟ ... ‟) elseif UPDATING then raise_application_error (-20504,‟ ... ‟) end if ; end if ; end secure_emp; create or replace trigger secure_emp after insert or delete or update on employees for each row begin insert into audit_emp_table (...) values (:OLD.lastname, :NEW.lastname) end; / create or replace trigger derive_comission_pct before insert or update of salary on employees for each row where (new.job_id = „sa_rep‟) begin if inserting then :NEW.comission_pct := 0; elsif :OLD.comission_pct is null then :NEW.comission_pct := 0; else :NEW.comission_pct :=OLD.comission_pct + 0.05; end if; end; / create or replace trigger logon_trig after logon on schema begin insert into log_trig_table (user_id, lodate, action) values (user, sysdate, „logging on‟); end; /