Interacting with Oracle Database

Interacting with Oracle Database
Server:
SQL Statements in PL/SQL Programs

SELECT Statements in PL/SQL
• SELECT select_list INTO {variable_name[, variable_name]... | record_name}
FROM table [WHERE condition];
• Use the SELECT statement to retrieve data from the database.
– select_list: List of at least one column; can include SQL expressions, row
functions, or group functions
– variable_name: Scalar variable that holds the retrieved value
– record_name:PL/SQL record that holds the retrieved values
– Table: Specifies the database table name
– Condition:
• Ex1:
DECLARE
v_fname VARCHAR2(25);
BEGIN
SELECT custName INTO v_fname
FROM tbCustomer WHERE custID=2;
DBMS_OUTPUT.PUT_LINE(' cust name is : '||v_fname);
END;

SELECT Statements in PL/SQL
• EX1:
SELECT EMPID, EMPNAME,GENDER,ADDRESS,DOB,SSID
FROM TBEMPLOYEE;
• EX:SELECT DISTINCT ADDRESS FROM TBEMPLOYEE;
• Ex2:
DECLARE
empName TBEMPLOYEE.EMPNAME%TYPE;
empDob TBEMPLOYEE.DOB%TYPE;
empSalary TBEMPLOYEE.SALARY%TYPE;
BEGIN
SELECT EMPNAME,dob, salary
INTO empName,empDob, empSalary
FROM TBEMPLOYEE
WHERE EMPNAME = 'Chan Da' AND GENDER='Male' AND Address='Phnom Penh';
DBMS_OUTPUT.PUT_LINE ('Name is :'|| empName);
DBMS_OUTPUT.PUT_LINE ('Salary is :'|| empSalary);
DBMS_OUTPUT.PUT_LINE ('DOB is :'|| empDob);
END;

Manipulating data with PL/SQL
• Make changes to database tables by using DML commands:
• The INSERT statement adds new rows to the table.
• The UPDATE statement modifies existing rows in the table.
• The DELETE statement removes rows from the table.
• The MERGE statement selects rows from one table to update or insert into another
table.
• EX1:
BEGIN
INSERT INTO employees
(employee_id, first_name, last_name, email,hire_date, job_id, salary)
VALUES(employees_seq.NEXTVAL, 'Ruth', 'Cores','RCORES',CURRENT_DATE, 'AD_ASST',
4000);
END;
EX2:
BEGIN
INSERT INTO TBEMPLOYEE(EMPID,EMPNAME,GENDER, ADDRESS,DOB,SSID,SALARY)
VALUES(4, 'Ruth', 'FEMALE','PHNOM PENH','1-JAN-1979', '112233',123);
END;

• EX2: Update
DECLARE
sal_increase employees.salary%TYPE := 800;
BEGIN
UPDATE employees
SET salary = salary + sal_increase
WHERE job_id = 'ST_CLERK';
END;
• Ex3:
DECLARE
GENDER_V TBEMPLOYEE.GENDER%TYPE := 'FEMALE';
BEGIN
UPDATE TBEMPLOYEE SET GENDER=GENDER_V WHERE EMPID=4;
END;
• EX3:Delete
DECLARE
deptno employees.department_id%TYPE := 10;
BEGIN
DELETE FROM employees
WHERE department_id = deptno;
END;
EX4:
DECLARE
GENDER_VAR VARCHAR2(20) :='MALE';
BEGIN
DELETE FROM TBEMPLOYEE WHERE
GENDER=GENDER_VAR;
END;

• Syntax: Merge
BEGIN
MERGE INTO copy_emp c
USING employees e
ON (e.employee_id = c.empno)
WHEN MATCHED THEN
UPDATE SET
c.first_name = e.first_name,
c.last_name = e.last_name,
c.email = e.email,
. . .
WHEN NOT MATCHED THEN
INSERT VALUES(e.employee_id, e.first_name, e.last_name,
. . .,e.department_id);
END;

• EX4: Merge
BEGIN
USING employees e
WHEN MATCHED THEN
UPDATE SET
c.email = e.email,
c.phone_number = e.phone_number,
c.hire_date = e.hire_date,
c.job_id = e.job_id,
c.salary = e.salary,
c.commission_pct = e.commission_pct,
c.manager_id = e.manager_id,
c.department_id = e.department_id
INSERT VALUES(e.employee_id,
e.first_name, e.last_name,
e.email, e.phone_number, e.hire_date,
e.job_id,
e.salary, e.commission_pct, e.manager_id,
e.department_id);
END;

• EX5:
BEGIN
MERGE INTO TBEMPLOYEEBACK c
USING TBEMPLOYEE e
ON (e.EMPID = c.EMPID)
WHEN MATCHED THEN
UPDATE SET
c.EMPNAME = e.EMPNAME,
c.GENDER = e.GENDER,
c.ADDRESS = e.ADDRESS,
c.DOB = e.DOB,
c.SSID = e.SSID,
c.SALARY= e.SALARY
INSERT VALUES(e.EMPID, e.EMPNAME, e.GENDER,
e.ADDRESS, e.DOB, e.SSID, e.SALARY);
END;
EX6:
MERGE INTO bonuses D USING (SELECT
employee_id, salary, department_id FROM
employees WHERE department_id = 80) S
ON (D.employee_id = S.employee_id)
WHEN MATCHED THEN UPDATE SET
D.bonus = D.bonus + S.salary*.01 DELETE
WHERE (S.salary > 8000) WHEN NOT
MATCHED THEN INSERT (D.employee_id,
D.bonus) VALUES (S.employee_id,
S.salary*0.1) WHERE (S.salary <= 8000);

Table Relationship
• In SQL Developer, go to View > Data Modeler > Browser. In the Browser view
right click on Relational Models and create a new one. This should create a new
blank diagram. You can drag and drop tables from the Connection view into the
diagram.
• ALTER TABLE TBPRODUCTS ADD
CONSTRAINT FK_PRODUCT_CATE_NUM
FOREIGN KEY (CATEID) REFERENCES TBCATEGORY(CATEID);
• ALTER TABLE TBSALE ADD
CONSTRAINT FK_SALE_CUSTOMER_NUM
FOREIGN KEY (CUSTID)
REFERENCES TBCUSTOMER(CUSTID);

Or using wizard by sql developer

JOIN operations
• The JOIN operations, which are among the possible TableExpressions in a FROM clause,
perform joins between two tables.
1. INNER JOIN operation: Specifies a join between two tables with an explicit join clause.
SYNTAX:
TableExpression [ INNER ] JOIN
TableExpression { ON booleanExpression | USING clause }
EX1:
SELECT *
FROM TBPRODUCTS INNER JOIN
TBCATEGORY ON
TBPRODUCTS.CATEID = TBCATEGORY.CATEID;
EX2:
SELECT * FROM SAMP.EMPLOYEE
INNER JOIN SAMP.STAFF ON
EMPLOYEE.SALARY < STAFF.SALARY
EX6:
MERGE INTO bonuses D USING (SELECT
employee_id, salary, department_id FROM
employees WHERE department_id = 80) S
ON (D.employee_id = S.employee_id)
WHEN MATCHED THEN UPDATE SET
D.bonus = D.bonus + S.salary*.01 DELETE
WHERE (S.salary > 8000) WHEN NOT
MATCHED THEN INSERT (D.employee_id,
D.bonus) VALUES (S.employee_id,
S.salary*0.1) WHERE (S.salary <= 8000);

JOIN operations
• Oracle JOINS are used to retrieve data from multiple tables. An Oracle JOIN is
performed whenever two or more tables are joined in a SQL statement.
• There are 4 different types of Oracle joins:
– Oracle INNER JOIN (or sometimes called simple join)
– Oracle LEFT OUTER JOIN (or sometimes called LEFT JOIN)
– Oracle RIGHT OUTER JOIN (or sometimes called RIGHT JOIN)
– Oracle FULL OUTER JOIN (or sometimes called FULL JOIN)
• INNER JOIN (SIMPLE JOIN)
• Oracle INNER JOINS return all rows from multiple tables where the join condition is
met. Syntax
– SELECT columns FROM table1 INNER JOIN table2 ON table1.column =
table2.column;
Ex1:
SELECT suppliers.supplier_id,
suppliers.supplier_name, orders.order_date
FROM suppliers INNER JOIN orders ON
suppliers.supplier_id = orders.supplier_id;

JOIN operations
• Old Syntax
– older implicit syntax as follows (but we still recommend using the INNER JOIN
keyword syntax):
– SELECT suppliers.supplier_id, suppliers.supplier_name, orders.order_date FROM
suppliers, orders WHERE suppliers.supplier_id = orders.supplier_id;

JOIN operations
• LEFT OUTER JOIN
– This type of join returns all rows from the LEFT-hand table specified in the ON
condition and only those rows from the other table where the joined fields are
equal (join condition is met).
• Syntax: Oracle LEFT OUTER JOIN is:
• SELECT columns FROM table1 LEFT [OUTER] JOIN table2
ON table1.column = table2.column;
• Ex1:
– SELECT suppliers.supplier_id, suppliers.supplier_name, orders.order_date FROM
suppliers LEFT OUTER JOIN orders ON suppliers.supplier_id = orders.supplier_id;
• Old Syntax
– LEFT OUTER JOIN example above
could be rewritten using the older
implicit syntax that utilizes the outer
join operator (+) as follows
(but we still recommend using the LEFT OUTER JOIN
keyword syntax):
SELECT suppliers.supplier_id, suppliers.supplier_name,
orders.order_date FROM suppliers, orders WHERE suppliers.supplier_id = orders.supplier_id(+);

JOIN operations
• Right join returns all rows from the RIGHT-hand table specified in the ON condition
and only those rows from the other table where the joined fields are equal (join
condition is met).
• Syntax
• SELECT columns FROM table1 RIGHT [OUTER] JOIN table2 ON table1.column =
table2.column;
EX:
SELECT orders.order_id, orders.order_date,
suppliers.supplier_name FROM suppliers RIGHT
OUTER JOIN orders ON suppliers.supplier_id =
orders.supplier_id;
Old Syntax:utilizes the outer join operator (+) as follows (but we still
recommend using the RIGHT OUTER JOIN keyword syntax):
SELECT orders.order_id, orders.order_date, suppliers.supplier_name
FROM suppliers, orders WHERE suppliers.supplier_id(+) =
orders.supplier_id;

JOIN operations
• FULL OUTER JOIN
• returns all rows from the LEFT-hand table and RIGHT-hand table with nulls in place
where the join condition is not met.
• Syntax
• SELECT columns FROM table1 FULL [OUTER] JOIN table2 ON table1.column =
table2.column;
Ex:
SELECT suppliers.supplier_id, suppliers.supplier_name,
orders.order_date FROM suppliers FULL OUTER JOIN
orders ON suppliers.supplier_id = orders.supplier_id;

Introducing SQL cursors
• EX4: Merge
BEGIN
USING employees e
WHEN MATCHED THEN
UPDATE SET
c.email = e.email,
c.phone_number = e.phone_number,
c.hire_date = e.hire_date,
c.job_id = e.job_id,
c.salary = e.salary,
c.commission_pct = e.commission_pct,
c.manager_id = e.manager_id,
c.department_id = e.department_id

Interacting with Oracle Database

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