1. Database Programming
Sections 7 & 8 – Data Manipulation Language (DML) transaction, INSERT, implicit, explicit, USER, UPDATE, DELETE, integrity constraint, DDL commands
10/3/06 – updated 11/3/09 DPLesson7_8_Fa09

2. Overview of remainder of lesson
Data Manipulation Language DML
INSERT
UPDATE
DELETE
MERGE
Default Values
Merge Statements
Creating Tables
Using Data Types
Data Definition Language DDL
ALTER TABLE
DROP TABLE
RENAME
TRUNCATE
COMMENT
Define Constraints
Manage Constraints
Managing Constraints is in Chapter 9
Chapter 7 is DML
Chapter 8 is DDL
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3. Using a subquery to copy a table
In order to experiment with the tables, make a copy of them: Select all rows from the EMPLOYEES table and insert them into the COPY_EMPLOYEES table.
CREATE TABLE copy_employees AS (SELECT * FROM employees);
Verify by: SELECT * FROM copy_employees;
DESCRIBE copy_employees;
the integrity rules (primary keys, default values are not passed to the copy, only the column datatype definitions.)
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4. Explicitly inserting data
Executing one DML statement is considered a transaction.
The INSERT statement is used to add new rows to a table. To get the column names and default order, use:
The statement requires three values:
the name of the table
the name of the column in the table to populate
a corresponding value for the column –
INSERT INTO copy_departments (department_id, department_name, manager_id, location_id) VALUES (70,’Public Relations’, 100, 1700);
INSERT INTO copy_departments (department_id, manager_id, location_id, department_name) VALUES (99, 100, 1700, ‘Advertising’)
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5. Implicitly inserting data
Omit the column names
Match exactly the default order in which columns appear in the table
Provide a value for each column
Data types need to match
Use DESCRIBE to check the table structure before adding is a good idea
INSERT INTO copy_departments VALUES (100,’Education’, 100, 1700);
using VALUES adds on row at a time
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6. Insert with NULL values
Implicit Method – omit the column from the column list
Any column that is not listed obtains a null value in the new row – errors can occur – the row has been specified NOT NULL, uniqueness, foreign key violation
INSERT INTO copy_departments (department_id, department_name) VALUES (30,’Purchasing’);
Explicit Method – specify the NULL keyword in the values clause
INSERT INTO copy_departments VALUES (100, ‘Finance’, NULL, NULL);
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7. Inserting Special Values
Special values such as SYSDATE and USER can be entered in the VALUES list of an INSERT statement.
SYSDATE puts current date and time in a column
USER places current username (Oracle Application Express will put APEX_PUBLIC_USER)
INSERT INTO copy_employees (employee_id, last_name, , hire_date,job_id) VALUES(1001, USER, ‘Test’, SYSDATE, ‘IT_PROG’);
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8. Inserting Special Values
Can add functions and calculated expressions as values
Example of inserting a system date and a calculated expression
INSERT INTO copy_f_orders (order_number, order_date, order_total ,cust_id, staff_id) VALUES (1889,SYSDATE,87.92*1.08,123,19);
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9. Inserting Specific date values
The default date before Oracle 9i was DD-MON-YY.
The default format for Oracle 9i is DD-MON-RR
century defaults to the current century
default time of midnight (00:00:00)
formats other than the default format use TO_DATE function
INSERT INTO copy_employees VALUES (114, ‘Den’, ‘Raphealy’, ‘DRAPHEAL’, ‘ ’, ’03-FEB-49’, ‘AC_ACCOUNT’, 11000, NULL, 100, 30);
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10. Inserting Date values The default format model for date is DD-MON-RR.
Recall the century defaults to the nearest century (nearest to SYSDATE) with default time midnight (00:00:00)
TO_CHAR review: SELECT first_name, TO_CHAR(birthdate, ‘Month fmDD, RRRR’) FROM f_staffs WHERE id=12;
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11. Inserting Date values
To INSERT a row with a non-defaut format for a date column, use the TO_DATE function to convert the date value (a character string ) to a date
INSERT INTO copy_f_staffs (first_name, last_name, TO_DATE(birthdate, ‘Month fmDD, RRRR’), salary, staff_type) VALUES (‘Sue’, ‘Jones’, ’July 1, 1980’, 25,
‘clerk’);
Check
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12. Date Example
INSERT INTO copy_employees VALUES (114, ‘Den’, ‘Raphealy’, ‘DRAPHEAL’, ‘ ’, ’03-FEB-49’, ‘AC_ACCOUNT’, 11000, NULL, 100, 30);
SELECT last_name, TO_CHAR(hire_date, ’Month dd, RRRR’) FROM copy_employees WHERE employee_id = 114;
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13. Example
INSERT INTO copy_f_staffs (first_name, salary, staff_type, TO_DATE(birthdate, 'Month fmDD, RRRR HH24:MI‘) VALUES ('Sue', null, null, 'July 1, :20');
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14. Inserting multiple rows
INSERT statement can be used to insert one row, but to insert multiple rows use a subquery
Use a subquery within the INSERT command to insert multiple rows
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16. Using a subquery to copy rows
Copy values from an existing table CREATE TABLE sales_reps (id number(5), name varchar2(15), salary number(10), commission_pct number (8));
No VALUES clause INSERT INTO sales_reps(id, name, salary, commission_pct) SELECT employee_id, last_name, salary, commission_pct FROM employees WHERE job_id LIKE ‘%REP%’;
NOTE: subquery is not in parentheses as in WHERE clause previously
the number of rows and data types MUST match the fields within the table. This should add 4 rows into the table.
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17. Copy all the data from a table
INSERT INTO sales_reps SELECT * FROM employees;
This works ONLY if both tables have same number of columns, same types, and in the same order.
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18. UPDATE statements
The UPDATE statement is used to modify existing rows in a table. It requires four values:
the name of the table
UPDATE copy_employees
the name of the column in the table to populate
SET department_id
a corresponding value or subquery for the column
SET department_id = 70
a condition that identifies the columns and the changes for each column
WHERE employee_id = 103;
New value can be from a single-row subquery
Section 7 Lesson 2
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19. Updating one column
Specific row or rows are modified if you specify the WHERE clause.
UPDATE copy_employees SET department_id = 70 WHERE employee_id = 103; (One row is updated)
WARNING: All rows in the table are modified if you omit the WHERE clause.
UPDATE copy_employees SET department_id = 110; (All rows are updated)
UPDATE copy_f_customers
SET phone_number=‘ ’
WHERE id=123;
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20. UPDATING multiple columns
Can update one or more rows in a statement
UPDATE copy_f_customers SET phone_number = ‘ ’, city = ‘Chicago’ WHERE id<200;
If no WHERE clause all rows are updated in the table
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21. Update using subquery
UPDATE copy_employees SET department_id = (SELECT department_id FROM employees WHERE last_name = ‘Ernst’) WHERE employee_id = 103;
UPDATE copy_f_staffs SET salary = (SELECT salary FROM copy_f_staffs WHERE id=19)
WHERE id = 12;
In slide may need to have employee_id = 113
Change to 60 from 70 (original department)
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22. Updating columns with subqueries
You can update one or more columns in the SET clause of an UPDATE statement by writing subqueries.
UPDATE copy_employees SET job_id = (SELECT job_id FROM employees WHERE employee_id =205) salary = (SELECT salary FROM employees WHERE employee_id =205) WHERE employee_id = 114;
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23. Updating rows based on another table
Use a subquery to update data in one table with data in another table
UPDATE copy_f_staffs SET salary = (SELECT salary FROM f_staffs WHERE id = 9) WHERE id = 9;
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24. Integrity Constraints
Integrity constraints define certain data quality requirements that the data in the database needs to meet. If a user tries to insert data that doesn’t meet these requirements an error will occur.
Types of Integrity constraints
NOT NULL – each row in the column must have a value
PRIMARY KEY – unique and not null
FOREIGN KEY – A foreign key constraint (also called referential integrity constraint) on a column ensures that the value in that column is found in the primary key of another table.
CHECK – value meets certain conditions salary CHECK < 50000
UNIQUE – no duplicate values in a column ( address)
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25. Integrity Constraint Errors
UPDATE employees SET department_id = 55 WHERE department_id = 110;
ORA-02291: integrity constraint (USCA_INST_SQL03_T01.EMP_DEPT_FK) violated – parent key not found
There is no department_id = 55 in the departments table which is the parent table
UPDATE copy_f_staffs SET first_name = (SELECT first_name FROM copy_f_staffs WHERE id=123);
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26. DELETE statement
The DELETE statement is used to remove existing rows in a table. The statement requires two values:
the name of the table
the condition that identifies the rows to be deleted DELETE FROM copy_employees WHERE employee_id = 200;
If you omit the WHERE clause all rows will be deleted
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27. Subquery Delete
Use subqueries in DELETE statements to remove rows from a table based on values from another table.
DELETE FROM copy_employees WHERE department_id = (SELECT department_id FROM departments WHERE department_name = ‘Shipping’);
WHERE department_name = ‘Shipping’
WHERE department_name LIKE ‘%REP%’
WHERE department_name LIKE ‘%Sal%’
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28. Deleting rows based on another table
A subquery can be used to remove rows from one table based on values from another table
DELETE FROM emp WHERE plant_id = (SELECT plant_id FROM locations WHERE plant_loc = ‘AnyVilla’);
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29. Default Values A column in a table can be given a default value.
Assigning default values prevents null values from existing in the column.
Default values can be:
a literal value, ‘no commission assigned’
an expression, salary*1.15
SQL function, such as SYSDATE or USER
Default values must match the data type of the column
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30. Default Values Examples
Default Values Specified at the time the table is created: CREATE TABLE items( part_number VARCHAR2(10), description VARCHAR2(10), qty_on_hand NUMBER DEFAULT 0);
INSERT INTO items(part_number, description) VALUES (‘AB154’,’hammer’);
CREATE TABLE my_employees( hire_date DATE DEFAULT SYSDATE,
first_name VARCHAR2(15),
last_name VARCHAR2(15));
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31. Default Values - Examples
Use DEFAULT when inserting values:
INSERT INTO items(part_number, description, qty_on_hand) VALUES (300,’Widget’, DEFAULT);
Use DEFAULT when updating values:
UPDATE items SET qty_on_hand = DEFAULT WHERE part_number = 200;
Now check the results!
SELECT * FROM items;
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33. MERGE Statements MERGE Statement
Accomplishes an UPDATE and INSERT at the same time ** the ON clause specifies the match – if two id’s match make the following updates, otherwise insert the following as new rows
MERGE INTO copy_emp c USING employees e ON (c.employee_id = e.employee_id) WHEN MATCH THEN UPDATE SET c.first_name = e.first_name c.last_name = e.last_name c.department_id = e.department_id WHEN NOT MATCHED THEN INSERT VALUES( e.employee_id, e.first_name, e.last_name, e.salary, e.commission_pct, e.manager_id, e.department_id);
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34. MERGE Example:
MERGE INTO copy_items c USING items i ON(c.part_number = i.part_number) WHEN MATCHED THEN UPDATE SET c.description = i.description c.qty_on_hand = i.qty_on_hand WHEN NOT MATCHED THEN INSERT VALUES (i.part_number, i.description, i.qty_on_hand);
UPDATE copy_employees
SET first_name = ‘Sue’
WHERE employee_id = ‘100’;
MERGE INTO copy_employees c USING employees e
ON(c.employee_id=e.employee_id)
WHEN MATCHED THEN UPDATE
SET
c.last_name = e.last_name,
c.first_name = e.first_name,
c.department_id = e.department_id
WHEN NOT MATCHED THEN INSERT
VALUES (e.employee_id, e.first_name,e.last_name,e. ,e.phone_number,e.hire_date,e.job_id,e.salary,e.commission_pct,e.manager_id,e.department_id);
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35. CREATING TABLES Naming Rules: Must begin with a letter
Must be 1 to 30 characters in length
Must only contain alpha/numeric,_,$,#
Must be unique in your schema
Must not be an Oracle Server reserved word
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36. Using Data Types Most Common Data Types: VARCHAR2 NUMBER DATE
Examples: Name, Address
NUMBER
Examples: Price, Quatity
DATE
Examples: DOB, Hire Date
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37. Creating Tables
CREATE TABLE name (column name DATATYPE(specifications for datatype)
VARCHAR2(number of characters) – variable length data
CHAR(size) – fixed length data
NUMBER(precision, scale) – total number of decimal digits(1 to 38), right of decimal digits(-84 to 127) For example, a scale of 2 means the value is rounded to the nearest hundredth (3.456 becomes 3.46); a scale of -3 means the number is rounded to the nearest thousand (3456 becomes 3000).
DATE – date and time
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38. Creating Tables cont’d
Example: CREATE TABLE students (id VARCHAR2(5), lname VARCHAR2(15), fname VARCHAR2(15), GPA number(6), enroll_date date DEFAULT SYSDATE);
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41. ORACLE Data Dictionary
The data dictionary is a collection of tables created and maintained by the Oracle Server and contains information about the database.
All data dictionary tables are owned by the SYS user. Because the tables are difficult to understand, users access data dictionary includes names of the Oracle Server users, privileges granted to users, database object names, table constrains and auditing information.
You may browse the Oracle Data Dictionary to show objects you own.
SELECT * FROM DICTIONARY; - returns 610 items
SELECT table_name FROM user_tables;
SELECT DISTINCT object_type FROM user_objects;
SELECT * FROM user_catalog;
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42. Using Data Types – Interval Year to Month
INTERVAL YEAR TO MONTH: Stores a period of time in years/months Note that the argument 3 in the create table and insert statements refers to precision
CREATE TABLE time_ex2 (school_year_duration INTERVAL YEAR (3) TO MONTH);
INSERT INTO time_ex2(school_year_duration) VALUES(INTERVAL ‘9’ Month(3));
SELECT TO_CHAR(SYSDATE + school_year_duration, ‘dd-Mon-yyyy’) FROM time_ex2;
Returned 9 month from today’s date
Insert the outcome in slide
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43. Using Data Types- USING INTERVAL DAY TO SECOND
INTERVAL DAY TO SECOND: Stores a more precise period of time (days/hours/minutes/seconds)
CREATE TABLE time_ex3(day_duration INTERVAL DAY(3) to SECOND);
INSERT INTO time_ex3(day_duration) VALUES(INTERVAL ‘180’ DAY(3));
SELECT SYSDATE + day_duration “Half Year” FROM time_ex3;
Insert results for slide.
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44. Using Time Data Types
TIMESTAMP: stores values with respect to universal time
CREATE TABLE time_example (order_date TIMESTAMP WITH LOCAL TIME ZONE, ship_date DATE DEFAULT SYSDATE);
INSERT INTO time_example VALUES(SYSDATE, SYSDATE);
SELECT * FROM time_example;
Insert the results at end of slide.
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52. Sect 7 Less. 2 #16
Try these
UPDATE employees
SET department_id = 15
WHERE employee_id = 100;
DELETE FROM department
WHERE department_id = 10;
SET department_id = 10
WHERE department_id = 20;
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