Introduction to-sql

Contents ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Contents (2) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Contents (3) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Relational Databases Short Overview

Relational Database Concepts ,[object Object],[object Object],[object Object],[object Object]

Definition of a Database ,[object Object],Database Table Name: EMPLOYEES Table Name: DEPARTMENTS ZZZ Alexiev Danail 102 YYY Spasov Rosen 101 XXX Nakov Svetlin 100 EMAIL LAST_NAME FIRST_NAME EMPLOYEE_ID 124 Finances 50 201 Sales 20 200 IT 10 MANAGER_ID DEPARTMENT_NAME DEPARTMENT_ID

Data Models Model of system in client's mind Table model of entity model Entity model of client's model Database

Entity Relationship Model ,[object Object],[object Object],[object Object],[object Object],EMPLOYEE #* number * name o job title DEPARTMENT #* number * name o location assigned to composed of

Relating Multiple Tables ,[object Object],[object Object],Table Name: EMPLOYEES Table Name: DEPARTMENTS Primary key Foreign key Primary key 90 Alexiev Danail 102 50 Spasov Rosen 101 80 Nakov Svetlin 100 DEPARTMENT_ID LAST_NAME FIRST_NAME EMPLOYEE_ID Finances 50 Sales 20 IT 10 DEPARTMENT_NAME DEPARTMENT_ID

Database Terminology Table Name: EMPLOYEES Row Primary key column Column Foreign key column Null value Field 90 Alexiev Danail 102 60 9000 Ivanov Radoslav 10 3 6000 17000 24000 SALARY 90 Spasov Rosen 10 4 50 Nachev Miroslav 101 80 Stoynov Mihail 100 DEPARTMENT_ID LAST_NAME FIRST_NAME EMPLOYEE_ID

Relational Databases ,[object Object],[object Object],[object Object],[object Object],[object Object]

Communicating with a DB SQL statement is sent to the database SQL statement is entered SELECT department_name FROM departments The result is returned (usually as a table) Database Finances Sales IT DEPARTMENT_NAME

The Structured Query Language (SQL) Introduction

What is SQL? ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Entity Relationship (E/R) Diagrams The HR Database Schema in Oracle Express

The HR Database Schema in Oracle 10g

SQL Language Introducing SELECT Statement

Capabilities of SQL SELECT Table 1 Table 2 Table 1 Table 1 Selection Take some of the rows Projection Take some of the columns Join Combine tables by some column

Basic SELECT Statement ,[object Object],[object Object],SELECT *|{[DISTINCT] column|expression [alias],...} FROM table

SELECT Example ,[object Object],[object Object],SELECT * FROM DEPARTMENTS SELECT DEPARTMENT_ID, LOCATION_ID FROM DEPARTMENTS 124 201 200 MANAGER_ID 1900 Shipping 50 1800 Marketing 20 1700 Administration 10 LOCATION_ID DEPARTMENT_NAME DEPARTMENT_ID 1900 50 1800 20 1700 10 LOCATION_ID DEPARTMENT_ID

Arithmetic Operations ,[object Object],[object Object],[object Object],SELECT LAST_NAME, SALARY, SALARY + 300 FROM EMPLOYEES 17000 17000 24000 SALARY 17300 De Haan 17300 Kochhar 24300 King SALARY + 300 LAST_NAME

The null Value ,[object Object],[object Object],[object Object],SELECT LAST_NAME, MANAGER_ID FROM EMPLOYEES NULL is displayed as empty space or as (null) 100 100 (null) MANAGER_ID De Haan Kochhar King LAST_NAME

Column Alias ,[object Object],[object Object],[object Object],[object Object],[object Object],SELECT LAST_NAME "Name" , 12*SALARY AS "Annual Salary" FROM EMPLOYEES 204000 288000 Annual Salary Kochhar King Name

Concatenation Operator ,[object Object],[object Object],[object Object],SELECT LAST_NAME || JOB_ID AS "Employees" FROM EMPLOYEES De Haan AD_VP Kochhar AD_VP King AD_PRES Employees

Literal Character Strings ,[object Object],[object Object],[object Object],SELECT LAST_NAME || ' is a ' || JOB_ID AS "Employee Details" FROM EMPLOYEES De Haan is a AD_VP Kochhar is a AD_VP King is a AD_PRES Employees

Removing Duplicate Rows ,[object Object],[object Object],SELECT DEPARTMENT_ID FROM EMPLOYEES SELECT DISTINCT DEPARTMENT_ID FROM EMPLOYEES 60 ... 90 90 DEPARTMENT_ID ... 60 90 DEPARTMENT_ID

UNION and INTERSECT ,[object Object],[object Object],[object Object],SELECT FIRST_NAME AS NAME FROM EMPLOYEES UNION SELECT LAST_NAME AS NAME FROM EMPLOYEES Abel Adam Alana Alberto ... NAME

Limiting the Rows Selected ,[object Object],[object Object],SELECT LAST_NAME, DEPARTMENT_ID FROM EMPLOYEES WHERE DEPARTMENT_ID = 90 SELECT FIRST_NAME, LAST_NAME, JOB_ID FROM EMPLOYEES WHERE LAST_NAME = 'Whalen' SELECT LAST_NAME, SALARY FROM EMPLOYEES WHERE SALARY <= 3000 De Haan Kochhar King LAST_NAME 90 90 90 DEPARTMENT_ID

[object Object],[object Object],[object Object],Other Comparison Conditions SELECT LAST_NAME, SALARY FROM EMPLOYEES WHERE SALARY BETWEEN 2500 AND 3000 SELECT FIRST_NAME, LAST_NAME, MANAGER_ID FROM EMPLOYEES WHERE MANAGER_ID IN (100, 101, 201) SELECT FIRST_NAME FROM EMPLOYEES WHERE FIRST_NAME LIKE 'S%'

[object Object],[object Object],[object Object],Other Comparison Conditions (2) SELECT LAST_NAME, MANAGER_ID FROM EMPLOYEES WHERE MANAGER_ID IS NULL SELECT LAST_NAME, JOB_ID, SALARY FROM EMPLOYEES WHERE SALARY >= 1000 AND JOB_ID LIKE '%MAN%' SELECT LAST_NAME FROM EMPLOYEES WHERE COMMISSION_PCT IS NOT NULL OR LAST_NAME LIKE '%S%'

Sorting with ORDER BY ,[object Object],[object Object],[object Object],SELECT LAST_NAME, HIRE_DATE FROM EMPLOYEES ORDER BY HIRE_DATE SELECT LAST_NAME, HIRE_DATE FROM EMPLOYEES ORDER BY HIRE_DATE DESC Kochhar Whalen King LAST_NAME 21-SEP-89 17-SEP-87 17-JUN-87 HIRE_DATE Grant Mourgos Zlotkey LAST_NAME 24-MAY-99 16-NOV-99 29-JAN-00 HIRE_DATE

SQL Language Selecting Data From Multiple Tables

Data from Multiple Tables ,[object Object],Fay Kochhar King LAST_NAME 20 90 90 DEPARTMENT_ID 10 20 90 DEPARTMENT_ID Administration Marketing Executive DEPARTMENT_NAME Kochhar Fay King LAST_NAME Executive Marketing Executive DEPARTMENT_NAME

Cartesian Product ,[object Object],[object Object],SELECT LAST_NAME, DEPARTMENT_NAME FROM EMPLOYEES, DEPARTMENTS Administration King Executive Kochhar Marketing Kochhar .. King King LAST_NAME .. Marketing Executive DEPARTMENT_NAME

Cartesian Product ,[object Object],[object Object],[object Object],[object Object],[object Object]

Types of Joins ,[object Object],[object Object],[object Object],[object Object],[object Object]

Natural Join ,[object Object],SELECT DEPARTMENT_ID, DEPARTMENT_NAME, LOCATION_ID, CITY FROM DEPARTMENTS NATURAL JOIN LOCATIONS ... Executive Administration Shipping IT DEPARTMENT_NAME ... 1700 1700 1500 1400 LOCATION_ID Seattle 10 Seattle 90 ... ... 50 60 DEPARTMENT_ID San Francisco Southlake CITY

Join with USING Clause ,[object Object],SELECT E.EMPLOYEE_ID, E.LAST_NAME, D.LOCATION_ID, D.DEPARTMENT_NAME FROM EMPLOYEES E JOIN DEPARTMENTS D USING (DEPARTMENT_ID) IT 1400 Hunold 103 IT 1400 Ernst 104 ... 1700 LOCATION_ID ... De Haan LAST_NAME ... Executive DEPARTMENT_NAME ... 102 EMPLOYEE_ID

Inner Join with ON Clause ,[object Object],[object Object],SELECT E.EMPLOYEE_ID, E.LAST_NAME, E.DEPARTMENT_ID, D.DEPARTMENT_ID, D.LOCATION_ID FROM EMPLOYEES E JOIN DEPARTMENTS D ON (E.DEPARTMENT_ID = D.DEPARTMENT_ID) 20 20 10 DEPARTMENT_ID 20 20 10 DEPARTMENT_ID Fay Hartstein Whalen LAST_NAME 1800 1800 1700 LOCATION_ID 202 201 200 EMPLOYEE_ID

INNER vs. OUTER Joins ,[object Object],[object Object],[object Object]

INNER JOIN SELECT E.FIRST_NAME || ' ' || E.LAST_NAME AS MANAGER_NAME, D.DEPARTMENT_ID, D.DEPARTMENT_NAME FROM EMPLOYEES E INNER JOIN DEPARTMENTS D ON E.EMPLOYEE_ID=D.MANAGER_ID Shipping 50 Adam Fripp IT 60 Alexander Hunold Public Relations 70 Hermann Baer Human Resources 40 Susan Mavris Purchasing 30 Den Raphaely ... 20 10 DEPARTMENT_ID ... Marketing Administration DEPARTMENT_ NAME ... Michael Hartstein Jennifer Whalen MANAGER_NAME

LEFT OUTER JOIN SELECT E.FIRST_NAME || ' ' || E.LAST_NAME AS MANAGER_NAME, D.DEPARTMENT_ID, D.DEPARTMENT_NAME FROM EMPLOYEES E LEFT OUTER JOIN DEPARTMENTS D ON E.EMPLOYEE_ID=D.MANAGER_ID (null) (null) Jason Mallin (null) (null) Hazel Philtanker (null) (null) Nanette Cambrault (null) (null) Clara Vishney Purchasing 30 Den Raphaely ... 20 10 DEPARTMENT_ID ... Marketing Administration DEPARTMENT_ NAME ... Michael Hartstein Jennifer Whalen MANAGER_NAME

RIGHT OUTER JOIN SELECT E.FIRST_NAME || ' ' || E.LAST_NAME AS MANAGER_NAME, D.DEPARTMENT_ID, D.DEPARTMENT_NAME FROM EMPLOYEES E RIGHT OUTER JOIN DEPARTMENTS D ON E.EMPLOYEE_ID=D.MANAGER_ID Corporate Tax 130 (null) Control And Credit 140 (null) Shareholder Services 150 (null) Treasury 120 (null) Purchasing 30 Den Raphaely ... 20 10 DEPARTMENT_ID ... Marketing Administration DEPARTMENT_ NAME ... Michael Hartstein Jennifer Whalen MANAGER_NAME

FULL OUTER JOIN SELECT E.FIRST_NAME || ' ' || E.LAST_NAME AS MANAGER_NAME, D.DEPARTMENT_ID, D.DEPARTMENT_NAME FROM EMPLOYEES E FULL OUTER JOIN DEPARTMENTS D ON E.EMPLOYEE_ID=D.MANAGER_ID (null) (null) Jason Mallin ... ... ... Shareholder Services 150 (null) (null) (null) Clara Vishney ... ... ... ... 20 10 DEPARTMENT_ID ... Marketing Administration DEPARTMENT_ NAME ... Michael Hartstein Jennifer Whalen MANAGER_NAME

Three-Way Joins ,[object Object],SELECT E.EMPLOYEE_ID, CITY, DEPARTMENT_NAME FROM EMPLOYEES E JOIN DEPARTMENTS D ON D.DEPARTMENT_ID = E.DEPARTMENT_ID JOIN LOCATIONS L ON D.LOCATION_ID = L.LOCATION_ID Administration San Francisco 124 ... Southlake Southlake CITY ... IT IT DEPARTMENT_ NAME ... 104 103 EMPLOYEE_ID

Cross Join ,[object Object],[object Object],[object Object],SELECT LAST_NAME, DEPARTMENT_NAME FROM EMPLOYEES CROSS JOIN DEPARTMENTS Administration King Executive Kochhar .. King King LAST_NAME .. Marketing Executive DEPARTMENT_NAME

Additional Conditions ,[object Object],SELECT E.EMPLOYEE_ID, E.FIRST_NAME || ' ' || E.LAST_NAME AS NAME, E.MANAGER_ID, E.DEPARTMENT_ID, D.DEPARTMENT_NAME FROM EMPLOYEES E JOIN DEPARTMENTS D ON (E.DEPARTMENT_ID = D.DEPARTMENT_ID) WHERE E.MANAGER_ID = 149 Sales 80 149 Ellen Abel 174 Sales 80 149 Alyssa Hutton 175 ... DEPARTMENT_ID ... MANAGER_ID ... NAME ... DEPARTMENT_NAME ... EMPLOYEE_ID

SQL Language Nested SELECT Statements

Nested SELECT Statements ,[object Object],[object Object],SELECT FIRST_NAME, LAST_NAME, SALARY FROM EMPLOYEES WHERE SALARY = (SELECT MAX(SALARY) FROM EMPLOYEES) SELECT FIRST_NAME, LAST_NAME, SALARY FROM EMPLOYEES WHERE DEPARTMENT_ID IN (SELECT DEPARTMENT_ID FROM DEPARTMENTS WHERE DEPARTMENT_NAME='Accounting')

[object Object],[object Object],Using the EXISTS operator SELECT FIRST_NAME, LAST_NAME FROM EMPLOYEES E WHERE EXISTS (SELECT EMPLOYEE_ID FROM JOB_HISTORY JH WHERE DEPARTMENT_ID = 110 AND JH.EMPLOYEE_ID=E.EMPLOYEE_ID)

Group Functions ,[object Object],17000 102 17000 101 6000 104 ... 9000 24000 SALARY ... 103 100 EMPLOYEE_ID 24000 MAX(SALARY)

Group Functions in SQL ,[object Object],[object Object],[object Object],[object Object],[object Object]

AVG() and SUM() Functions ,[object Object],SELECT AVG(SALARY), MAX(SALARY), MIN(SALARY), SUM(SALARY) FROM EMPLOYEES WHERE JOB_ID LIKE '%REP%' 273000 SUM(SALARY) 6000 MIN(SALARY) 11500 MAX(SALARY) 8272.72 AVG(SALARY)

MIN() and MAX() Functions ,[object Object],[object Object],SELECT MIN(HIRE_DATE), MAX(HIRE_DATE) FROM EMPLOYEES SELECT MIN(LAST_NAME), MAX(LAST_NAME) FROM EMPLOYEES 29-JAN-00 MAX(HIRE_DATE) 17-JUN-1987 MIN(HIRE_DATE)

The COUNT( … ) Function ,[object Object],[object Object],SELECT COUNT(*) FROM EMPLOYEES WHERE DEPARTMENT_ID = 50 SELECT COUNT(COMMISSION_PCT) FROM EMPLOYEES WHERE DEPARTMENT_ID = 80 5 COUNT(*) 3 COUNT(COMMISION_PCT)

Group Functions and Nulls ,[object Object],[object Object],SELECT AVG(COMMISSION_PCT) FROM EMPLOYEES .2229 AVG(COMMISSION_PCT)

SQL Language Group Functions and the GROUP BY Statement

Creating Groups of Data EMPLOYEES 11300 23400 16500 20300 6000 20 6500 40 2600 50 4400 2 0 13000 20 10000 40 12000 110 8300 110 2600 50 3000 50 ... 3100 SALARY ... 50 DEPARTMENT_ID ... ... 20 3 00 110 1 6500 40 23400 2 0 11300 50 SUM(SALARY) DEPARTMENT_ID

The GROUP BY Statement ,[object Object],[object Object],[object Object],SELECT < columns> , < group_function(column)> FROM < table> [WHERE < condition> ] [GROUP BY < group_by_expression> ] [ORDER BY < columns >

The GROUP BY Statement ,[object Object],[object Object],SELECT DEPARTMENT_ID, SUM(SALARY) FROM EMPLOYEES GROUP BY DEPARTMENT_ID ... ... 7000 (null) 24900 30 51600 100 SUM(SALARY) DEPARTMENT_ID

Grouping by Several Columns 4400 25000 7500 43500 EMPLOYEES EMPLOYEES ... PU_MAN PU_MAN PU_MAN PU_MAN PU_CLERK PU_CLERK PU_CLERK MK_MAN MK_MAN AD_ASST JOB_ID 11000 30 11500 30 2500 30 2500 30 2500 30 10000 30 11000 30 12000 20 13000 20 ... 4400 SALARY ... 20 DEPARTMENT_ID ... PU_MAN PU_CLERK MK_MAN AD_ASST JOB_ID ... ... 43500 30 7500 30 25000 20 4400 20 SUM(SALARY) DPT_ID

Grouping by Several Columns – Example ,[object Object],SELECT DEPARTMENT_ID, JOB_ID, COUNT(EMPLOYEE_ID), SUM(SALARY) FROM EMPLOYEES GROUP BY DEPARTMENT_ID, JOB_ID ORDER BY SUM(SALARY) DESC ... 80 50 80 DEPARTMENT_ID ... SA_MAN SH_CLERK SA_REP JOB_ID ... ... 61000 5 64300 20 243500 29 SUM(SALARY) COUNT( EMPLOYEE_ID)

Illegal Queries ,[object Object],[object Object],[object Object],[object Object],SELECT DEPARTMENT_ID, COUNT(LAST_NAME) FROM EMPLOYEES SELECT DEPARTMENT_ID, AVG(SALARY) FROM EMPLOYEES WHERE AVG(SALARY) > 8000 GROUP BY DEPARTMENT_ID;

Using GROUP BY with HAVING Clause ,[object Object],SELECT DEPARTMENT_ID, COUNT(EMPLOYEE_ID), AVG (SALARY) FROM EMPLOYEES GROUP BY DEPARTMENT_ID HAVING COUNT(EMPLOYEE_ID) BETWEEN 3 AND 6 60 90 30 100 DEPARTMENT_ID 5760 5 19333.33 3 4150 6 8600 6 AVG (SALARY) COUNT(EMPLOYEE_ID)

Using Grouping Functions and Table Joins ,[object Object],SELECT COUNT(*) AS EMPS, DEPARTMENT_NAME FROM EMPLOYEES E JOIN DEPARTMENTS D ON E.DEPARTMENT_ID=D.DEPARTMENT_ID WHERE HIRE_DATE BETWEEN '1991-1-1' AND '1997-12-31' GROUP BY DEPARTMENT_NAME HAVING COUNT(*) > 5 ORDER BY EMPS DESC 15 19 EMPS Sales Shipping DEPARTMENT_NAME

Oracle Data Types ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Oracle Data Types (2) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

SQL Language Data Definition Language (DDL)

Data Definition Language ,[object Object],[object Object],[object Object],[object Object],[object Object]

Creating Objects ,[object Object],[object Object],[object Object],[object Object],CREATE TABLE PERSONS ( PERSON_ID INTEGER NOT NULL, NAME NVARCHAR2(50) NOT NULL, CONSTRAINT PERSON_PK PRIMARY KEY(PERSON_ID) ) CREATE OR REPLACE VIEW PERSONS_TOP_10 AS SELECT NAME FROM PERSONS WHERE ROWNUM <= 10

Modifying Objects ,[object Object],[object Object],[object Object],-- Add a foreign key constraint TOWN --> COUNTIRY ALTER TABLE TOWN ADD CONSTRAINT TOWN_COUNTRY_FK FOREIGN KEY (COUNTRY_ID) REFERENCES COUNTRY(ID) ENABLE -- Add column COMMENT to the table PERSON ALTER TABLE PERSONS ADD ("COMMENT" VARCHAR2(800)) -- Remove column COMMENT from the table PERSON ALTER TABLE PERSONS DROP COLUMN "COMMENT"

Deleting Objects ,[object Object],[object Object],[object Object],[object Object],[object Object],DROP SEQUENCE SEQ_PERSON DROP CONSTRAINT TRG_PERSON_INSERT DROP TABLE PERSONS

Creating Tables Best Practices

Creating Tables in Oracle ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Creating Tables in Oracle – Example ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

SQL Language Inserting Data in the Tables

Inserting Data ,[object Object],[object Object],[object Object],[object Object],INSERT INTO COUNTRY VALUES ('1', 'Bulgaria', 'Sofia') INSERT INTO COUNTRY(NAME, CAPITAL) VALUES ('Bulgaria', 'Sofia') INSERT INTO COUNTRY(COUNTRY_ID, NAME, CAPITAL) SELECT NULL, COUNTRY, CAPITAL FROM CAPITALS

SQL Language Updating Data in the Tables

Updating Data ,[object Object],[object Object],[object Object],UPDATE PERSONS SET NAME = 'Updated Name' WHERE PERSON_ID = 1 UPDATE EMPLOYEES SET SALARY = SALARY * 1.10 WHERE DEPARTMENT_ID = 3

Updating Joined Tables ,[object Object],UPDATE (SELECT SALARY FROM EMPLOYEES E INNER JOIN DEPARTMENTS D ON E.DEPARTMENT_ID = D.DEPARTMENT_ID WHERE D.NAME = 'Accounting') SET SALARY = SALARY * 1.10

SQL Language Deleting Data from the Tables

Deleting Data ,[object Object],[object Object],[object Object],[object Object],[object Object],DELETE FROM PERSONS WHERE PERSON_ID = 1 DELETE FROM PERSONS WHERE NAME LIKE 'S%' TRUNCATE TABLE PERSONS

Problems ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Problems (2) ,[object Object],[object Object],[object Object],[object Object]

Problems (3) ,[object Object],[object Object],[object Object],[object Object],[object Object]

Problems (6) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Problems (8) ,[object Object],[object Object]

Problems (9) ,[object Object],[object Object],[object Object]

Problems (10) ,[object Object],[object Object],[object Object]

Homework ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Homework (2) ,[object Object],[object Object],[object Object],[object Object],[object Object]

Introduction to-sql

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Introduction to-sql