Chapter 4-1

CSE 4701

Chapter 4 6e & 8 5e: Basic SQL

Prof. Steven A. Demurjian, Sr. Computer Science & Engineering Department

The University of Connecticut191 Auditorium Road, Box U-155

Storrs, CT 06269-3155steve@engr.uconn.edu

http://www.engr.uconn.edu/~steve(860) 486 - 4818

About one third of these slides are being used with the permission of Dr. Ling Lui, Associate Professor, College of Computing, Georgia Tech.

About one-half of these slides have been adapted from the AWL web site for the textbook.

Chapter 4-2

CSE 4701

Relational Languages

A Relational Language Defines Operations to Manipulate Relations Used to Specify Retrieval Requests (Queries) Query Result is Expressed in the Form of a Relation

Classification Relational Algebra (We’ve Discussed) Relational Calculus

To be Briefly Explored as the Basis of ... Structured Query Language (SQL)

Chapter 4-3

CSE 4701

Based on First-Order Predicate Logic Symbol Alphabet

Logic Symbols (e.g., ¬a Set of Constantsa Set of Variablesa Set of n-ary Predicatesa Set of n-ary FunctionsParentheses

Expressions (called well-formed formulae (wff)) Built from this Symbol Alphabet

Classification: Tuple Relational Calculus Domain Relational Calculus

Relational Calculus

Chapter 4-4

CSE 4701

Tuple Relational Calculus

The Primitive Variable is a Tuple Variable Which Specifies a Tuple of a Relation Ranges Over the Tuples of a Relation

In Tuple Relational Calculus, Queries are Specified as {t | F(t)}where t is a Tuple Variable and F is a Formula Consisting of the Atoms and Operators

Chapter 4-5

CSE 4701

EMP(ENO, ENAME, AGE)

PROJ(PNO, PNAME, LOC, MGR)

WORKS(ENO, PNO, DUR) Find the Names of Employees under age 30 { t[ENAME] | tEMP t[AGE]<30}

Find the Names of Employees working on the CAD/CAM Project

{ t[ENAME] | tEMP u(u WORKS t[ENO]uv(vPROJu[PNO]=v[PNO] v[PNAME]=‘CAD/CAM’))

Example

ENAME

(AGE < 30

(EMP))

ENAME

(PNAME=‘CAD/CAM”

(PROJ) PNO (WORKS ENOEMP))

Chapter 4-6

CSE 4701

A formula F is Composed of Atoms Boolean operators ¬ Existential Qualifier Universal Qualifier

Formation rules: Each Atom is a Formula If F and G are Formulae, so are FG, FG, ¬F, and

¬G If F is a Formula, so is (F) If F is a Formula and t is a Free variable in F, then t(F) and t(F) are also Formulae

Nothing else is a Formula

Tuple Relational Calculus

Chapter 4-7

CSE 4701

The Atoms are the Following :• Tuple variables R.t or R(t)• Conditions

s[A] t where s and t are Tuple Variables and A and B are

Components of s and t, Respectively, and

<><=>=specifies that Component A of s stands in relation to component B of t (e.g., s[SALARY] > t[SALARY])

s[A] c where s, A and are as Defined above and c is a Constant

e.g., s[NAME] = 'Smith'.

Tuple Relational Calculus

Chapter 4-8

CSE 4701

Find the names of Employees who have Worked for a Project for more than Two Years { t[ENAME] | tEMP u(u WORKS t[ENO]u

u[DUR]=‘24’))

Find all Managers who are less than 40 years old? { t[MGR] | tPROG u(u WORKS t[PNO]uPN

v(vEMPu[ENO]=v[ENO] v[AGE]<40))

Example

MGR

(AGE<40

EMP ENO (WORKS PNOPROJ))

ENAME

(DUR=24

(WORKS) ENO EMP)

Chapter 4-9

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SQL is a Partial Example of a Tuple Relational Language Simple Queries are all Declarative More Complex Queries are both Declarative and

Procedural (e.g., joins, nested queries) Find the names of employees working on the CAD/CAM

projectSELECT EMP.ENAMEFROM EMP, WORKS, PROJWHERE (EMP.ENO= WORKS.ENO) AND (WORKS.PNO = PROJ.PNO) AND (PROJ.PNAME = “CAD/CAM”)

Tuple Variables are Implicit

SQL: Tuple Relational Calculus-Based

Chapter 4-10

CSE 4701

PNAME, PNAME1

(PROJ LOC = LOC1 PROJ1)

Let Proj1(PNAME1, LOC1) = PNAME, LOC

(PROJ)

Explicit Tuple Variables

Find the Pairs of all Project Names for those Projects that are Located at the same Place

SELECT (P1.PNAME, P2.PNAME)

FROM PROJ P1, PROJ P2

WHERE P1.LOC = P2.LOC

Chapter 4-11

CSE 4701

SQL Components Data Definition Language (DDL)

For External and Conceptual Schemas Views - DDL for External Schemas

Data Manipulation Language (DML) Interactive DML Against External and Conceptual

Schemas Embedded DML in Host PLs (EQL, JDBC, etc.)

Others Integrity (Allowable Values/Referential) Catalog and Dictionary Facilities Transaction Control (Long-Duration and Batch) Authorization (Who can Do What When)

Chapter 4-12

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SQL DDL and DML

Data Definition Language (DDL) Defining the Relational Schema - Relations,

Attributes, Domains - The Meta-DataCREATE TABLE Student: Name(CHAR(30)), SSN(CHAR(9)), GPA(FLOAT(2))CREATE TABLE Courses: Course#(CHAR(6)), Title(CHAR(20)),

Descrip(CHAR(100)), PCourse#(CHAR(6)) Data Manipulation Language (DML)

Defining the Queries Against the SchemaSELECT Name, SSNFrom Student Where GPA > 3.00

Chapter 4-13

CSE 4701

History of SQL

SQL is based on the Relational Tuple Calculus Evolved from SEQUEL: Structured English QUEry

Language - part of IBM’s SYSTEM R, 1974 SQL2 Supported by

ORACLE, SYBASE, INFORMIX, IBM DB2, SQL SERVER, … MS Access, MySQL, …

SQL2 also called SQL/92 is evolved from SQL/86, SQL/89, all were ANSI & ISO standard

Ongoing work on SQL3 with OO Extensions

Chapter 4-14

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Data Definition Language - DDL

A Pre-Defined set of Primitive Types Numeric Character-string Bit-string Additional Types

Defining Domains Defining Schema Defining Tables Defining Views Note: Each DBMS May have their Own DBMS

Specific Data Types - Is this Good or Bad?

Chapter 4-15

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DDL - Primitive Types

Numeric INTEGER (or INT), SMALLINT REAL, DOUBLE PRECISION FLOAT(N) Floating Point with at Least N Digits DECIMAL(P,D) (DEC(P,D) or NUMERIC(P,D))

have P Total Digits with D to Right of Decimal Note that INTs and REALs are Machine Dependent

(Based on Hardware/OS Platform)

Chapter 4-16

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DDL - Primitive Types

Character-String CHAR(N) or CHARACTER(N) - Fixed VARCHAR(N), CHAR VARYING(N), or

CHARACTER VARYING(N) Variable with at Most N Characters

Bit-Strings BIT(N) Fixed VARBIT(N) or BIT VARYING(N)

Variable with at Most N Bits

Chapter 4-17

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DDL - Primitive Types

These Specialized Primitive Types are Used to: Simplify Modeling Process Include “Popular” Types Reduce Composite Attributes/Programming

DATE : YYYY-MM-DD TIME: HH-MM-SS TIME(I): HH-MM-SS-F....F - I Fraction Seconds TIME WITH TIME ZONE: HH-MM-SS-HH-MM TIME-STAMP:

YYYY-MM-DD-HH-MM-SS-F...F{-HH-MM} NOTE: Different DBMS have Different Date/Time

Chapter 4-18

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DDL - What are Domains?

Domains are Similar in Concepts to Programming Language Type Definitions

A Domain can be Defined as Follows:CREATE DOMAIN CITY CHAR(15) DEFAULT ‘<Storrs>’;

CREATE DOMAIN SSNFORMAT CHAR(9); Advantage of Using Domains

Changing a Domain Definition in One Place Changes it Consistently Everywhere it is Used

Default Values Can Be Defined for Domains Constraints Can Be Defined for Domains

Chapter 4-19

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DDL - Dropping a Domain

A Domain is Dropped As Follows:

DROP DOMAIN CITY RESTRICT;

DROP DOMAIN SSNFORMAT CASCADE; Restrict:

Drop Operation Fails If the Domain is Used in Column Definitions

Cascade: Drop Operation Causes Columns to be Defined

Directly on the Underlying Data Type

Chapter 4-20

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What is a SQL Schema?

A Schema in SQL is the Major Meta-Data Construct Create a DB to Contain Multiple Tables

Supports the Definition of: Relation - Table with Name Attributes - Columns and their Types Identification - Primary Key Constraints - Referential Integrity (FK)

Two Part Definition CREATE Schema - Named Database or

Conceptually Related Tables CREATE Table - Individual Tables of the Schema

Chapter 4-21

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DDL-Create/Drop a Schema

Creating a Schema:CREATE SCHEMA MY_COMPANY AUTHORIZATION Demurjian; Schema MY_COMPANY bas Been Created and is

Owner by the User “Demurjian” Tables can now be Created and Added to Schema

Dropping a Schema:DROP SCHEMA MY_COMPANY RESTRICT;DROP SCHEMA MY_COMPANY CASCADE; Restrict:

Drop Operation Fails If Schema is Not Empty Cascade:

Drop Operation Removes Everything in the Schema

Chapter 4-22

CSE 4701

DDL - Create TablesCREATE TABLE EMPLOYEE

( FNAME VARCHAR(15) NOT NULL ,MINIT CHAR ,LNAME VARCHAR(15) NOT NULL ,SSN CHAR(9) NOT NULL ,BDATE DATEADDRESS VARCHAR(30) ,SEX CHAR ,SALARY DECIMAL(10,2) ,SUPERSSN CHAR(9) ,DNO INT NOT NULL ,PRIMARY KEY (SSN) ,FOREIGN KEY (SUPERSSN)

REFERENCES EMPLOYEE(SSN) ,FOREIGN KEY (DNO)

REFERENCES DEPARTMENT(DNUMBER) ) ;

Chapter 4-23

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DDL - Create Tables (continued)

CREATE TABLE DEPARTMENT ( DNAME VARCHAR(15) NOT NULL ,

DNUMBER INT NOT NULL ,MGRSSN CHAR(9) NOT NULL , MGRSTARTDATE DATE , PRIMARY KEY (DNUMBER) , UNIQUE (DNAME) ,FOREIGN KEY (MGRSSN) REFERENCES EMPLOYEE(SSN) ) ;

CREATE TABLE DEPT_LOCATIONS (DNUMBER INT NOT NULL ,

DLOCATION VARCHAR(15) NOT NULL , PRIMARY KEY (DNUMBER, DLOCATION) ,

FOREIGN KEY (DNUMBER) REFERENCES DEPARTMENT(DNUMBER) ) ;

Chapter 4-24

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DDL - Create Tables (continued)

CREATE TABLE PROJECT (PNAME VARCHAR(15) NOT NULL ,

PNUMBER INT NOT NULL ,PLOCATION VARCHAR(15) , DNUM INT NOT NULL , PRIMARY KEY (PNUMBER) , UNIQUE (PNAME) ,

FOREIGN KEY (DNUM) REFERENCES DEPARTMENT(DNUMBER) ) ;

CREATE TABLE WORKS_ON (ESSN CHAR(9) NOT NULL , PNO INT NOT NULL ,

HOURS DECIMAL(3,1) NOT NULL , PRIMARY KEY (ESSN, PNO) , FOREIGN KEY (ESSN)

REFERENCES EMPLOYEE(SSN) ,FOREIGN KEY (PNO)

REFERENCES PROJECT(PNUMBER) ) ;

Chapter 4-25

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DDL - Create Tables with Constraints

CREATE TABLE EMPLOYEE( . . . ,DNO INT NOT NULL DEFAULT 1,CONSTRAINT EMPPK

PRIMARY KEY (SSN) ,CONSTRAINT EMPSUPERFK

FOREIGN KEY (SUPERSSN) REFERENCES EMPLOYEE(SSN)ON DELETE SET NULLON UPDATE CASCADE ,

CONSTRAINT EMPDEPTFKFOREIGN KEY (DNO) REFERENCES DEPARTMENT(DNUMBER) ON DELETE SET DEFAULT ON UPDATE CASCADE );

Chapter 4-26

CSE 4701

DDL - Create Tables with Constraints

CREATE TABLE DEPARTMENT( . . . ,MGRSSN CHAR(9) NOT NULL

DEFAULT '888665555' ,. . . ,CONSTRAINT DEPTPK

PRIMARY KEY (DNUMBER) ,CONSTRAINT DEPTSK

UNIQUE (DNAME),CONSTRAINT DEPTMGRFK

FOREIGN KEY (MGRSSN) REFERENCES EMPLOYEE(SSN)ON DELETE SET DEFAULTON UPDATE CASCADE );

Chapter 4-27

CSE 4701

CREATE TABLE Supplier_Parts ( S# CHAR(5) NOT NULL, P# CHAR(6) NOT NULL, QTY INTEGER, PRIMARY KEY (S# P#) FOREIGN KEY S# REFERENCE SUPPLIER

ON DELETE CASCADE, REFERENCE PART

ON DELETE RESTRICT);

Create and Drop: Summary Defines Types and Order of Attributes in a Relation May Specify Which Attribute Are Keys and Which

Cannot Be Null Create a New Empty Table May Define DELETION Effect by Cascade/Restricted

Chapter 4-28

CSE 4701

SQL Data Definition

Drop Table A Relation Can Be Dropped at Any Time Drop Will Delete Both Definition and Data All Views, Indexes, and FKs are Dropped

DROP TABLE SUPPLIER; Alter Table

Add New Attributes or PK and FK to the Table All Existing Records are Expanded With Nulls, but

Not Physically Changed.ALTER TABLE SUPPLIERADD DISCOUNT SMALLINT;

Chapter 4-29

CSE 4701

DDL - Drop Tables

Command:

DROP TABLE EMPLOYEE RESTRICT;

DROP TABLE DEPARTMENT CASCADE; Restrict:

Drop Operation fails if the Table is Referenced by View and/or Constraint Definitions

Cascade: Drop Operation Removes Referencing View and

Constraint Definitions

Chapter 4-30

CSE 4701

DDL - Change Table Structure

Add a Column to a Table:

ALTER TABLE EMPLOYEE

ADD JOB VARCHAR(12); No DEFAULT Implies NULL Values for all Tuples

Drop a Column from a tableALTER TABLE EMPLOYEE DROP JOB RESTRICT (or CASCADE);

Restrict: Drop Operation Fails if Column is Referenced

Cascade: Drop Operation Removes Referencing View and Constraint Definitions

Chapter 4-31

CSE 4701

Chinook sql file

Chapter 4-32

CSE 4701

Chinook sql file

Chapter 4-33

CSE 4701

Chinook sql file

Chapter 4-34

CSE 4701

Chinook sql file

Chapter 4-35

CSE 4701

Chinook sql file

Chapter 4-36

CSE 4701

Data Manipulation Language - DML

SQL has the SELECT Statement for Retrieving Info. from a Database (Not Relational Algebra Select)

SQL vs. Formal Relational Model SQL Allows a Table (Relation) to have Two or More

Identical Tuples in All Their Attribute Values Hence, an SQL Table is a Multi-set (Sometimes

Called a Bag) of Tuples; it is Not a Set of Tuples SQL Relations Can Be Constrained to Sets by

PRIMARY KEY or UNIQUE Attributes Using the DISTINCT Option in a Query

Chapter 4-37

CSE 4701

Interactive DML - Main Components

Select-from-where Statement Contains: Select Clause - Chosen Attributes/Columns From Clause - Involved Tables Where Clause - Constrain Tuple Values Tuple Variables - Distinguish Among Same Names

in Different Tables String Matching - Detailed Matching Including

ExactStarts WithNear

Ordering of Rows - Sorting Tuple Results

Chapter 4-38

CSE 4701

Interactive DML - Main Components

Select-from-where Statement Contains: Set Operations - Search to See if a Value is in Set Built-in Functions - Count, Mix, Max, Sum, Avg Nested Subqueries - Queries within Queries Joins - As Discussed for Relational Algebra Recursive Queries (Defer - Part of SQL3) Modification-Based Selects for

Insert - Create a New TupleDelete - Remove Existing Tuple(s)Update - Change Existing Tuple(s)

Chapter 4-39

CSE 4701 SELECT target-list

FROM relation-listWHERE condition or subqueryGROUP BY attribute-listHAVING conditionORDER BY attribute-list

Skeleton Query:

SELECT - relational “project” WHERE - relational “select” and/or “join”

In principle, a SQL query equals to an algebra expression

target-listconditionrelation-list

SQL Data Manipulation

Chapter 4-40

CSE 4701

Format:

Equivalent Algebra Statement:

SELECT Specifies the Columns of the Query Result FROM Specifies the Tables to Be Used in the Query WHERE Specifies the Query Condition

Restriction: Must Refer to Columns of the Tables in the FROM Clause

SELECT A1, A2, ... An

FROM R1 , R2 , ... Rm

WHERE Predicate (Boolean/Set Expression)

p A1 , A2 , ... An ( s P(R1 R 2 R m)) ...

Simple Select-From-Where

Chapter 4-41

CSE 4701

Recall Prior Schema

Chapter 4-42

CSE 4701

…and Corresponding DB Tables

Which Represent Tuples/Instances of Each Relation

1455

ASCnullWBnullnull

Chapter 4-43

CSE 4701

…and Corresponding DB Tables

Chapter 4-44

CSE 4701

Simple SQL Queries

Query 0: Retrieve the Birthdate and Address of the Employee whose Name is 'John B. Smith'.SELECT BDATE, ADDRESSFROM EMPLOYEEWHERE FNAME='John' AND MINIT='B’ AND LNAME='Smith’

Which Row(s) are Selected?

Note: While All of these Next Queries are from Chapter 4, Some are From “Earlier” Edition

BSCnullWB nullnull

Chapter 4-45

CSE 4701

Simple SQL Queries

Query 1: Retrieve Name and Address of all Employees who work for the 'Research' DepartmentSELECT FNAME, MINIT, LNAME, ADDRESS, DNAMEFROM EMPLOYEE, DEPARTMENTWHERE DNAME='Research' AND DNUMBER=DNO

What Action is Being Performed?

Chapter 4-46

CSE 4701

Simple SQL Queries - Result

Theta Join on DNO=DNUMBER

Chapter 4-47

CSE 4701

Simple SQL Queries – Fully Qualified

The Full Table Name with “.” Notation Differentiates Among the Attributes

Query 1: Retrieve Name and Address of all Employees who work for the 'Research' DepartmentSELECT EMPLOYEE.FNAME, EMPLOYEE.MINIT,

EMPLOYEE. LNAME,EMPLOYEE.ADDRESS, DEPARTMENT.DNAMEFROM EMPLOYEE, DEPARTMENTWHERE DEPARTMENT.DNAME='Research' AND

DEPARTMENT.DNUMBER= EMPLOYEE.DNO

Chapter 4-48

CSE 4701

Simple SQL Queries

Query 2: For Every Project in 'Stafford', list the Project Number, the Controlling Dept. Number, and the Dept. Manager's Last Name, Address, and BirthdateSELECT PNUMBER, DNUM, LNAME, BDATE,ADDRESSFROM PROJECT, DEPARTMENT, EMPLOYEEWHERE DNUM=DNUMBER AND MGRSSN=SSN AND

PLOCATION='Stafford' In Q2, there are Two Join Conditions:

The Join Condition DNUM=DNUMBER Relates a Project to its Controlling Department

The Join Condition MGRSSN=SSN Relates the Controlling Department to the Employee who Manages that Department

Chapter 4-49

CSE 4701

Query Results

ASCnullWBnullnull

SELECT PNUMBER, DNUM, LNAME, BDATE,ADDRESSFROM PROJECT, DEPARTMENT, EMPLOYEEWHERE DNUM=DNUMBER AND MGRSSN=SSN AND

PLOCATION='Stafford'

Chapter 4-50

CSE 4701

Qualification of Attributes

In SQL, the Same Name for Two (or More) Attributes is Allowed if Attributes are in Different Relations

In Those Cases, Query Must Qualify by Prefixing the Relation Name to the Attribute Name EMPLOYEE.LNAME, DEPARTMENT.DNAME

Aliases: When Queries Must Refer to the Same Relation Twice Alias is Akin to a Variable in a PL - Reference In These Situations, it is Considered that there are

Two Different Copies of the Same Relation Let’s See Examples of Both Concepts

Chapter 4-51

CSE 4701

Attribute Qualification

Query 8: For Each Employee, Retrieve the Employee's Name, and Name of his or her Immediate SupervisorSELECT E.FNAME, E.LNAME, S.FNAME, S.LNAME FROM EMPLOYEE E SWHERE E.SUPERSSN=S.SSN

E and S are aliases for the EMPLOYEE relation E Represents Employees in the Role of Supervisees S Represents Employees in the Role of Supervisor

Another Form of Query 8 is:SELECT E.FNAME, E.LNAME, S.FNAME, S.LNAMEFROM EMPLOYEE AS E, EMPLOYEE AS SWHERE E.SUPERSSN=S.SSN

Chapter 4-52

CSE 4701

Query Results

ASCnullWBnullnull

SELECT E.FNAME, E.LNAME, S.FNAME, S.LNAMEFROM EMPLOYEE AS E, EMPLOYEE AS SWHERE E.SUPERSSN=S.SSN

Chapter 4-53

CSE 4701

Unspecified WHERE Clause

A Missing Where-clause Indicates No Condition; All Tuples of Relations in From-clause Are Selected

Query 9: Retrieve the SSN Values for All EmployeesSELECT SSNFROM EMPLOYEE

More Than One Relation and No Join Condition Results in the CARTESIAN PRODUCT of Tuples

Query 10: SELECT SSN, DNAMEFROM EMPLOYEE, DEPARTMENT

Overlooking Selection and Join Conditions in the Where-Clause Likely Yields Incorrect and Very Large Relations May Result

Chapter 4-54

CSE 4701

Use of * and Distinct

When a * is Used, All of the Attributes are ChosenQ1C:SELECT *FROM EMPLOYEEWHERE DNO=5

Q1D:SELECT *FROM EMPLOYEE, DEPARTMENTWHERE DNAME='Research' AND DNO=DNUMBER

SQL Does Not Support Sets so Duplicates are RetrievedQ11: SELECT SALARY FROM EMPLOYEE

Distinct Removes Duplicates Q11A: SELECT DISTINCT SALARY FROM EMPLOYEE

Chapter 4-55

CSE 4701

SELECT * in MySQL WorkBench

Chapter 4-56

CSE 4701

SELECT * in MySQL WorkBench

Chapter 4-57

CSE 4701

Set Operations - Union/Intersection/Minus

Not all DBMS Support Intersection/Minus Union: The two Relations must have Same Attributes

and the Attributes must Appear in the Same Order Query 4: All Project Numbers for Projects with

Employee 'Smith' as a Worker or as a Manager (SELECT PNAMEFROM PROJECT, DEPARTMENT, EMPLOYEEWHERE DNUM=DNUMBER AND MGRSSN=SSN AND LNAME='Smith')UNION(SELECT PNAMEFROM PROJECT, WORKS_ON, EMPLOYEEWHERE PNUMBER=PNO AND ESSN=SSN AND

LNAME='Smith')

Chapter 4-58

CSE 4701

Set Operations - Union/Intersection/Minus

Utilizing the DISTINCT KEYWORD Query 4: Make a list of all project numbers for projects

that involve an employee whose last name is ‘Smith’, either as a worker or as a manager of the department that controls the project.(SELECT DISTINCT PNAMEFROM PROJECT, DEPARTMENT, EMPLOYEEWHERE DNUM=DNUMBER AND MGRSSN=SSN AND LNAME='Smith')UNION(SELECT DISTINCT PNAMEFROM PROJECT, WORKS_ON, EMPLOYEEWHERE PNUMBER=PNO AND ESSN=SSN AND

LNAME='Smith')

Chapter 4-59

CSE 4701

Substring Comparison in SQL Queries

In Regard to Strings, Most DBMSs Support SQL Queries for Exact, Near, and Starts with Matching

LIKE is Used to Compare Partial Strings '%' (or '*') Replaces an Arbitrary # of characters

'_' replaces a single arbitrary character Query 12: Retrieve all Employees whose Address is in

Houston, Texas. SELECT FNAME, LNAMEFROM EMPLOYEEWHERE ADDRESS LIKE '%Houston,TX% '

Houston, TX can be anywhere within the ADDRESS VAR CHAR String

Chapter 4-60

CSE 4701

Substring Comparison in SQL Queries

The LIKE Operator Allows us to get Around the Fact that each Value is Considered Atomic and Indivisible

SQL: Character String Attribute values are not Atomic Query 12A: Retrieve all employees who were born

during the 1950s. SELECT FNAME, LNAMEFROM EMPLOYEEWHERE BDATE LIKE ' __5_______'

There are two “_” before 5 and seven “_” after 5

Chapter 4-61

CSE 4701

Arithmetic Operations in SQL Queries

Standard Arithmetic Operators '+', '-'. '*', and '/' can be Applied to Numeric Values in an SQL Query Result

Query 13: Show the Effect of Giving all Employees who work on the 'ProductX' project a 10% raise.SELECT FNAME, LNAME, 1.1*SALARYFROM EMPLOYEE, WORKS_ON, PROJECTWHERE SSN=ESSN AND PNO=PNUMBER

AND PNAME='ProductX'

Chapter 4-62

CSE 4701

ORDER BY Clause in SQL Queries

ORDER BY used to Sort the Tuples in a Query Result based on the Values of one or More Attribute(s)

Query 15: Retrieve a list of Employees and the Projects each works in, ordered by Dept., and within each Dept., alphabetically by Employee last nameSELECT DNAME, LNAME, FNAME, PNAMEFROM DEPARTMENT, EMPLOYEE,

WORKS_ON, PROJECTWHERE DNUMBER=DNO AND SSN=ESSN

AND PNO=PNUMBERORDER BY DNAME, LNAME

Default is Ascending - Can be ASC/DESC as we’ll see in a Later Example in Chapter 5

Chapter 4-63

CSE 4701

Natural Join Queries

Specially Tells SQL that a Natural Join is Defined Between Tables

SELECT * FROM COUNTRIES NATURAL JOIN CITIES SELECT * FROM COUNTRIES JOIN CITIES USING

(COUNTRY, COUNTRY_ISO_CODE) Note that * Expands the JOIN to:

All the common columns Every column in the first (left) table that is not a

common column Every column in the second (right) table that is not a

common column Natural Join in the FROM LIST

Chapter 4-64

CSE 4701

Homework 3 from Spr 2015 Problem 6.18 from the 6th

edition done in SQL and NOT relational expressions

Chapter 4-65

CSE 4701

Problem 6.18 in 6th edition

a. How many copies of the book titled The Lost Tribe are owned by the library branch whose name is ‘Sharpstown’?

SELECT NoOfCopiesFROM ( (BOOK NATURAL JOIN BOOK_COPIES )

NATURAL JOIN LIBRARY_BRANCH )WHERE Title='The Lost Tribe' AND BranchName='Sharpstown’

Ans = No_Of_Copies( (BranchName=‘Sharpstown’ (LIBRARY-BRANCH)) * BaB)

BranchID

BaB= (BOOKCOPIES *(Title=‘The Lost Tribe’

(BOOK))) )

BookId

Chapter 4-66

CSE 4701

Problem 6.18 in 6th edition

b. How many copies of the book titled The Lost Tribe are owned by eachlibrary branch?

SELECT BranchName, NoOfCopiesFROM ( (BOOK NATURAL JOIN BOOK_COPIES )

NATURAL JOIN LIBRARY_BRANCH )WHERE Title='The Lost Tribe'

Ans = BranchName, No_Of_Copies( (Title=‘The Lost Tribe’ (BOOK)) * CaB)

BookId

CaB = BOOKCOPIES * LIBRARY_BRANCH)BranchId

Chapter 4-67

CSE 4701

Homework 3 from Spr 2015

Problem 4.10 in 6th edition

Chapter 4-68

CSE 4701

Problem 4.10 in 6th edition

Chapter 4-69

CSE 4701

Problem 4.10 in 6th edition

(a) Retrieve the names of employees in department 5 who work more than 10 hours per week on the 'ProductX' project.

SELECT LNAME, FNAMEFROM EMPLOYEE, WORKS_ON, PROJECTWHERE DNO=5 AND SSN=ESSN AND PNO=PNUMBER AND PNAME='ProductX' AND HOURS>10

LNAME FNAMESmith JohnEnglish Joyce

(b) List the names of employees who have a dependent with the same first name as themselves.

SELECT LNAME, FNAMEFROM EMPLOYEE, DEPENDENTWHERE SSN=ESSN AND FNAME=DEPENDENT_NAME

Result (empty):

Chapter 4-70

CSE 4701

Problem 4.10 in 6th edition

(c) Find the names of employees that are directly supervised by 'Franklin Wong'.

SELECT E.LNAME, E.FNAMEFROM EMPLOYEE E, EMPLOYEE SWHERE S.FNAME='Franklin' AND

S.LNAME='Wong' AND E.SUPERSSN=S.SSN

LNAME FNAMESmith JohnNarayan RameshEnglish Joyce

(h) Retrieve the average salary of all female employees.

SELECT AVG (SALARY)FROM EMPLOYEEWHERE SEX='F’

Result:AVG(SALARY)31000

Chapter 4-71

CSE 4701

INSERT SQL Queries

Add one or more Tuples to a Relation, with Attribute values Listed in the order specified in the CREATE

Update 1: INSERT INTO EMPLOYEE

VALUES ('Richard','K','Marini', '653298653', '30-DEC-52', '98 Oak Forest,Katy,TX', 'M',

37000,'987654321', 4 ) Another Form of Update 1:

INSERT INTO EMPLOYEE (FNAME, LNAME, SSN)VALUES ('Richard','K','Marini')

All PK and FK Values must be Provided Nulls are Allowed DDL Constraints are Enforced

Chapter 4-72

CSE 4701

INSERT SQL Queries

More Sophisticated Insert can Involve Query Update 3A:

CREATE TABLE DEPTS_INFO(DEPT_NAME VARCHAR(10),

NO_OF_EMPS INTEGER, TOTAL_SAL INTEGER);

Update 3B: INSERT INTO DEPTS_INFO (DEPT_NAME,

NO_OF_EMPS, TOTAL_SAL)

SELECT DNAME, COUNT (*), SUM (SALARY) FROM DEPARTMENT, EMPLOYEEWHERE DNUMBER=DNOGROUP BY DNAME ;

Chapter 4-73

CSE 4701

Program Level INSERTS

Mass Import into DB Consider Chinook_MySql.sql

Chapter 4-74

CSE 4701

Program Level INSERTS

Importing Excel Directly into MySQL Many Available Tools http://excel2mysql.net/

Importing an XML File directly into MySQL LOAD XML LOCAL INFILE '/pathtofile/file.xml'

INTO TABLE my_tablename SET ID=NULL; Tools such as: http://www.navicat.com/

Likewise – Ability to EXPORT as well SQL Data Export and Import Wizard For MySQL See: https://dev.mysql.com/doc/workbench/en/wb-admin-

export-import-management.html

Chapter 4-75

CSE 4701

DELETE SQL Queries

Sample Deletes IncludeDELETE FROM EMPLOYEEWHERE LNAME='Brown'

DELETE FROM EMPLOYEEWHERE SSN='123456789’

DELETE FROM EMPLOYEEWHERE DNO IN

(SELECT DNUMBER FROM DEPARTMENT

WHERE DNAME='Research')

DELETE FROM EMPLOYEE No. of Tuples Deleted Dependent on WHERE Clause Referential Integrity is Enforced During DELETE

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UPDATE SQL Queries

Used to Modify Attribute Values of One or More Selected Tuples

A Where-clause Selects the Tuples to Be Modified An Additional Set-Clause Specifies the Attributes to Be

Modified and Their New Values Each Command Modifies Tuples in the Same Relation Referential Integrity Must Be Enforced

UPDATE PROJECT SET PLOCATION = 'Bellaire', DNUM = 5

WHERE PNUMBER=10

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UPDATE SQL Queries

Give all Employees in the 'Research' Dept. a 10% raise UPDATE EMPLOYEE

SET SALARY = SALARY *1.1WHERE DNO IN

(SELECT DNUMBER FROM DEPARTMENT WHERE DNAME='Research')

Modified SALARY Value Depends on the Original SALARY Value in each Tuple

SALARY = SALARY *1.1 - Use PL Interpretation

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Concluding Remarks What have we Seen in Chapter 4?

Complete Data Definition in SQLCreating SchemaCreating/Dropping TablesFKs and PKsBasic Data Manipulation in SQLDifferent SelectsAggregate FunctionsInsert, Update, and Delete

Strongly Encouraged to Engage in Practice with your DBMS of Choice for your Project