2009.10.06 - SLIDE 1IS 257 – Fall 2009 SQL and Client Applications University of California,...

IS 257 – Fall 2009 2009.10.06 - SLIDE 1

SQL and Client Applications

University of California, Berkeley

School of Information

IS 257: Database Management

IS 257 – Fall 2009 2009.10.06 - SLIDE 2

Lecture Outline

• Review– Relational Operations– Relational Algebra– Relational Calculus– Introduction to SQL

• Introduction to SQL and MySQL

• Application Development in Access

IS 257 – Fall 2009 2009.10.06 - SLIDE 3

Lecture Outline


• Introduction to SQL and MySQL (continued)


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Relational Algebra Operations

• Select

• Project

• Product

• Union

• Intersect

• Difference

• Join

• Divide

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Select

• Extracts specified tuples (rows) from a specified relation (table).

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Project

• Extracts specified attributes(columns) from a specified relation.

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Join

• Builds a relation from two specified relations consisting of all possible concatenated pairs, one from each of the two relations, such that in each pair the two tuples satisfy some condition. (E.g., equal values in a given col.)

A1 B1A2 B1A3 B2

B1 C1B2 C2B3 C3

A1 B1 C1A2 B1 C1A3 B2 C2

(Naturalor Inner)

Join

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Outer Join

• Outer Joins are similar to PRODUCT -- but will leave NULLs for any row in the first table with no corresponding rows in the second.

A1 B1A2 B1A3 B2A4 B7

B1 C1B2 C2B3 C3

A1 B1 C1A2 B1 C1A3 B2 C2A4 * *

Outer Join

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Join ItemsPart # Name Price Count

1 Big blue widget 3.76 22 Small blue Widget 7.35 43 Tiny red widget 5.25 74 large red widget 157.23 235 double widget rack 10.44 126 Small green Widget 30.45 587 Big yellow widget 7.96 18 Tiny orange widget 81.75 429 Big purple widget 55.99 9

Invoice # Part # Quantity93774 3 1084747 23 188367 75 288647 4 3

776879 22 565689 76 1293774 23 1088367 34 2

Invoice # Cust # Rep #93774 3 184747 4 188367 5 288647 9 1

776879 2 265689 6 2

Cust # COMPANY STREET1 STREET2 CITY STATE ZIPCODE

1Integrated Standards Ltd. 35 Broadway Floor 12 New York NY 02111

2 MegaInt Inc. 34 Bureaucracy Plaza Floors 1-172 Phildelphia PA 03756

3 Cyber Associates3 Control Elevation Place

Cyber Assicates Center Cyberoid NY 08645

4General Consolidated 35 Libra Plaza Nashua NH 09242

5Consolidated MultiCorp 1 Broadway Middletown IN 32467

6Internet Behometh Ltd. 88 Oligopoly Place Sagrado TX 78798

7Consolidated Brands, Inc.

3 Independence Parkway Rivendell CA 93456

8 Little Mighty Micro 34 Last One Drive Orinda CA 94563

9 SportLine Ltd. 38 Champion Place Suite 882 Compton CA 95328

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Relational Algebra

• What is the name of the customer who ordered Large Red Widgets?– Select “large Red Widgets” from Part as

temp1– Join temp1 with Line-item on Part # as temp2– Join temp2 with Invoice on Invoice # as temp3– Join temp3 with customer on cust # as temp4– Project Name from temp4

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Relational Calculus

• Relational Algebra provides a set of explicit operations (select, project, join, etc) that can be used to build some desired relation from the database.

• Relational Calculus provides a notation for formulating the definition of that desired relation in terms of the relations in the database without explicitly stating the operations to be performed

• SQL is based on the relational calculus.

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SQL - History

• Structured Query Language

• SEQUEL from IBM San Jose

• ANSI 1992 Standard is the version used by most DBMS today (SQL92)

• Basic language is standardized across relational DBMSs. Each system may have proprietary extensions to standard.

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Lecture Outline


• Introduction to SQL (continued)


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SQL Uses

• Database Definition and Querying– Can be used as an interactive query language– Can be imbedded in programs

• Relational Calculus combines Select, Project and Join operations in a single command: SELECT

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SELECT

• Syntax:– SELECT [DISTINCT] attr1, attr2,…, attr3

FROM rel1 r1, rel2 r2,… rel3 r3 WHERE condition1 {AND | OR} condition2 ORDER BY attr1 [DESC], attr3 [DESC]

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SELECT

• Syntax:– SELECT a.author, b.title FROM authors a,

bibfile b, au_bib c WHERE a.AU_ID = c.AU_ID and c.accno = b.accno ORDER BY a.author ;

• Examples in Access...

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SELECT Conditions

• = equal to a particular value• >= greater than or equal to a particular value• > greater than a particular value• <= less than or equal to a particular value• <> not equal to a particular value• LIKE “*term*” (may be other wild cards in other

systems)• IN (“opt1”, “opt2”,…,”optn”)• BETWEEN val1 AND val2• IS NULL

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Relational Algebra Selection using SELECT

• Syntax:– SELECT * FROM rel1 WHERE condition1

{AND | OR} condition2;

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Relational Algebra Projection using SELECT

• Syntax:– SELECT [DISTINCT] attr1, attr2,…, attr3

FROM rel1 r1, rel2 r2,… rel3 r3;

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Relational Algebra Join using SELECT

• Syntax:– SELECT * FROM rel1 r1, rel2 r2 WHERE

r1.linkattr = r2.linkattr ;

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Sorting

• SELECT BIOLIFE.[Common Name], BIOLIFE.[Length (cm)]

FROM BIOLIFE

ORDER BY BIOLIFE.[Length (cm)] DESC;

Note: the square brackets are not part of the standard,But are used in Access for names with embedded blanks

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Subqueries

• SELECT SITES.[Site Name], SITES.[Destination no]

FROM SITES

WHERE sites.[Destination no] IN (SELECT [Destination no] from DEST where [avg temp (f)] >= 78);

• Can be used as a form of JOIN.

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Aggregate Functions

• Count• Avg• SUM• MAX• MIN• Others may be available in different

systems

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Using Aggregate functions

• SELECT attr1, Sum(attr2) AS name FROM tab1, tab2 ...

GROUP BY attr1, attr3 HAVING condition;

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Using an Aggregate Function

• SELECT DIVECUST.Name, Sum([Price]*[qty]) AS Total

FROM (DIVECUST INNER JOIN DIVEORDS ON DIVECUST.[Customer No] = DIVEORDS.[Customer No]) INNER JOIN DIVEITEM ON DIVEORDS.[Order No] = DIVEITEM.[Order No]

GROUP BY DIVECUST.Name HAVING (((DIVECUST.Name) Like

"*Jazdzewski"));

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GROUP BY

• SELECT DEST.[Destination Name], Count(*) AS Expr1

FROM DEST INNER JOIN DIVEORDS ON DEST.[Destination Name] = DIVEORDS.Destination

GROUP BY DEST.[Destination Name]

HAVING ((Count(*))>1);

• Provides a list of Destinations with the number of orders going to that destination

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Lecture Outline


• Introduction to SQL and MySQL (continued)


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MySQL

• The tag-line at http://www.mysql.com is– The world's most popular open source database

• It is true, it is the most widely used open source database system with users and uses that range from individuals to major corporations and includes…– Evite– Friend Finder Network– Friendster– Google (not for search though )– PriceGrabber.com– Ticketmaster– Yahoo!– The US Census bureau– and many, many others

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MySQL myths

• The MySQL.com web site contains a list of common myths and misconceptions about MySQL and refutes them:– MYTH: MySQL is a new, untested database

management system – MYTH: MySQL doesn’t support transactions like other

proprietary database engines (it is supposed to be in the version we use here)

– MYTH: MySQL is only for small, departmental, or web-based applications

– MYTH: MySQL doesn’t offer enterprise-class features – MYTH: MySQL doesn’t have the type of support large

corporations need – MYTH: MySQL isn’t open source any more

IS 257 – Fall 2009 2009.10.06 - SLIDE 30

MySQL documentation

• MySQL is available for download from MySQL.com

• In addition that site has complete online documentation for the MySQL system and for the mysql client program in their ‘Developer Zone’– The online manuals are quite readable and

have lot of examples to help you

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SQL Commands

• Data Definition Statements– For creation of relations/tables…

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CREATE Table

• CREATE TABLE table-name (col_name1 col_definition1 [PRIMARY KEY], col_name2 col_definition2,…,col_nameN col_definitionN);

• Adds a new table with the specified attributes (and types) to the database.

IS 257 – Fall 2009 2009.10.06 - SLIDE 33

Access Data Types (Not MySQL)

• Numeric (1, 2, 4, 8 bytes, fixed or float)• Text (255 max)• Memo (64000 max)• Date/Time (8 bytes)• Currency (8 bytes, 15 digits + 4 digits decimal)• Autonumber (4 bytes)• Yes/No (1 bit)• OLE (limited only by disk space)• Hyperlinks (up to 64000 chars)

IS 257 – Fall 2009 2009.10.06 - SLIDE 34

Access Numeric types

• Byte – Stores numbers from 0 to 255 (no fractions). 1 byte

• Integer– Stores numbers from –32,768 to 32,767 (no fractions) 2 bytes

• Long Integer (Default) – Stores numbers from –2,147,483,648 to 2,147,483,647 (no fractions).

4 bytes

• Single– Stores numbers from -3.402823E38 to –1.401298E–45 for negative

values and from 1.401298E–45 to 3.402823E38 for positive values.4 bytes

• Double– Stores numbers from –1.79769313486231E308 to –

4.94065645841247E–324 for negative values and from 1.79769313486231E308 to 4.94065645841247E–324 for positive values. 15 8 bytes

• Replication ID– Globally unique identifier (GUID) N/A 16 bytes

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MySQL Data Types

• MySQL supports all of the standard SQL numeric data types. These types include the exact numeric data types (INTEGER, SMALLINT, DECIMAL, and NUMERIC), as well as the approximate numeric data types (FLOAT, REAL, and DOUBLE PRECISION). The keyword INT is a synonym for INTEGER, and the keyword DEC is a synonym for DECIMAL

• Numeric (can also be declared as UNSIGNED)– TINYINT (1 byte)– SMALLINT (2 bytes)– MEDIUMINT (3 bytes)– INT (4 bytes)– BIGINT (8 bytes)– NUMERIC or DECIMAL– FLOAT – DOUBLE (or DOUBLE PRECISION)

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MySQL Data Types

• The date and time types for representing temporal values are DATETIME, DATE, TIMESTAMP, TIME, and YEAR. Each temporal type has a range of legal values, as well as a “zero” value that is used when you specify an illegal value that MySQL cannot represent– DATETIME '0000-00-00 00:00:00'– DATE '0000-00-00'– TIMESTAMP (4.1 and up) '0000-00-00 00:00:00'– TIMESTAMP (before 4.1) 00000000000000– TIME '00:00:00'– YEAR 0000

IS 257 – Fall 2009 2009.10.06 - SLIDE 37

MySQL Data Types

• The string types are CHAR, VARCHAR, BINARY, VARBINARY, BLOB, TEXT, ENUM, and SET

• Maximum length for CHAR and VARCHAR is 255

• For longer things there is BLOB and TEXT

Value CHAR(4) Storage VARCHAR(4) Storage"" " " 4 "" 1"ab" "ab " 4 "ab" 3"abcd" "abcd" 4 "abcd" 5"abcdefg" "abcd" 4 "abcd" 5

IS 257 – Fall 2009 2009.10.06 - SLIDE 38

MySQL Data Types

• A BLOB is a binary large object that can hold a variable amount of data.

• The four BLOB types are TINYBLOB, BLOB, MEDIUMBLOB, and LONGBLOB. These differ only in the maximum length of the values they can hold

• The four TEXT types are TINYTEXT, TEXT, MEDIUMTEXT, and LONGTEXT. These correspond to the four BLOB types and have the same maximum lengths and storage requirements

• TINY=1byte, BLOB and TEXT=2bytes, MEDIUM=3bytes, LONG=4bytes

IS 257 – Fall 2009 2009.10.06 - SLIDE 39

MySQL Data Types

• BINARY and VARBINARY are like CHAR and VARCHAR but are intended for binary data of 255 bytes or less

• ENUM is a list of values that are stored as their addresses in the list– For example, a column specified as ENUM('one', 'two', 'three')

can have any of the values shown here. The index of each value is also shown:

• Value = Index• NULL = NULL• ‘’ = 0• 'one’ = 1• ‘two’ = 2• ‘three’ = 3

– An enumeration can have a maximum of 65,535 elements.

IS 257 – Fall 2009 2009.10.06 - SLIDE 40

MySQL Data Types

• The final string type (for this version) is a SET• A SET is a string object that can have zero or more

values, each of which must be chosen from a list of allowed values specified when the table is created.

• SET column values that consist of multiple set members are specified with members separated by commas (‘,’)

• For example, a column specified as SET('one', 'two') NOT NULL can have any of these values: – '' – 'one' – 'two' – 'one,two‘

• A set can have up to 64 member values and is stored as an 8byte number

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ALTER Table

• ALTER TABLE table-name ADD COLUMN col_name col_definition;

• … DROP COLUMN col_name;

• … CHANGE col_name new_col_definition;• Adds/removes a new column from an

existing database table• Many other options for adding constraints

(like NOT NULL, or PRIMARY KEY), etc.

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INSERT

• INSERT INTO table-name (attr1, attr4, attr5,…, attrK) VALUES (“val1”, val4, val5,…, “valK”);

• Adds a new row(s) to a table.• INSERT INTO table-name (attr1, attr4,

attr5,…, attrK) VALUES SELECT ...

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Creating a new table data from existing tables

• Syntax:– INSERT INTO tablename (attr1, attr2, attr3)

SELECT [DISTINCT] xattr1, xattr2, xattr3 FROM rel1 r1, rel2 r2,… rel3 r3 WHERE condition1 {AND | OR} condition2 ORDER BY attr1 [DESC], attr3 [DESC]

tablename has to previously exist for this to work in MySQL…

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DELETE

• DELETE FROM table-name WHERE <where clause>;

• Removes rows from a table.

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UPDATE

• UPDATE tablename SET attr1=newval, attr2 = newval2 WHERE <where clause>;

• changes values in existing rows in a table (those that match the WHERE clause).

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DROP Table

• DROP TABLE tablename;• Removes a table from the database.

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MySQL Demo

• MySQL is on “Harbinger” AKA “people”• Setup via My.SIMS• Unix command for interactive use is

‘mysql’ which needs to include ‘-p’ to be prompted for the password, and optionally includes your database name, e.g.:– mysql –p ray

• Note that the version on Dream is not the latest – it is currently V. 5.0.45, latest is 6.0

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Lecture Outline


• Introduction to SQL (continued)


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Database Applications

• Generally, end-users of database data probably do not want to learn SQL in order to access the information in the database

• Instead, they would prefer to use a familiar PC or Web interface that uses the graphical conventions and behaviors that they are familiar with

• Today we will look at PC –style client applications using systems like Access– Next time we will look at Web-based systems

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Query-by-Example

• QBE was developed in the 1970s as a simpler to use interface for IBM mainframe databases

• In QBE the user puts parts of what they want to get from the database into a form similar to what the output will look like

• The Query Design View in Access is an example of QBE

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Access Usability Hierarchy

API

VBA

MACROS

Functions/Expressions

Objects – Tables, queriesForms, Reports From McFadden

Chap. 10

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Examples

• Access OBJECT level– QBE querying

• Building Application interfaces– User wants “point and click” and forms to fill

in, not a Query editing screen or wizard– How to build them

• Drag and drop as in Access• Programming Languages• 4th Generation languages (more on these later)

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The MS JET Database EngineDatabase app Database app

Visual Basic Access Excel Word

Visual Basic for Applications (VBA)

Host Languages for the Jet DBMS

Data Access Objects (DAO)Includes DDL and DML

Jet Database Engine (Jet DBMS)

Jet Query Engine

InternalISAM

ReplicationEngine

DatabaseAdapted from Roman, “Access Database Design and Programming”

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Using Access for Applications

• Forms

• Reports

• Macros

• VBA programming

• Application framework

• HTML Pages

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Assignment 3

• Diveshop in MySQL– Look at instructions on the Assignments page– Or follow the phpMyAdmin instructions from

Kevin Heard’s tutorial

• New set of questions using the MySQL version of the Diveshop database – Download and install your own copy of the

database– Be sure to read each question carefully (make

sure when it says “rent” that you are looking at the correct prices, etc.

2009.10.06 - SLIDE 1IS 257 – Fall 2009 SQL and Client Applications University of California,...

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