SLIDE 1IS Fall 2002 Relational Algebra and Calculus: Introduction to SQL University of California, Berkeley School of Information Management and Systems SIMS 257: Database Management

SLIDE 2IS Fall 2002 Lecture Outline Review –Design to Relational Implementation Relational Operations Relational Algebra Relational Calculus Introduction to SQL

SLIDE 3IS Fall 2002 Lecture Outline Review –Design to Relational Implementation Relational Operations Relational Algebra Relational Calculus Introduction to SQL

SLIDE 4IS Fall 2002 Database Design Process Conceptual Model Logical Model External Model Conceptual requirements Conceptual requirements Conceptual requirements Conceptual requirements Application 1 Application 2Application 3Application 4 Application 2 Application 3 Application 4 External Model External Model External Model Internal Model

SLIDE 5IS Fall 2002 Cookie ER Diagram AU_ID BIBFILE pubid LIBFILE INDXFILE accno SUBFILE libid CALLFILE pubid PUBFILE subcodeaccnosubcode libid accno AUTHORS AU_BIB accno AU ID Author Note: diagram contains only attributes used for linking

SLIDE 6IS Fall 2002 What Problems? What sorts of problems and missing features arise given the previous ER diagram?

SLIDE 7IS Fall 2002 Problems Identified Subtitles, parallel titles? Edition information Series information lending status material type designation Genre, class information Better codes (ISBN?) Missing information (ISBN) Authority control for authors Missing/incomplete data Data entry problems Ordering information Illustrations Subfield separation (such as last_name, first_name) Separate personal and corporate authors

SLIDE 8IS Fall 2002 Problems (Cont.) Location field inconsistent No notes field No language field Zipcode doesn’t support plus-4 No publisher shipping addresses No (indexable) keyword search capability No support for multivolume works No support for URLs –to online version –to libraries –to publishers

SLIDE 9IS Fall 2002 Original Cookie ER Diagram AU_ID BIBFILE pubid LIBFILE INDXFILE accno SUBFILE libid CALLFILE pubid PUBFILE subcodeaccnosubcode libid accno AUTHORS AU_BIB accno AU ID Author Note: diagram contains only attributes used for linking

SLIDE 10IS Fall 2002 nameid BIBFILE pubid LIBFILE INDXFILE accno SUBFILE libid CALLFILE pubid PUBFILE subcodeaccnosubcode libid accno AUTHFILE AUTHBIB authtype accno nameid name Cookie2: Separate Name Authorities

SLIDE 11IS Fall 2002 Cookie 3: Keywords nameid BIBFILE pubid LIBFILE INDXFILE accno SUBFILE libid CALLFILE pubid PUBFILE subcodeaccnosubcode libid accno AUTHFILE AUTHBIB authtype accno nameid name KEYMAP TERMS accnotermid

SLIDE 12IS Fall 2002 Cookie 4: Series nameid BIBFILE pubid LIBFILE INDXFILE accno SUBFILE libid CALLFILE pubid PUBFILE subcodeaccnosubcode libid accno AUTHFILE AUTHBIB authtype accno nameid name KEYMAP TERMS accnotermid SERIES seriesid ser_title

SLIDE 13IS Fall 2002 Cookie 5: Circulation nameid BIBFILE pubid LIBFILE accno libid CALLFILE pubid PUBFILE libid accno INDXFILE SUBFILE subcodeaccno subcode AUTHFILE AUTHBIB authtype accno nameid name KEYMAP TERMS accnotermid SERIES seriesid ser_title CIRC circidcopynumpatronid PATRON circid

SLIDE 14IS Fall 2002 Logical Model: Mapping to Relations Take each entity –BIBFILE –LIBFILE –CALLFILE –SUBFILE –PUBFILE –INDXFILE And make it a table...

SLIDE 15IS Fall 2002 Lecture Outline Review –Design to Relational Implementation Relational Operations Relational Algebra Relational Calculus Introduction to SQL

SLIDE 16IS Fall 2002 Relational Algebra Operations Select Project Product Union Intersect Difference Join Divide

SLIDE 17IS Fall 2002 Select Extracts specified tuples (rows) from a specified relation (table).

SLIDE 18IS Fall 2002 Project Extracts specified attributes(columns) from a specified relation.

SLIDE 19IS Fall 2002 Product Builds a relation from two specified relations consisting of all possible concatenated pairs of tuples, one from each of the two relations. (AKA Cartesian Product) abcabc xyxy xyxyxyxyxyxy aabbccaabbcc Product

SLIDE 20IS Fall 2002 Union Builds a relation consisting of all tuples appearing in either or both of two specified relations.

SLIDE 21IS Fall 2002 Intersect Builds a relation consisting of all tuples appearing in both of two specified relations

SLIDE 22IS Fall 2002 Difference Builds a relation consisting of all tuples appearing in first relation but not the second.

SLIDE 23IS Fall 2002 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 B1 A2 B1 A3 B2 B1 C1 B2 C2 B3 C3 A1 B1 C1 A2 B1 C1 A3 B2 C2 (Natural or Inner) Join

SLIDE 24IS Fall 2002 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 B1 A2 B1 A3 B2 A4 B7 B1 C1 B2 C2 B3 C3 A1 B1 C1 A2 B1 C1 A3 B2 C2 A4 * * Outer Join

SLIDE 25IS Fall 2002 Divide Takes two relations, one binary and one unary, and builds a relation consisting of all values of one attribute of the binary relation that match (in the other attribute) all values in the unary relation. a xyxy xyzxyxyzxy aaabcaaabc Divide

SLIDE 26IS Fall 2002 ER Diagram: Acme Widget Co. Contains Part Part#Count Price Customer Quantity Orders Cust# Invoice Writes Sales-Rep Invoice# Sales Rep# Line-Item Contains Part# Invoice# Cust# Hourly Employee ISA Emp# Wage

SLIDE 27IS Fall 2002 Employee

SLIDE 28IS Fall 2002 Part

SLIDE 29IS Fall 2002 Sales-Rep Hourly

SLIDE 30IS Fall 2002 Customer

SLIDE 31IS Fall 2002 Invoice

SLIDE 32IS Fall 2002 Line-Item

SLIDE 33IS Fall 2002 Join Items

SLIDE 34IS Fall 2002 Lecture Outline Review –Design to Relational Implementation Relational Operations Relational Algebra Relational Calculus Introduction to SQL

SLIDE 35IS Fall 2002 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

SLIDE 36IS Fall 2002 Lecture Outline Review –Design to Relational Implementation Relational Operations Relational Algebra Relational Calculus Introduction to SQL

SLIDE 37IS Fall 2002 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.

SLIDE 38IS Fall 2002 Lecture Outline Review –Design to Relational Implementation Relational Operations Relational Algebra Relational Calculus Introduction to SQL

SLIDE 39IS Fall 2002 SQL Structured Query Language Database Definition and Querying Basic language is standardized across relational DBMSs. Each system may have proprietary extensions to standard. Relational Calculus combines Select, Project and Join operations in a single command. SELECT.

SLIDE 40IS Fall 2002 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.

SLIDE 41IS Fall 2002 SQL99 In 1999, SQL99 – also known as SQL3 – was adopted and contains the following eight parts: –The SQL/Framework (75 pages) –SQL/Foundation (1100 pages) –SQL/Call Level Interface (400 pages) –SQL/Persistent Stored Modules (PSM) (160 pages) –SQL/Host Language Bindings (250 pages) –SQL Transactions (??) –SQL Temporal objects (??) –SQL Objects (??) Designed to be compatible with SQL92

SLIDE 42IS Fall 2002 SQL99 The SQL/Framework --SQL basic concepts and general requirements. SQL/Call Level Interface (CLI) -- An API for SQL. This is similar to ODBC. SQL/Foundation --The syntax and SQL operations that are the basis for the language.

SLIDE 43IS Fall 2002 SQL99 SQL/Persistent Stored Modules (PSM) -- Defines the rules for developing SQL routines, modules, and functions such as those used by stored procedures and triggers. This is implemented in many major RDBMSs through proprietary, nonportable languages, but for the first time we have a standard for writing procedural code that is transportable across databases.

SLIDE 44IS Fall 2002 SQL99 SQL/Host Language Bindings --Define ways to code embedded SQL in standard programming languages. This simplifies the approach used by CLIs and provides performance enhancements. SQL Transactions --Transactional support for RDBMSs. SQL Temporal objects --Deal with Time-based data. SQL Objects --The new Object-Relational features, which represent the largest and most important enhancements to this new standard.

SLIDE 45IS Fall 2002 SQL99 Data Types SQL Data Types Ref Types Predefined Types Arrays ROW Data Struct User-Defined Types NumericStringDateTimeIntervalBoolean Date Time Timestamp BitCharacterBlob Fixed Varying CLOB Fixed Varying ApproximateExact NEW IN SQL99

SLIDE 46IS Fall 2002 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

SLIDE 47IS Fall 2002 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]

SLIDE 48IS Fall 2002 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...

SLIDE 49IS Fall 2002 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

SLIDE 50IS Fall 2002 Relational Algebra Selection using SELECT Syntax: –SELECT * WHERE condition1 {AND | OR} condition2;

SLIDE 51IS Fall 2002 Relational Algebra Projection using SELECT Syntax: –SELECT [DISTINCT] attr1, attr2,…, attr3 FROM rel1 r1, rel2 r2,… rel3 r3;

SLIDE 52IS Fall 2002 Relational Algebra Join using SELECT Syntax: –SELECT * FROM rel1 r1, rel2 r2 WHERE r1.linkattr = r2.linkattr ;

SLIDE 53IS Fall 2002 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

SLIDE 54IS Fall 2002 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.

SLIDE 55IS Fall 2002 Aggregate Functions Count Avg SUM MAX MIN Others may be available in different systems

SLIDE 56IS Fall 2002 Using Aggregate functions SELECT attr1, Sum(attr2) AS name FROM tab1, tab2... GROUP BY attr1, attr3 HAVING condition;

SLIDE 57IS Fall 2002 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"));

SLIDE 58IS Fall 2002 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

SLIDE 59IS Fall 2002 Create Table CREATE TABLE table-name (attr1 attr- type PRIMARYKEY, attr2 attr-type,…,attrN attr-type); Adds a new table with the specified attributes (and types) to the database.

SLIDE 60IS Fall 2002 Access Data Types 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 chars)

SLIDE 61IS Fall 2002 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 E38 to – E–45 for negative values and from E–45 to E38 for positive values.4 bytes Double –Stores numbers from – E308 to – E–324 for negative values and from E308 to E–324 for positive values.158 bytes Replication ID –Globally unique identifier (GUID)N/A16 bytes

SLIDE 62IS Fall 2002 Oracle Data Types CHAR (size) -- max 2000 VARCHAR2(size) -- up to 4000 DATE DECIMAL, FLOAT, INTEGER, INTEGER(s), SMALLINT, NUMBER, NUMBER(size,d) –All numbers internally in same format… LONG, LONG RAW, LONG VARCHAR –up to 2 Gb -- only one per table BLOB, CLOB, NCLOB -- up to 4 Gb BFILE -- file pointer to binary OS file

SLIDE 63IS Fall 2002 Creating a new table from existing tables Syntax: –SELECT [DISTINCT] attr1, attr2,…, attr3 INTO newtablename FROM rel1 r1, rel2 r2,… rel3 r3 WHERE condition1 {AND | OR} condition2 ORDER BY attr1 [DESC], attr3 [DESC]

SLIDE 64IS Fall 2002 Alter Table ALTER TABLE table-name ADD COLUMN attr1 attr-type; … DROP COLUMN attr1; Adds a new column to an existing database table.

SLIDE 65IS Fall 2002 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...

SLIDE 66IS Fall 2002 DELETE DELETE FROM table-name WHERE ; Removes rows from a table.

SLIDE 67IS Fall 2002 UPDATE UPDATE tablename SET attr1=newval, attr2 = newval2 WHERE ; changes values in existing rows in a table (those that match the WHERE clause).

SLIDE 68IS Fall 2002 DROP Table DROP TABLE tablename; Removes a table from the database.

SLIDE 69IS Fall 2002 CREATE INDEX CREATE [ UNIQUE ] INDEX indexname ON tablename (attr1 [ASC|DESC][, attr2 [ASC|DESC],...]) [WITH { PRIMARY | DISALLOW NULL | IGNORE NULL }]