SLIDE 1IS 257 – Spring 2004 SQL and Client Applications University of California, Berkeley School of Information Management and Systems SIMS 257: Database Management

SLIDE 2IS 257 – Spring 2004 Lecture Outline Review –Relational Operations –Relational Algebra –Relational Calculus –Introduction to SQL Introduction to SQL (continued) Application Development in Access

SLIDE 3IS 257 – Spring 2004 Lecture Outline Review –Relational Operations –Relational Algebra –Relational Calculus –Introduction to SQL Introduction to SQL (continued) Application Development in Access

SLIDE 4IS 257 – Spring 2004 Relational Algebra Operations Select Project Product Union Intersect Difference Join Divide

SLIDE 5IS 257 – Spring 2004 Select Extracts specified tuples (rows) from a specified relation (table).

SLIDE 6IS 257 – Spring 2004 Project Extracts specified attributes(columns) from a specified relation.

SLIDE 7IS 257 – Spring 2004 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 8IS 257 – Spring 2004 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 9IS 257 – Spring 2004 Join Items

SLIDE 10IS 257 – Spring 2004 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 11IS 257 – Spring 2004 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 12IS 257 – Spring 2004 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 13IS 257 – Spring 2004 Lecture Outline Review –Relational Operations –Relational Algebra –Relational Calculus –Introduction to SQL Introduction to SQL (continued) Application Development in Access

SLIDE 14IS 257 – Spring 2004 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 15IS 257 – Spring 2004 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 16IS 257 – Spring 2004 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 17IS 257 – Spring 2004 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 18IS 257 – Spring 2004 Relational Algebra Selection using SELECT Syntax: –SELECT * WHERE condition1 {AND | OR} condition2;

SLIDE 19IS 257 – Spring 2004 Relational Algebra Projection using SELECT Syntax: –SELECT [DISTINCT] attr1, attr2,…, attr3 FROM rel1 r1, rel2 r2,… rel3 r3;

SLIDE 20IS 257 – Spring 2004 Relational Algebra Join using SELECT Syntax: –SELECT * FROM rel1 r1, rel2 r2 WHERE r1.linkattr = r2.linkattr ;

SLIDE 21IS 257 – Spring 2004 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 22IS 257 – Spring 2004 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 23IS 257 – Spring 2004 Aggregate Functions Count Avg SUM MAX MIN Others may be available in different systems

SLIDE 24IS 257 – Spring 2004 Using Aggregate functions SELECT attr1, Sum(attr2) AS name FROM tab1, tab2... GROUP BY attr1, attr3 HAVING condition;

SLIDE 25IS 257 – Spring 2004 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 26IS 257 – Spring 2004 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 27IS 257 – Spring 2004 Lecture Outline Review –Relational Operations –Relational Algebra –Relational Calculus –Introduction to SQL Introduction to SQL (continued) Application Development in Access

SLIDE 28IS 257 – Spring 2004 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 29IS 257 – Spring 2004 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 30IS 257 – Spring 2004 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 31IS 257 – Spring 2004 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 32IS 257 – Spring 2004 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 33IS 257 – Spring 2004 ALTER Table ALTER TABLE table-name ADD COLUMN attr1 attr-type; … DROP COLUMN attr1; Adds a new column to an existing database table.

SLIDE 34IS 257 – Spring 2004 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 35IS 257 – Spring 2004 DELETE DELETE FROM table-name WHERE ; Removes rows from a table.

SLIDE 36IS 257 – Spring 2004 UPDATE UPDATE tablename SET attr1=newval, attr2 = newval2 WHERE ; changes values in existing rows in a table (those that match the WHERE clause).

SLIDE 37IS 257 – Spring 2004 DROP Table DROP TABLE tablename; Removes a table from the database.

SLIDE 38IS 257 – Spring 2004 CREATE INDEX CREATE [ UNIQUE ] INDEX indexname ON tablename (attr1 [ASC|DESC][, attr2 [ASC|DESC],...]) [WITH { PRIMARY | DISALLOW NULL | IGNORE NULL }]

SLIDE 39IS 257 – Spring 2004 Lecture Outline Review –Relational Operations –Relational Algebra –Relational Calculus –Introduction to SQL Introduction to SQL (continued) Application Development in Access

SLIDE 40IS 257 – Spring 2004 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

SLIDE 41IS 257 – Spring 2004 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

SLIDE 42IS 257 – Spring 2004 Access Usability Hierarchy API VBA MACROS Functions/Expressions Objects – Tables, queries Forms, Reports From McFadden Chap. 10

SLIDE 43IS 257 – Spring 2004 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 4 th Generation languages (more on these later)

SLIDE 44IS 257 – Spring 2004 The MS JET Database Engine Database app Visual BasicAccessExcelWord 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 Internal ISAM Replication Engine Database Adapted from Roman, “Access Database Design and Programming”

SLIDE 45IS 257 – Spring 2004 Using Access for Applications Forms Reports Macros VBA programming Application framework HTML Pages