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More on SQL (and MySQL)

More on SQL (and MySQL)

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More on SQL (and MySQL)

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  1. More on SQL (and MySQL) University of California, Berkeley School of Information IS 257: Database Management

  2. Lecture Outline • Review • ColdFusion • PHP • More on ORACLE SQL and SQL-Plus • MySQL

  3. Web Application Server Software • ColdFusion • PHP • ASP • All of the are server-side scripting languages that embed code in HTML pages

  4. ColdFusion • Developing WWW sites typically involved a lot of programming to build dynamic sites • e.g. Pages generated as a result of catalog searches, etc. • ColdFusion was designed to permit the construction of dynamic web sites with only minor extensions to HTML through a DBMS interface

  5. What ColdFusion is Good for • Putting up databases onto the Web • Handling dynamic databases (Frequent updates, etc) • Making databases searchable and updateable by users.

  6. Templates • Assume we have a database named contents_of_my_shopping_cart.mdb -- single table called contents... • Create an HTML page (uses extension .cfm), before <HEAD>... • <CFQUERY NAME= ”cart" DATASOURCE=“contents_of_my_shopping_cart"> SELECT * FROM contents ; </CFQUERY>

  7. Templates cont. • <HEAD> • <TITLE>Contents of My Shopping Cart</TITLE> • </HEAD> • <BODY> • <H1>Contents of My Shopping Cart</H1> • <CFOUTPUT QUERY= ”cart"> • <B>#Item#</B> <BR> • #Date_of_item# <BR> • $#Price# <P> • </CFOUTPUT> • </BODY> • </HTML>

  8. Templates cont. Contents of My Shopping Cart Bouncy Ball with Psychedelic Markings 12 December 1998 $0.25 Shiny Blue Widget 14 December 1998 $2.53 Large Orange Widget 14 December 1998 $3.75

  9. PHP • PHP is an Open Source Software project with many programmers working on the code. • Commonly paired with MySQL, another OSS project • Free • Both Windows and Unix support • Estimated that more than 250,000 web sites use PHP as an Apache Module.

  10. PHP Syntax • Similar to ASP • Includes most programming structures (Loops, functions, Arrays, etc.) • Loads HTML form variables so that they are addressable by name • <HTML><BODY> • <?php • $myvar = “Hello World”; • echo $myvar ; • ?> • </BODY></HTML>

  11. Combined with MySQL • DBMS interface appears as a set of functions: <HTML><BODY> <?php $db = mysql_connect(“localhost”, “root”); mysql_select_db(“mydb”,$db); $result = mysql_query(“SELECT * FROM employees”, $db); Printf(“First Name: %s <br>\n”, mysql_result($result, 0 “first”); Printf(“Last Name: %s <br>\n”, mysql_result($result, 0 “last”); ?></BODY></HTML>

  12. SELECT • Syntax: • SELECT [DISTINCT] attr1, attr2,…, attr3 as label, function(xxx), calculation, attr5, attr6 FROM relname1 r1, relname2 r2,… rel3 r3 WHERE condition1 {AND | OR} condition2 ORDER BY attr1 [DESC], attr3 [DESC]


  14. 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‘%wom_n%’ (Note different wild card) • IN (‘opt1’, ‘opt2’,…,’optn’)

  15. Aggregate Functions • COUNT(dataitem) • AVG(numbercolumn) • SUM(numbercolumn) • MAX(numbercolumn) • MIN(numbercolumn) • STDDEV(numbercolumn) • VARIANCE(numbercolumn)

  16. ABS(n) ACOS(n) ASIN(n) ATAN(n) ATAN2(n, m) CEIL(n) COS(n) COSH(n) ROUND(n) SIGN(n) SIN(n) SINH(n) SQRT(n) TAN(n) TANH(n) TRUNC(n[,m]) Numeric Functions • EXP(n) • EXP(n) • FLOOR(n) • LN(n) • LOG(m,n) • MOD(n) • POWER(m,n)

  17. CHR(n) CONCAT(char1,char2) INITCAP(char) LOWER(char) LPAD(char, n,char2), RPAD(char, n,char2) LTRIM(char, n, cset), RTRIM(char, n, cset) REPLACE(char, srch, repl) SOUNDEX(char) SUBSTR(char, m, n) SUBSTRB(char, m, n) TRANSLATE(char, from, to) UPPER(char) Character Functions returning character values

  18. ASCII(char) INSTR(char1, char2[,m, n]) INSTRB(char1, char2[,m, n]) LENGTH(char) LENGTHB(char) Character Function returning numeric values

  19. ADD_MONTHS(dt, n) LAST_DAY(d) MONTHS_BETWEEN(d1, d2) NEW_TIME(d, z1, z2) -- PST, AST, etc. NEXT_DAY(d, dayname) ROUND(d, fmt) -- century, year etc. SYSDATE TRUNC(d, fmt) -- century, year, etc. Date functions

  20. CHARTOROWID(char) CONVERT(char, dchar, schar) HEXTORAW(char) RAWTOHEX(raw) ROWIDTOCHAR(rowid) TO_CHAR (date, fmt) TO_DATE(char, fmt) TO_NUMBER(char,fmt) TO_MULTIBYTE(char) TO_SINGLE_BYTE(char) Conversion Functions

  21. Create Table • CREATE TABLE table-name (attr1 attr-type CONSTRAINT constr1 PRIMARY KEY, attr2 attr-type CONSTRAINT constr2 NOT NULL,…, attrM attr-type CONSTRAINT constr3 REFERENCES owner.tablename(attrname) ON DELETE CASCADE, attrN attr-type CONSTRAINT constrN CHECK (attrN = UPPER(attrN)), attrO attr-type DEFAULT default_value); • Adds a new table with the specified attributes (and types) to the database. • NOTE that the “CONSTRAINT and name parts are optional)

  22. Create Table • CREATE TABLE table-name ( attr1 attr-type PRIMARY KEY, attr2 attr-type NOT NULL, …, attrM attr-type REFERENCES owner.tablename(attrname) ON DELETE CASCADE, attrN attr-type CHECK (attrN = UPPER(attrN) attrO attr-type DEFAULT default_value); • Without “CONSTRAINT” and name parts

  23. Types • VARCHAR2(size) • NUMBER(p, s) • LONG -- long char data • DATE -- from 4712BC to 4714 AD • RAW(size) -- binary • LONG RAW -- large binary • ROWID -- row reference • CHAR(size) -- fixed length characters

  24. Alter Table • ALTER TABLE table-name ADD attr1 attr-type; • ALTER TABLE table-name ADD attr1 CONSTRAINT xxx constrainvalue; • ALTER TABLE table-name MODIFY attr1 optiontochange; • ALTER TABLE table-name DROP COLUMN attr1; • Adds, drops or modifies a column in an existing database table. • Note: constrainvalue is any column constraint like ‘PRIMARY KEY’, REFERENCES, etc.

  25. INSERT • INSERT INTO table-name (attr1, attr4, attr5,…, attrK) VALUES (“val1”, val4, val5,…, “valK”); • OR • INSERT INTO table-name SELECT col1, col2, col3as newcol2, col4 FROM xx, yy WHERE where-clause; • Adds a new row(s) to a table.

  26. DELETE • DELETE FROM table-name WHERE<where clause>; • Removes rows from a table.

  27. 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).

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

  29. CREATE INDEX • CREATE [ UNIQUE ] INDEX indexname ON tablename (attr1 [ASC|DESC][, attr2 [ASC|DESC], ...]) • Adds an index on the specified attributes to a table

  30. System Information In ORACLE • Find all of the tables for a user • SELECT * FROM ALL_CATALOG WHERE OWNER = ‘userid’; • SELECT * FROM USER_CATALOG; (or CAT) • Show the attributes and types of data for a particular table in SQLPlus • DESCRIBE tablename;

  31. Running commands • Create file with SQL and SQLPlus commands in it. • Use a plain text editor and NOT a word processor (or save as text only) • Give the file the extension .sql • From inside SQLPlus type • START filename

  32. Simple formatting in SQLPlus • SET PAGESIZE 500 • SET LINESIZE 79 • PROMPT stuff to put out to screen • TTITLE “title to put at top of results pages” • COLUMN col_name HEADING “New Name”

  33. Outputting results as a file… • SPOOL filename • Commands • everything that you see is copied to the file until… • SPOOL STOP • File will be created with everything between the SPOOL commands

  34. Lecture Outline • Review • ColdFusion • PHP • More on ORACLE SQL and SQL-Plus • MySQL

  35. MySQL • The tag-line at 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 ) • • Ticketmaster • Yahoo! • The US Census bureau • and many, many others

  36. MySQL myths • The 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

  37. MySQL documentation • MySQL is available for download from • 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

  38. 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)

  39. 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

  40. 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

  41. 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

  42. 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.

  43. 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

  44. MySQL Demo • MySQL is on Dream, like ORACLE • 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 ray –p • Note that the version on Dream is not the latest – it is currently V. 3.23.58, latest is 5.1