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From: <sub...@co...> - 2004-11-12 04:47:12
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Author: ianb Date: 2004-11-11 13:57:53 -0500 (Thu, 11 Nov 2004) New Revision: 364 Modified: trunk/SQLObject/docs/presentation-2004-11/sqlobject-and-database-progr= amming.html trunk/SQLObject/docs/presentation-2004-11/ui/custom.css trunk/SQLObject/docs/presentation-2004-11/ui/framing.css trunk/SQLObject/docs/presentation-2004-11/ui/pretty.css Log: Edits and visual updates Modified: trunk/SQLObject/docs/presentation-2004-11/sqlobject-and-databas= e-programming.html =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- trunk/SQLObject/docs/presentation-2004-11/sqlobject-and-database-prog= ramming.html 2004-11-11 18:38:24 UTC (rev 363) +++ trunk/SQLObject/docs/presentation-2004-11/sqlobject-and-database-prog= ramming.html 2004-11-11 18:57:53 UTC (rev 364) @@ -11,7 +11,7 @@ <link rel=3D"stylesheet" href=3D"ui/print.css" type=3D"text/css" media=3D"print" id=3D"slidePrint" /> <link rel=3D"stylesheet" href=3D"ui/custom.css" type=3D"text/css"/> -<sc ript src=3D"ui/slides.js" type=3D"text/javascript"></script> +<script src=3D"ui/slides.js" type=3D"text/javascript"></script> </head> <body> =20 @@ -62,7 +62,7 @@ <!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> =20 <div class=3D"slide"> -<h1>Database Programming in Python</h1> +<h1>The DB API</h1> =20 <p>Database programming in Python is based on the <b><a href=3D"http://www.python.org/peps/pep-0249.html">DB-API</a></b>. @@ -72,11 +72,9 @@ <li>MySQL</li> <li>PostgreSQL (multiple drivers)</li> <li>SQLite</li> -<li>Oracle</li> -<li>Sybase</li> <li>Firebird (Interbase)</li> <li>MAXDB (SAP DB)</li> -<li>MS SQL Server</li> +<li>Oracle, Sybase, MS SQL Server</li> </p> </div> =20 @@ -109,7 +107,7 @@ <h1>DB API</h1> =20 <ul> -<li> Import the databse module (<code>MySQLdb</code>, +<li> Import the database module (<code>MySQLdb</code>, <code>psycopg</code>, <code>sqlite</code>, etc) </li> <li> Use <code>module.connect(...)</code> to create a connection. </li> @@ -194,12 +192,14 @@ =20 <div class=3D"slide"> =20 -<h1>Object-Relational Mappers: Classes</h1> +<h1>ORMs: Classes</h1> =20 <p> =20 The class: =20 +<table width=3D"100%"> +<tr><td> <table border=3D1> =20 <tr class=3D"code-accent"><th colspan=3D3>person</th></tr> @@ -225,14 +225,16 @@ </tr> =20 </table> -<p> +</td> =20 +<td> <pre> class Person(SQLObject): <span class=3D"comment"># id is implicit</span> first_name =3D StringCol() last_name =3D StringCol() </pre> +</td></tr></table> =20 </div> =20 @@ -241,12 +243,15 @@ =20 <div class=3D"slide"> =20 -<h1>Object-Relational Mappers: Instances</h1> +<h1>ORMs: Instances</h1> =20 <p> =20 An instance: =20 +<table width=3D"100%"> +<tr><td> + <table border=3D1> =20 <tr><th colspan=3D3>person</th></tr> @@ -272,13 +277,17 @@ </tr> =20 </table> -<p> =20 +</td><td> + <pre> -john =3D Person.get(1) -assert john.first_name =3D=3D <span class=3D"string">'John'</span> +<span class=3D"prompt">>>></span> john =3D Person.get(1) +<span class=3D"prompt">>>></span> john.first_name +<span class=3D"output">'John'</span> </pre> =20 +</td></tr></table> +</p> =20 </div> =20 @@ -286,7 +295,7 @@ =20 =20 <div class=3D"slide"> -<h1>Object-Relational Mapping: summary</h1> +<h1>ORM: summary</h1> =20 <ul> <li>Every table is a class</li> @@ -308,10 +317,32 @@ first_name =3D StringCol() last_name =3D StringCol() emails =3D MultipleJoin('Email') +</pre> + +</div> + +<!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> + + +<div class=3D"slide"> +<h1>Usage (classes)</h1> + +<pre> class Email(SQLObject): person =3D ForeignKey(<span class=3D"string">'Person'</span>) type =3D EnumCol(['home', 'work']) address =3D StringCol() +</pre> + +</div> + +<!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> + + +<div class=3D"slide"> +<h1>Usage (creating tables)</h1> + +<pre> def createTables(): for table in (Person, Email): table.createTable(ifNotExists=3DTrue) @@ -322,7 +353,7 @@ <!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> =20 <div class=3D"slide"> -<h1>More use...</h1> +<h1>Usage (instances)</h1> =20 Using your classes: =20 @@ -332,6 +363,17 @@ <span class=3D"prompt">...</span> address=3D<span class=3D"string">'= jo...@wo...'</span>) <span class=3D"prompt">>>></span> john.emails <span class=3D"output">[]</span> +</pre> + +</div> + +<!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> + + +<div class=3D"slide"> +<h1>Usage (instances)</h1> + +<pre> <span class=3D"prompt">>>></span> tom =3D Person(first_name=3D<= span class=3D"string">'Tom'</span>, last_name=3D<span class=3D"string">'J= ones'</span>) <span class=3D"prompt">>>></span> tom is Person.get(tom.id) <span class=3D"output">True</span> @@ -342,8 +384,6 @@ </div> =20 =20 - - <!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> =20 =20 @@ -373,13 +413,17 @@ return self.first_name + ' ' + self.last_name </pre> =20 +<pre> +<span class=3D"prompt">>>></span> tom.name +<span class=3D"output">'Tom Jones'</span> +</pre> =20 </div> =20 <!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> =20 <div class=3D"slide"> -<h1></h1> +<h1>Automatic properties</h1> =20 <ul> <li> <code>_get_attr()</code> methods are called whenever the @@ -487,36 +531,38 @@ <!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> =20 <div class=3D"slide"> -<h1>Lazy classes</h1> +<h1>Many-to-many...</h1> =20 <p> -SQLObject can use reflection to figure out what columns your table -has: +The intermediate table created: =20 <pre> -class Person(SQLObject): - _fromDatabase =3D True +CREATE TABLE address_person ( + address_id INT NOT NULL, + person_id INT NOT NULL +); </pre> - </p> =20 </div> =20 <!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> =20 - <div class=3D"slide"> -<h1>Many-to-many...</h1> +<h1>Lazy classes</h1> =20 <p> -The intermediate table created: +SQLObject can use reflection to figure out what columns your table +has: =20 <pre> -CREATE TABLE address_person ( - address_id INT NOT NULL, - person_id INT NOT NULL -); +class Person(SQLObject): + _fromDatabase =3D True </pre> + +You can start with <code>_fromDatabase =3D True</code> and add=20 +in explicit columns, overriding defaults. + </p> =20 </div> @@ -524,6 +570,7 @@ <!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> =20 =20 + <div class=3D"slide"> <h1>Instances</h1> =20 @@ -542,12 +589,13 @@ <h1>Updating</h1> =20 <ul> -<li>Use <code>aPerson.first_name =3D <span -class=3D"string">"new_name"</span></code></li> -<li>Use <code>aPerson.set(first_name=3D<span +<li><code>aPerson.first_name =3D <span +class=3D"string">"new_name"</span></code><br> + <code class=3D"sql">UPDATE</code> is executed immediately </li> +<li> Update multiple columns at once: <br> +<code>aPerson.set(first_name=3D<span class=3D"string">"new_fname"</span>, last_name=3D<span -class=3D"string">"new_lname"</span>)</code> for multiple simultaneous -updates. </li> +class=3D"string">"new_lname"</span>)</code> </li> </ul> =20 </div> @@ -580,7 +628,7 @@ <p> =20 <ul> -<li><code>Class.<b>q</b>.<i>column_name</i></code> creates a magical +<li><code>Class.<b style=3D"color: #990000">q</b>.column_name</code> cre= ates a magical object that creates queries.</li> <li><code>sqlrepr()</code> turns these query objects into SQL (mostly hidden)</li> @@ -625,13 +673,13 @@ <div class=3D"slide"> <h1>SelectResult</h1> =20 -Select results are fancy. +Select results are more than just lists: =20 <ul> <li> You can slice them, and <code class=3D"sql">LIMIT</code> and <code class=3D"sql">OFFSET</code> statements are added to your query</li> <li> You can iterate through them, and avoid loading all objects into -memory</li> +memory </li> <li> You can do things like <code>select_result.count()</code> to run aggregate functions </li> <li> To get a real list, you must do <code>list(select_result)</code></l= i> @@ -673,16 +721,14 @@ =20 <!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> =20 - <div class=3D"slide"> -<h1>Solving the question by avoidance</h1> +<h1>The problem with ORMs</h1> =20 -<ul> - <li> SQLObject doesn't let you forget SQL </li> - <li> You still have to think relationally </li> - <li> But many relational concepts don't work either </li> - <li> Advantage: it's easy </li> -</ul> +<p> +ORMs live in the world between Object Oriented programmers (and +programs) and Relational programmers (and programs). Neither will be +happy. +</p> =20 </div> =20 @@ -695,8 +741,6 @@ <ul> <li> Python classes aren't tables</li> <li> Python instances aren't rows</li> - <li> Primitive values (like <code class=3D"string">"John"</code>) - aren't part of the ORM at all </li> <ul> =20 </div> @@ -711,7 +755,7 @@ <li> Databases don't have inheritance </li> <li> Even when they do, no one uses it </li> <li> Some tables are too boring (e.g., intermediate tables for - many-to-many relationships) </li> + many-to-many relationships), or don't warrant the overhead </li> </ul> =20 </div> @@ -723,7 +767,8 @@ =20 <ul> <li> Instances get garbage collected, rows are forever </li> - <li> Instances can't be pre-allocated </li> + <li> Rows exist even when instances don't </li> + <li> Instances may still exist when the row is gone </li> <li> In the relational calculus, rows don't have real identity </li> =20 </div> @@ -738,13 +783,29 @@ <li> Things like joins don't make sense for objects, but are central to relations </li> <li> Views and stored procedures also don't make sense </li> + <li> Aggregate functions and set operations aren't natural in Python=20 + (the <code>for</code> loop is natural) </li> </ul> =20 </div> =20 <!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> =20 +<div class=3D"slide"> +<h1>Solving the question by avoidance</h1> =20 +<ul> + <li> SQLObject doesn't let you forget SQL </li> + <li> You still have to think relationally </li> + <li> But many relational concepts don't work either </li> + <li> Advantage: it's easy </li> +</ul> + +</div> + +<!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> + + <div class=3D"slide"> <h1>Solving the Mismatch</h1> =20 @@ -753,17 +814,50 @@ <ul> <li> There exist database restrictions; not every database schema maps well. (But most are fine) </li> + <li> Sometimes you have to do things more slowly or more imperatively, + compared to a purely relational technique </li> <li> There exist object restrictions; not every object-oriented - concept maps well; e.g., no inheritance. </li> + concept maps well; e.g., no inheritance </li> + <li> Inheritance isn't planned; this isn't transparent persistence </li= > </ul> =20 </div> =20 <!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> =20 +<div class=3D"slide"> +<h1>Some other alternatives</h1> =20 +Several Python ORMs exist; contrasts:=20 +<ul> + <li> SQLObject doesn't try to be too OO, so it works well with normal=20 + database schemas </li> + <li> SQLObject doesn't have a compile step </li> + <li> SQLObject isn't <i>just</i> a SQL wrapper </li> + <li> SQLObject is reasonably complete </li> +</ul> =20 </div> =20 +<!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> + + +<div class=3D"slide"> +<h1>Other alternatives...</h1> + +<p> + +See the Python Wiki at: <a href=3D"http://python.org/moin">python.org/mo= in</a><br> +The page is <a href=3D"http://python.org/moin/HigherLevelDatabaseProgram= ming">HigherLevelDatabaseProgramming</a>. +</p> + +</div> + +<!-- =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --> + + + +</div> + </body> </html> Modified: trunk/SQLObject/docs/presentation-2004-11/ui/custom.css =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- trunk/SQLObject/docs/presentation-2004-11/ui/custom.css 2004-11-11 18= :38:24 UTC (rev 363) +++ trunk/SQLObject/docs/presentation-2004-11/ui/custom.css 2004-11-11 18= :57:53 UTC (rev 364) @@ -1,3 +1,7 @@ +td { + vertical-align: top; +} + .string {=20 color: #006600; } @@ -16,7 +20,7 @@ } =20 .sql {=20 - color: #006600; + color: #004466; font-weight: bold; } =20 Modified: trunk/SQLObject/docs/presentation-2004-11/ui/framing.css =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- trunk/SQLObject/docs/presentation-2004-11/ui/framing.css 2004-11-11 1= 8:38:24 UTC (rev 363) +++ trunk/SQLObject/docs/presentation-2004-11/ui/framing.css 2004-11-11 1= 8:57:53 UTC (rev 364) @@ -4,15 +4,15 @@ to help you with the rearrangement process. */ =20 div#header, div#footer, div.slide {width: 100%; top: 0; left: 0;} -div#header {top: 0; height: 3em; z-index: 1;} -div#footer {top: auto; bottom: 0; height: 2.5em; z-index: 5;} +div#header {top: 0; height: 2em; z-index: 1;} +div#footer {top: auto; bottom: 0; height: 1.75em; z-index: 5;} div.slide {top: 0; width: 92%; padding: 3.5em 4% 4%; z-index: 2;} div#controls {left: 50%; top: 0; width: 50%; height: 100%; z-index: 1;} #footer>div#controls {bottom: 0; top: auto; height: auto;} =20 div#controls form {position: absolute; bottom: 0; right: 0; width: 100%; margin: 0;} -#currentSlide {position: absolute; width: 10%; left: 45%; bottom: 1em; z= -index: 10;} +#currentSlide {position: absolute; width: 10%; left: 45%; bottom: 1.5em;= z-index: 10;} html>body #currentSlide {position: fixed;} =20 /* Modified: trunk/SQLObject/docs/presentation-2004-11/ui/pretty.css =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- trunk/SQLObject/docs/presentation-2004-11/ui/pretty.css 2004-11-11 18= :38:24 UTC (rev 363) +++ trunk/SQLObject/docs/presentation-2004-11/ui/pretty.css 2004-11-11 18= :57:53 UTC (rev 364) @@ -2,7 +2,8 @@ Note that the 'body' font size may have to be changed if the resoluti= on is different than expected. */ =20 -body {background: #fff url(bodybg.gif) -16px 0 no-repeat; color: #000; f= ont-size: 2em;} +/* url(bodybg.gif) */ +body {background: #fff -16px 0 no-repeat; color: #000; font-size: 2em;} :link, :visited {text-decoration: none;} #controls :active {color: #88A !important;} #controls :focus {outline: 1px dotted #227;} @@ -31,17 +32,17 @@ ul ul li {margin: .2em; font-size: 85%; list-style: square;} img.leader {display: block; margin: 0 auto;} =20 -div#header, div#footer {background: #005; color: #AAB; +div#header, div#footer {background: #005; color: #BBC; font-family: Verdana, Helvetica, sans-serif;} -div#header {background: #005 url(bodybg.gif) -16px 0 no-repeat; +div#header {background: #005 -16px 0 no-repeat; line-height: 1px;} div#footer {font-size: 0.5em; font-weight: bold; padding: 1em 0;} #footer h1, #footer h2 {display: block; padding: 0 1em;} #footer h2 {font-style: italic;} =20 div.long {font-size: 0.75em;} -.slide h1 {position: absolute; top: 0.7em; left: 87px; z-index: 1; - margin: 0; padding: 0.3em 0 0 50px; white-space: nowrap; +.slide h1 {position: absolute; top: 0.0em; left: 0px; z-index: 1; + margin: 0; padding: 0.3em 0 0 10px; white-space: nowrap; font: bold 150%/1em Helvetica, sans-serif; text-transform: capitalize; color: #DDE; background: #005;} .slide h3 {font-size: 130%;} @@ -54,13 +55,13 @@ top: auto; height: auto;} div#controls form {position: absolute; bottom: 0; right: 0; width: 100%; margin: 0; padding: 0;} -div#controls a {font-size: 2em; padding: 0; margin: 0 0.5em;=20 +div#controls a {font-size: 1.7em; padding: 0; margin: 0 0.5em;=20 background: #005; border: none; color: #779;=20 cursor: pointer;} div#controls select {visibility: hidden; background: #DDD; color: #227;} div#controls div:hover select {visibility: visible;} =20 -#currentSlide {text-align: center; font-size: 0.5em; color: #449;} +#currentSlide {text-align: center; font-size: 0.5em; color: #77B;} =20 #slide0 {padding-top: 3.5em; font-size: 90%;} #slide0 h1 {position: static; margin: 1em 0 1.33em; padding: 0; |
