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Posted to cvs@cocoon.apache.org by jo...@apache.org on 2003/10/14 23:41:58 UTC
cvs commit: cocoon-2.1/src/documentation/xdocs/userdocs/transformers book.xml sql-transformer.xml
joerg 2003/10/14 14:41:58
Modified: src/documentation/xdocs/userdocs/transformers book.xml
sql-transformer.xml
Log:
code formatting, style in the page, sqltransformer is not a core transformer
Revision Changes Path
1.5 +1 -1 cocoon-2.1/src/documentation/xdocs/userdocs/transformers/book.xml
Index: book.xml
===================================================================
RCS file: /home/cvs/cocoon-2.1/src/documentation/xdocs/userdocs/transformers/book.xml,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- book.xml 12 Oct 2003 15:19:27 -0000 1.4
+++ book.xml 14 Oct 2003 21:41:58 -0000 1.5
@@ -20,7 +20,6 @@
<menu-item label="Fragment Extractor Transformer" href="extractor-transformer.html"/>
<menu-item label="I18n Transformer" href="i18n-transformer.html"/>
<menu-item label="Log Transformer" href="log-transformer.html"/>
- <menu-item label="SQL Transformer" href="sql-transformer.html"/>
<menu-item label="Filter Transformer" href="filter-transformer.html"/>
<menu-item label="Read DOM Session Transformer" href="readdomsession-transformer.html"/>
<menu-item label="Write DOM Session Transformer" href="writedomsession-transformer.html"/>
@@ -36,6 +35,7 @@
<menu-item label="Parser Transformer" href="parser-transformer.html"/>
<menu-item label="Pattern Transformer" href="pattern-transformer.html"/>
<menu-item label="Session Transformer" href="../../developing/webapps/contexts.html"/>
+ <menu-item label="SQL Transformer" href="sql-transformer.html"/>
</menu>
</book>
1.5 +506 -567 cocoon-2.1/src/documentation/xdocs/userdocs/transformers/sql-transformer.xml
Index: sql-transformer.xml
===================================================================
RCS file: /home/cvs/cocoon-2.1/src/documentation/xdocs/userdocs/transformers/sql-transformer.xml,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- sql-transformer.xml 12 Oct 2003 13:04:49 -0000 1.4
+++ sql-transformer.xml 14 Oct 2003 21:41:58 -0000 1.5
@@ -1,583 +1,522 @@
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.0//EN" "../../dtd/document-v10.dtd">
-
<document>
-<header>
-<title>SQL Transformer</title>
- <version>0.9</version>
-<authors>
- <person name="Sven Beauprez" email="Sven.Beauprez@the-ecorp.com"/>
- <person name="Davanum Srinivas" email="dims@yahoo.com"/>
-</authors>
-</header>
-<body>
-
-
-<s1 title="Introduction">
-<p>
-The purpose of the SQLTransformer is to query a database and translate the
-result to XML. To retrieve the information from the database, you are not
-restricted to use simple SQL statements (eg select, insert, update), it is also
-possible to use stored procedures. In combination with other transformers (eg
-FilterTransformer), this one can be very powerful.
-</p>
- <ul>
- <li>Name : sql</li>
- <li>Class: org.apache.cocoon.transformation.SQLTransformer</li>
- <li>Cacheable: no.</li>
- </ul>
-</s1>
-
-<s1 title="Basic functionality">
-<p>
-To be able to query a database, we need XML that describes exactly what we want
-to do. The general structure of this input XML is as follows:
-</p>
-
- <source>
- <![CDATA[
- <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
- <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
- <query>
- <!-- here comes the SQL statement or stored procedure -->
- </query>
- </execute-query>
- </page>
- ]]>
- </source>
-
-<p>
-Nothing prevents you from putting other XML around the page element. If you do,
-it will stay untouched. The format of the SQL statement or the stored procedure
-is exactly the same as if you would call it directly from java with a prepared
-statement or a callable statement.
-</p>
-<p>
-The query element has the following optional attributes:
-</p>
-<ol>
-<li>
-name:
-Naming a query implicates naming the corresponding rowset (see below).
-When you have a sequence of queries you want to execute, it can be handy give
-them a name. To process the retrieved data of a certain query, you can use
-another transformer to check the name of the rowset and to execute the necessary
-business logic on it.
-<br/>
-usage: <query name="myName">
-</li>
-<li>
-isstoredprocedure:
-When you want to use stored procedures, you have to explicitly add this
-attribute to the query element. By default, the transformer assumes that you
-want to execute a SQL statement.
-<br/>
-usage: <query isstoredprocedure="true">
-
-</li>
-</ol>
-<p>
-Here is an example of how the input XML might look like:
-</p>
- <source>
- <![CDATA[
- <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
-
- <title>Hello</title>
- <content>
- <para>This is my first Cocoon page filled with sql data!</para>
-
- <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
- <query name="department">
- select id,name from department_table
- </query>
- </execute-query>
- </content>
- </page>
- ]]>
- </source>
-
-<p>
-You can use the file generator to retrieve the XML from the filesystem.
-To invoke the SQLTransformer you have to add following to the sitemap:
-</p>
-
- <source>
- <![CDATA[
- <map:transform type="sql">
- <map:parameter name="use-connection" value="personnel"/>
- <map:parameter name="show-nr-of-rows" value="true"/>
- <map:parameter name="clob-encoding" value="UTF-8"/>
- </map:transform>
- ]]>
- </source>
-
-<p>
-The "use-connection" parameter defines which connection, defined under the
-datasources element in cocoon.xconf, the SQLTransformer has to use to retrieve
-the data.
-</p>
-<p>
-The 'show-nr-of-rows' instructs the transformer to count the number of rows in
-the resultset explicitly and to set the result as attribute to the rowset
-element. This attribute is only useful in combination with an sql statement,
-not with stored procedures. If a stored procedure returns a resultset and you
-want to know how many rows it contains, you have to count the number of rows in
-another transformer or your stored procedure has to return it also (last
-solution is the best one)
-</p>
-<p>
-The "clob-encoding" parameter defines what encoding should be used in
-getting content from CLOB columns.
-</p>
-<p>
-The output XML will look as follows:
-</p>
-
- <source>
- <![CDATA[
- <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
- <title>Hello</title>
- <content>
- <para>This is my first Cocoon page filled with sql data!</para>
- <rowset nrofrows="2" name="department"
- xmlns="http://apache.org/cocoon/SQL/2.0">
+ <header>
+ <title>SQL Transformer</title>
+ <version>0.9</version>
+ <authors>
+ <person name="Sven Beauprez" email="Sven.Beauprez@the-ecorp.com"/>
+ <person name="Davanum Srinivas" email="dims@yahoo.com"/>
+ </authors>
+ </header>
+ <body>
+ <s1 title="Introduction">
+ <p>
+ The purpose of the SQLTransformer is to query a database and translate
+ the result to XML. To retrieve the information from the database, you
+ are not restricted to use simple SQL statements (e.g. select, insert,
+ update), it is also possible to use stored procedures. In combination
+ with other transformers (e.g. FilterTransformer), this one can be very
+ powerful.
+ </p>
+ <ul>
+ <li>Name: sql</li>
+ <li>Class: org.apache.cocoon.transformation.SQLTransformer</li>
+ <li>Cacheable: no</li>
+ </ul>
+ </s1>
+ <s1 title="Basic functionality">
+ <p>
+ To be able to query a database, we need XML that describes exactly what
+ we want to do. The general structure of this input XML is as follows:
+ </p>
+ <source>
+ <![CDATA[
+ <page>
+ <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
+ <query>
+ <!-- here comes the SQL statement or stored procedure -->
+ </query>
+ </execute-query>
+ </page>
+ ]]></source>
+ <p>
+ Nothing prevents you from putting other XML around the
+ <code>execute-query</code> element. Any element not in the SQL namespace
+ will stay untouched. The format of the SQL statement or the stored
+ procedure is exactly the same as if you would call it directly from java
+ with a prepared statement or a callable statement.
+ </p>
+ <p>The query element has the following optional attributes:</p>
+ <ol>
+ <li>
+ <strong>name</strong>:
+ Naming a query implicates naming the corresponding rowset (see below).
+ When you have a sequence of queries you want to execute, it can be
+ handy give them a name. To process the retrieved data of a certain
+ query, you can use another transformer to check the name of the rowset
+ and to execute the necessary business logic on it.
+ <br/>
+ usage: <code><query name="myName"></code>
+ </li>
+ <li>
+ <strong>isstoredprocedure</strong>:
+ When you want to use stored procedures, you have to explicitly add
+ this attribute to the query element. By default, the transformer
+ assumes that you want to execute a SQL statement.
+ <br/>
+ usage: <code><query isstoredprocedure="true"></code>
+ </li>
+ </ol>
+ <p>Here is an example of how the input XML might look like:</p>
+ <source>
+ <![CDATA[
+ <page>
+ <title>Hello</title>
+ <content>
+ <para>This is my first Cocoon page filled with sql data!</para>
+ <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
+ <query name="department">
+ select id,name from department_table
+ </query>
+ </execute-query>
+ </content>
+ </page>
+ ]]></source>
+ <p>
+ You can use the file generator to retrieve the XML from the filesystem.
+ To invoke the SQLTransformer you have to add following to the sitemap:
+ </p>
+ <source>
+ <![CDATA[
+ <map:transform type="sql">
+ <map:parameter name="use-connection" value="personnel"/>
+ <map:parameter name="show-nr-of-rows" value="true"/>
+ <map:parameter name="clob-encoding" value="UTF-8"/>
+ </map:transform>
+ ]]></source>
+ <p>
+ The <code>use-connection</code> parameter defines which connection,
+ defined under the datasources element in <code>cocoon.xconf</code>, the
+ SQLTransformer has to use to retrieve the data.
+ </p>
+ <p>
+ The <code>show-nr-of-rows</code> instructs the transformer to count the
+ number of rows in the resultset explicitly and to set the result as
+ attribute to the rowset element. This attribute is only useful in
+ combination with a sql statement, not with stored procedures. If a
+ stored procedure returns a resultset and you want to know how many rows
+ it contains, you have to count the number of rows in another transformer
+ or your stored procedure has to return it also (last solution is the
+ best one).
+ </p>
+ <p>
+ The <code>clob-encoding</code> parameter defines what encoding should be
+ used in getting content from CLOB columns.
+ </p>
+ <p>The output XML will look as follows:</p>
+ <source>
+ <![CDATA[
+ <page>
+ <title>Hello</title>
+ <content>
+ <para>This is my first Cocoon page filled with sql data!</para>
+ <rowset nrofrows="2" name="department"
+ xmlns="http://apache.org/cocoon/SQL/2.0">
+ <row>
+ <id>1</id>
+ <name>Programmers</name>
+ </row>
+ <row>
+ <id>2</id>
+ <name>Loungers</name>
+ </row>
+ </rowset>
+ </content>
+ </page>
+ ]]></source>
+ <p>
+ If you use this in combination with the <code>simple-sql2html.xsl</code>
+ stylesheet,
+ </p>
+ <source>
+ <![CDATA[
+ <map:transform src="stylesheets/simple-sql2html.xsl"/>
+ ]]></source>
+ <p>you will get a more visually attractive page.</p>
+ <p>See below for a more in depth example with stored procedures.</p>
+ <p>
+ By now you should be able to use the SQLTransformer, but there are some
+ more options you might find useful...
+ </p>
+ </s1>
+ <s1 title="Advanced functionality">
+ <s2 title="Substitution">
+ <p>
+ Sometimes you need more information before you can execute a query,
+ e.g. the name of the user that is currently logged on your site. This
+ information is only available at runtime and hence can only be
+ substituted in the query when available.
+ </p>
+ <p>
+ To pass this information to the SQL statement, the input XML has to
+ look like this:
+ </p>
+ <source>
+ <![CDATA[
+ <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
+ <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
+ <query>
+ select id,name from employee_table where name =
+ '<sql:substitute-value sql:name="username"/>'
+ </query>
+ </execute-query>
+ </page>
+ ]]></source>
+ <p>
+ The substitution is done by the SQLTransformer before it executes the
+ query (before it calls the method <code>prepareStatement</code>!). For
+ this, the transformer has to be given the necessary values via the
+ sitemap (as parameter):
+ </p>
+ <source>
+ <![CDATA[
+ <map:transform type="sql">
+ <map:parameter name="use-connection" value="personnel"/>
+ <map:parameter name="show-nr-of-rows" value="true"/>
+ <map:parameter name="username" value="Stefano Mazzocchi"/>
+ </map:transform>
+ ]]></source>
+ <p>
+ Whenever the transformer encounters a <code>substitute-value</code>
+ element for which the attribute <code>name</code> contains the value
+ <code>username</code>, it will replace this element with the value
+ <code>Stefano Mazzocchi</code>.
+ </p>
+ <p>The output XML will be as follow:</p>
+ <source>
+ <![CDATA[
+ <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
+ <rowset nrofrows="1" xmlns="http://apache.org/cocoon/SQL/2.0">
+ <row>
+ <id>2</id>
+ <name>Stefano Mazzocchi</name>
+ </row>
+ </rowset>
+ </page>
+ ]]></source>
+ <p>
+ It is also possible to use substitution in combination with stored
+ procedures.
+ </p>
+ </s2>
+ <s2 title="Ancestors">
+ <p>This functionality is best described by a simple example.</p>
+ <p>Take following input XML:</p>
+ <source>
+ <![CDATA[
+ <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
+ <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
+ <query name="department">
+ select id,name from department_table
+ </query>
+ <execute-query>
+ <query name="employee">
+ select id,name from employee_table where department_id =
+ <ancestor-value sql:name="id" sql:level="1"/>
+ </query>
+ </execute-query>
+ </execute-query>
+ </page>
+ ]]></source>
+ <p>
+ The first query will retrieve all <code>id</code>'s and
+ <code>name</code>'s from the <code>department_table</code> table. For
+ each <code>id</code> that comes from the
+ <code>department_table</code>, the second query, in which the
+ <code>ancestor-value</code> element will be replaced by the
+ <code>id</code>, will be executed. The above example will be
+ transformed to the following XML:
+ </p>
+ <source>
+ <![CDATA[
+ <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
+ <rowset nrofrows="2" name="department"
+ xmlns="http://apache.org/cocoon/SQL/2.0">
+ <row>
+ <id>1</id>
+ <name>Programmers</name>
+ <rowset nrofrows="2" name="employee">
<row>
<id>1</id>
- <name>Programmers</name>
+ <name>Donald Ball</name>
</row>
<row>
<id>2</id>
- <name>Loungers</name>
- </row>
- </rowset>
- </content>
- </page>
- ]]>
- </source>
-
-<p>
-If you use this in combination with the "simple-sql2html" XSL stylesheet,
-</p>
- <source>
- <![CDATA[
- <map:transform src="stylesheets/simple-sql2html.xsl"/>
- ]]>
- </source>
-
-<p>
-you will get a more visually attractive page.
-</p>
-<p>
-See below for a more in depth example with stored procedures.
-</p>
-<p>
-By now you should be able to use the SQLTransformer, but there are some more
-options you might find useful...
-</p>
-
-</s1>
-
-<s1 title="Advanced functionality">
-<s2 title="Substitution">
-<p>
-Sometimes you need more information before you can execute a query, eg. the name
-of the user that is currently logged on your site. This information is only
-available at runtime and hence can only be substituted in the query when
-available.
-</p>
-<p>
-To pass this information to the SQL statement, the input XML has to look like
-this:
-</p>
- <source>
- <![CDATA[
- <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
- <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
- <query>
- select id,name from employee_table where name = '<sql:substitute-value
- sql:name="username"/>'
- </query>
- </execute-query>
- </page>
- ]]>
- </source>
-<p>
-The substitution is done by the SQLTransformer before it executes the query
-(before it calls the method prepareStatement!). For this, the transformer has to
-be given the necessary values via the sitemap (as parameter):
-</p>
- <source>
- <![CDATA[
- <map:transform type="sql">
- <map:parameter name="use-connection" value="personnel"/>
- <map:parameter name="show-nr-of-rows" value="true"/>
- <map:parameter name="username" value="Stefano Mazzocchi"/>
- </map:transform>
- ]]>
- </source>
-<p>
-Whenever the transformer encounters a 'substitute-value' element for which the
-attribute 'name' contains the value 'username', it will replace this element
-with the value 'Stefano Mazzocchi' (without the single quotes!).
-</p>
-<p>
-The output XML will be as follow:
-</p>
- <source>
- <![CDATA[
- <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
- <rowset nrofrows="1" xmlns="http://apache.org/cocoon/SQL/2.0">
- <row>
- <id>2</id>
<name>Stefano Mazzocchi</name>
</row>
</rowset>
- </page>
- ]]>
- </source>
-
-<p>
-It is also possible to use substitution in combination with stored procedures.
-</p>
-</s2>
-
-<s2 title="Ancestors">
-<p>
-This functionality is best described by a simple example.
-</p>
-<p>
-Take following input XML:
-</p>
-
- <source>
- <![CDATA[
- <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
- <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
- <query name="department" >
- select id,name from department_table
- </query>
- <execute-query>
- <query name="employee">
- select id,name from employee_table where department_id =
-<ancestor-value
- sql:name="id" sql:level="1"/>
- </query>
- </execute-query>
- </execute-query>
- </page>
- ]]>
- </source>
-
-<p>
-The first query will retrieve all id's and name's from the department_table
-table. For each id that comes from the department_table, the second query, in
-which the 'ancestor-value' element will be replaced by the id, will be executed.
-The above example will be transformed to the following XML:
-</p>
-
- <source>
- <![CDATA[
- <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
- <rowset nrofrows="2" name="department"
- xmlns="http://apache.org/cocoon/SQL/2.0">
+ </row>
+ <row>
+ <id>2</id>
+ <name>Loungers</name>
+ <rowset nrofrows="1" name="employee">
<row>
- <id>1</id>
- <name>Programmers</name>
- <rowset nrofrows="2" name="employee">
- <row>
- <id>1</id>
- <name>Donald Ball</name>
- </row>
- <row>
- <id>2</id>
- <name>Stefano Mazzocchi</name>
- </row>
- </rowset>
- </row>
- <row>
- <id>2</id>
- <name>Loungers</name>
- <rowset nrofrows="1" name="employee">
- <row>
- <id>3</id>
- <name>Pierpaolo Fumagalli</name>
- </row>
- </rowset>
+ <id>3</id>
+ <name>Pierpaolo Fumagalli</name>
</row>
</rowset>
- </page>
- ]]>
- </source>
-
-</s2>
-
-<s2 title="in- and out-parameters">
-
-<p>
-Stored procedures can return data as a parameter. To make use of this
-functionality in java, you have to register these parameters as 'out
-parameters'. Since this information is application specific, the SQLTransformer
-uses reflection to retrieve the data in the right format. For this, an extra
-element is needed in the input XML:
-</p>
-
- <source>
- <![CDATA[
- <out-parameter sql:nr="1" sql:name="code"
-sql:type="java.sql.Types.INTEGER"/>
- ]]>
- </source>
-
-<p>
-where:
-</p>
-<ol>
-<li>
-nr:
-The targeted parameter number that will return data of a certain type.
-</li>
-<li>
-type:
-The type of data that will be returned (defined in java.sql.Types or in database
-specific drivers, eg oracle.jdbc.driver.OracleTypes). Once the stored procedure
-returns data in the parameters, the stored procedure tries to process them. If
-the returned parameter is an instance of ResultSet, it will be translated to XML
-as we saw before. In all the other situations, the SQLTransformer will convert
-the parameter to a string.
-</li>
-</ol>
-<p>
-This is an example of how to call an oracle stored procedure and process it with
-the SQLTransformer:
-</p>
-
- <source>
- <![CDATA[
- <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
- <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
- <query isstoredprocedure="true" name="namesearch">
- begin QUICK_SEARCH.FIND_NAME('<sql:substitute-value
- sql:name="username"/>',?,?,?); end;
- </query>
- <out-parameter sql:nr="1" sql:name="code"
- sql:type="java.sql.Types.INTEGER"/>
- <out-parameter sql:nr="2" sql:name="nrofrows"
- sql:type="java.sql.Types.INTEGER"/>
- <out-parameter sql:nr="3" sql:name="resultset"
- sql:type="oracle.jdbc.driver.OracleTypes.CURSOR"/>
- </execute-query>
- </page>
- ]]>
- </source>
-
-<p>
-The SQLTransformer will create 3 elements, respectively 'code', 'nrofrows' and
-'resultset' under the element 'namesearch'. Since the type
-oracle.jdbc.driver.OracleTypes.CURSOR' corresponds to a ResultSet, a 'rowset'
-element will be created, containing all the data of the resultset.
-It is also possible to use an 'in-parameter' element, eg. <in-parameter
-sql:nr="1" sql:value="1"/>.
-This functionality is only provided to be complete, because it is available in
-java itself. You can also use the 'in-parameter' in combination with a SQL
-statement.
-Used in combination with an out-parameter, a ?-parameter can be an in-parameter
-and an out-parameter at the same time.
-</p>
-
-</s2>
-</s1>
-<s1 title="Combined with other transformers">
-<s2 title="Filtertransformer">
-<p>
-When you query a database and it returns too many rows too process at once, you
-might want to take a block of elements, process this block and ignore the rest
-for now. You can best compare it to a search on Google: they only return 10
-results in one time, for more results you have to click on another block (page).
-It wouldn't be wise to process more than 10 elements in the pipeline if you only
-need to display 10 elements.
-</p>
-<p>
-Assume that a query returns 56 row elements (by using the SQLTransformer) and
-that you only want to display the first 10 elements:
-</p>
-<p>
-Output XML from the SQLTransformer:
-</p>
-
- <source>
- <![CDATA[
- <rowset nrofrows="56" name="test"
-xmlns="http://apache.org/cocoon/SQL/2.0">
- <row>
- <!-- db record -->
- </row>
- <row>
- <!-- db record -->
- </row>
- <row>
- <!-- db record -->
- </row>
-
- ...
-
- <row>
- <!-- db record -->
- </row>
- </rowset>
- ]]>
- </source>
-
-<p>
-By adding following lines to the sitemap, just under the SQLTransformer, you
-restrict the results to 10 elements in the first block:
-</p>
-
- <source>
- <![CDATA[
- <map:transform type="filter">
- <map:parameter name="element-name" value="row"/>
- <map:parameter name="count" value="10"/>
- <map:parameter name="blocknr" value="1"/>
- </map:transform>
- ]]>
- </source>
-
-<p>
-output XML:
-</p>
-
- <source>
- <![CDATA[
- <rowset nrofrows="56" name="test"
-xmlns="http://apache.org/cocoon/SQL/2.0">
- <block id="1">
- <row>
- <!-- db record -->
- </row>
-
- <!-- total of 10 rows -->
-
- <row>
- <!-- db record -->
- </row>
- </block>
- <block id="2"/>
- <block id="3"/>
- <block id="4"/>
- <block id="5"/>
- <block id="6"/>
- </rowset>
- ]]>
- </source>
-
-<p>
-To make it more dynamically, put something like {reqCount} and {reqBlock} in the
-values for count and blocknr respectively. These can be parameters from the
-request and they can be passed to the sitemap with an action.
-</p>
-<p>
-The FilterTransformer is a standalone component, you don't need to use it in
-combination with the SQLTransformer.
-</p>
-
-</s2>
-<s2 title="WriteDOMSessionTransformer">
-
-<p>
-If you only use the FilterTransformer in combination with the SQLTransformer,
-you have to query the database each time the user wants to see another part of
-the result. You can better store the result in the session after the first
-request and retrieve the result from the session for the subsequent requests.
-This can be done by using a selector, which checks if the data is available in
-the session or not.
-</p>
-<p>
-WriteDOMSessionTransformer can build a DOM starting from a given element (which
-will be the root of the DOM tree) and store it in the session. If you want to
-store the result of a query, you have to add following to the sitemap:
-</p>
- <source>
- <![CDATA[
- <map:transform type="writeDOMsession">
- <map:parameter name="dom-name" value="DBresult"/>
- <map:parameter name="dom-root-element" value="rowset"/>
- </map:transform>
- ]]>
- </source>
-<p>
-The transformer will build a DOM tree with rowset as root element and will store
-it in the session with the name "DBresult".
-</p>
-<p>
-Note: most of the times, it is not smart to keep the output XML of the
-SQLTransformer in the session. Check if it is better to do the necessary
-transformations first, so that you get a smaller DOM, and then put the result in
-the session. You probably will be able to use the FilterTransformer on the
-transformed XML also.
-</p>
-<p>
-The WriteDOMSessionTransformer is a standalone component, you don't need to use
-it in combination with the SQLTransformer.
-</p>
-</s2>
-
-<s2 title="ReadDOMSessionTransformer">
-
-<p>
-Simply transforms a DOM to SAX-events, which can be used further on in the
-pipeline. Once you stored the result of a query in the session with the
-WriteDOMSessionTransformer, you can read it again with the
-ReadDOMSessionTransformer:
-</p>
-
- <source>
- <![CDATA[
- <map:transform type="readDOMsession">
- <map:parameter name="dom-name" value="DBresult"/>
- <map:parameter name="trigger-element" value="users"/>
- <map:parameter name="position" value="after"/>
- </map:transform>
- ]]>
- </source>
-
-<p>
-In this example, the SAX-events that came from the DOM tree that is stored in
-the session with name DBresult will be added after the users element. This means
-as soon that the transformer encounters the end-element 'users', it will start
-to generate SAX-events from the DOM tree. There are three possible positions,
-'before','in' and 'after':
-</p>
-<ol>
-<li>'before' means that when the transformer encounters the 'users' element, it
-will FIRST translate the DOM tree to SAX-events and THEN it will continue to
-forward the other SAX-events (starting with 'users').
-</li>
-<li>'in' means that the transformer will forward the startElement event for
-'users' and that it IMMEDIATELY starts to generate SAX-events from the DOM-tree.
-After that, it will continue to forward the child elements of users and then all
-the other elements.
-</li>
-<li>'after' means that the transformer starts to generate SAX-events from the
-DOM-tree just after it has forwarded the end-element 'users'.
-</li>
-</ol>
-<p>
-The ReadDOMSessionTransformer is a standalone component, you don't need to use
-it in combination with the WriteDOMSessionTransformer.
-</p>
-</s2>
-
-<p>
-That's it,
-</p>
-<p>
-Sven Beauprez
-</p>
-
-
-</s1>
-
-</body>
+ </row>
+ </rowset>
+ </page>
+ ]]></source>
+ </s2>
+ <s2 title="in- and out-parameters">
+ <p>
+ Stored procedures can return data as a parameter. To make use of this
+ functionality in java, you have to register these parameters as
+ <em>out parameters</em>. Since this information is application
+ specific, the SQLTransformer uses reflection to retrieve the data in
+ the right format. For this, an extra element is needed in the input
+ XML:
+ </p>
+ <source>
+ <![CDATA[
+ <out-parameter sql:nr="1" sql:name="code"
+ sql:type="java.sql.Types.INTEGER"/>
+ ]]></source>
+ <p>where:</p>
+ <ol>
+ <li>
+ <strong>nr</strong>:
+ The targeted parameter number that will return data of a certain
+ type.
+ </li>
+ <li>
+ <strong>type</strong>:
+ The type of data that will be returned (defined in
+ <code>java.sql.Types</code> or in database specific drivers, e.g.
+ <code>oracle.jdbc.driver.OracleTypes</code>). Once the stored
+ procedure returns data in the parameters, the stored procedure tries
+ to process them. If the returned parameter is an instance of
+ <code>ResultSet</code>, it will be translated to XML as we saw
+ before. In all the other situations the SQLTransformer will convert
+ the parameter to a string.
+ </li>
+ </ol>
+ <p>
+ This is an example of how to call an oracle stored procedure and
+ process it with the SQLTransformer:
+ </p>
+ <source>
+ <![CDATA[
+ <page xmlns:sql="http://apache.org/cocoon/SQL/2.0">
+ <execute-query xmlns="http://apache.org/cocoon/SQL/2.0">
+ <query isstoredprocedure="true" name="namesearch">
+ begin QUICK_SEARCH.FIND_NAME('<sql:substitute-value
+ sql:name="username"/>',?,?,?); end;
+ </query>
+ <out-parameter sql:nr="1" sql:name="code"
+ sql:type="java.sql.Types.INTEGER"/>
+ <out-parameter sql:nr="2" sql:name="nrofrows"
+ sql:type="java.sql.Types.INTEGER"/>
+ <out-parameter sql:nr="3" sql:name="resultset"
+ sql:type="oracle.jdbc.driver.OracleTypes.CURSOR"/>
+ </execute-query>
+ </page>
+ ]]></source>
+ <p>
+ The SQLTransformer will create 3 elements, respectively
+ <code>code</code>, <code>nrofrows</code> and <code>resultset</code>
+ under the element <code>namesearch</code>. Since the type
+ <code>oracle.jdbc.driver.OracleTypes.CURSOR</code> corresponds to a
+ <code>ResultSet</code>, a <code>rowset</code> element will be created,
+ containing all the data of the resultset. It is also possible to use
+ an <em>in-parameter</em> element, e.g.
+ <code><in-parameter sql:nr="1" sql:value="1"/></code>. This
+ functionality is only provided to be complete, because it is available
+ in Java itself. You can also use the <em>in-parameter</em> in
+ combination with a SQL statement. Used in combination with an
+ <em>out-parameter</em>, a <em>?-parameter</em> can be an
+ <em>in-parameter</em> and an <em>out-parameter</em> at the same time.
+ </p>
+ </s2>
+ </s1>
+ <s1 title="Combined with other transformers">
+ <s2 title="Filtertransformer">
+ <p>
+ When you query a database and it returns too many rows to process at
+ once, you might want to take a block of elements, process this block
+ and ignore the rest for now. You can best compare it to a search on
+ Google: they only return 10 results in one time, for more results you
+ have to click on another block (page). It wouldn't be wise to process
+ more than 10 elements in the pipeline if you only need to display 10
+ elements.
+ </p>
+ <p>
+ Assume that a query returns 56 row elements (by using the
+ SQLTransformer) and that you only want to display the first 10
+ elements:
+ </p>
+ <p>Output XML from the SQLTransformer:</p>
+ <source>
+ <![CDATA[
+ <rowset nrofrows="56" name="test"
+ xmlns="http://apache.org/cocoon/SQL/2.0">
+ <row>
+ <!-- db record -->
+ </row>
+ <row>
+ <!-- db record -->
+ </row>
+
+ ...
+
+ <row>
+ <!-- db record -->
+ </row>
+ </rowset>
+ ]]></source>
+ <p>
+ By adding following lines to the sitemap, just under the
+ SQLTransformer, you restrict the results to 10 elements in the first
+ block:
+ </p>
+ <source>
+ <![CDATA[
+ <map:transform type="filter">
+ <map:parameter name="element-name" value="row"/>
+ <map:parameter name="count" value="10"/>
+ <map:parameter name="blocknr" value="1"/>
+ </map:transform>
+ ]]></source>
+ <p>output XML:</p>
+ <source>
+ <![CDATA[
+ <rowset nrofrows="56" name="test"
+ xmlns="http://apache.org/cocoon/SQL/2.0">
+ <block id="1">
+ <row>
+ <!-- db record -->
+ </row>
+
+ <!-- total of 10 rows -->
+
+ <row>
+ <!-- db record -->
+ </row>
+ </block>
+ <block id="2"/>
+ <block id="3"/>
+ <block id="4"/>
+ <block id="5"/>
+ <block id="6"/>
+ </rowset>
+ ]]></source>
+ <p>
+ To make it more dynamically, put something like
+ <code>{reqCount}</code> and <code>{reqBlock}</code> in the values for
+ <em>count</em> and <em>blocknr</em> respectively. These can be
+ parameters from the request and they can be passed to the sitemap with
+ an action.
+ </p>
+ <p>
+ The FilterTransformer is a standalone component; you don't need to use
+ it in combination with the SQLTransformer.
+ </p>
+ </s2>
+ <s2 title="WriteDOMSessionTransformer">
+ <p>
+ If you only use the FilterTransformer in combination with the
+ SQLTransformer, you have to query the database each time the user
+ wants to see another part of the result. You can better store the
+ result in the session after the first request and retrieve the result
+ from the session for the subsequent requests. This can be done by
+ using a selector, which checks if the data is available in the session
+ or not.
+ </p>
+ <p>
+ WriteDOMSessionTransformer can build a DOM starting from a given
+ element (which will be the root of the DOM tree) and store it in the
+ session. If you want to store the result of a query, you have to add
+ following to the sitemap:
+ </p>
+ <source>
+ <![CDATA[
+ <map:transform type="writeDOMsession">
+ <map:parameter name="dom-name" value="DBresult"/>
+ <map:parameter name="dom-root-element" value="rowset"/>
+ </map:transform>
+ ]]></source>
+ <p>
+ The transformer will build a DOM tree with <code>rowset</code> as root
+ element and will store it in the session with the name
+ <code>DBresult</code>.
+ </p>
+ <note>
+ Most of the times, it is not smart to keep the output XML of the
+ SQLTransformer in the session. Check if it is better to do the
+ necessary transformations first, so that you get a smaller DOM, and
+ then put the result in the session. You probably will be able to use
+ the FilterTransformer on the transformed XML also.
+ </note>
+ <p>
+ The WriteDOMSessionTransformer is a standalone component, you don't
+ need to use it in combination with the SQLTransformer.
+ </p>
+ </s2>
+ <s2 title="ReadDOMSessionTransformer">
+ <p>
+ Simply transforms a DOM to SAX events, which can be used further on in
+ the pipeline. Once you stored the result of a query in the session
+ with the WriteDOMSessionTransformer, you can read it again with the
+ ReadDOMSessionTransformer:
+ </p>
+ <source>
+ <![CDATA[
+ <map:transform type="readDOMsession">
+ <map:parameter name="dom-name" value="DBresult"/>
+ <map:parameter name="trigger-element" value="users"/>
+ <map:parameter name="position" value="after"/>
+ </map:transform>
+ ]]></source>
+ <p>
+ In this example the SAX events, that come from the DOM tree stored in
+ the session with name <code>DBresult</code>, will be added after the
+ <code>users</code> element. This means as soon that the transformer
+ encounters the end element <code>users</code>, it will start to
+ generate SAX events from the DOM tree. There are three possible
+ positions, <code>before</code>, <code>in</code> and
+ <code>after</code>:
+ </p>
+ <ol>
+ <li>
+ <strong><code>before</code></strong> means that when the transformer
+ encounters the <code>users</code> element, it will FIRST translate
+ the DOM tree to SAX events and THEN it will continue to forward the
+ other SAX events (starting with <code>users</code>).
+ </li>
+ <li>
+ <strong><code>in</code></strong> means that the transformer will
+ forward the start element event for <code>users</code> and that it
+ IMMEDIATELY starts to generate SAX events from the DOM tree. After
+ that, it will continue to forward the child elements of users and
+ then all the other elements.
+ </li>
+ <li>
+ <strong><code>after</code></strong> means that the transformer
+ starts to generate SAX events from the DOM tree just after it has
+ forwarded the end element <code>users</code>.
+ </li>
+ </ol>
+ <p>
+ The ReadDOMSessionTransformer is a standalone component, you don't
+ need to use it in combination with the WriteDOMSessionTransformer.
+ </p>
+ </s2>
+ <p>That's it,</p>
+ <p>Sven Beauprez</p>
+ </s1>
+ </body>
</document>