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authoricewing <icewing@36083f99-b078-4883-b0ff-0f9b5a30f544>2008-06-04 14:56:33 +0000
committericewing <icewing@36083f99-b078-4883-b0ff-0f9b5a30f544>2008-06-04 14:56:33 +0000
commit8f85395784c896896e68d41b74222d7b4c806ab3 (patch)
treec97c70025309fd3f117bedcef146ced7a86624c1 /engine/lib
parent8fd7f6e98053c443b9dd86df84e19ff555833ffd (diff)
downloadelgg-8f85395784c896896e68d41b74222d7b4c806ab3.tar.gz
elgg-8f85395784c896896e68d41b74222d7b4c806ab3.tar.bz2
Marcus Povey <marcus@dushka.co.uk>
* Documentation added to query. git-svn-id: https://code.elgg.org/elgg/trunk@797 36083f99-b078-4883-b0ff-0f9b5a30f544
Diffstat (limited to 'engine/lib')
-rw-r--r--engine/lib/query.php71
1 files changed, 67 insertions, 4 deletions
diff --git a/engine/lib/query.php b/engine/lib/query.php
index 8abd69a8b..3507bbe2e 100644
--- a/engine/lib/query.php
+++ b/engine/lib/query.php
@@ -448,8 +448,64 @@
}
/**
- * @class Query
- * This class provides a framework to construct complex queries in a safer environment.
+ * @class Query Provides a framework to construct complex queries in a safer environment.
+ *
+ * The usage of this class depends on the type of query you are executing, but the basic idea is to
+ * construct a query out of pluggable classes.
+ *
+ * Once constructed SQL can be generated using the toString method, this should happen automatically
+ * if you pass the Query object to get_data or similar.
+ *
+ * To construct a query, create a new Query() object and begin populating it with the various classes
+ * that define the various aspects of the query.
+ *
+ * Notes:
+ * - You do not have to specify things in any particular order, provided you specify all required
+ * components.
+ * - With database tables you do not have to specify your db prefix, this will be added automatically.
+ * - When constructing your query keep an eye on the error log - any problems will get spit out here.
+ * Note also that __toString won't let you throw Exceptions (!!!) so these are caught and echoed to
+ * the log instead.
+ *
+ * Here is an example of a select query which requests some data out of the entities table with an
+ * order and limit that uses a subset where and some normal where queries:
+ *
+ * <blockquote>
+ * // Construct the query
+ * $query = new Query();
+ *
+ * // Say which table we're interested in
+ * $query->addTable(new TableQueryComponent("entities"));
+ *
+ * // What fields are we interested in
+ * $query->addSelectField(new SelectFieldQueryComponent("entities","*"));
+ *
+ * // Add access control (Default access control uses default fields on entities table.
+ * // Note that it will error without something specified here!
+ * $query->setAccessControl(new AccessControlQueryComponent());
+ *
+ * // Set a limit and offset, may be omitted.
+ * $query->setLimitAndOffset(new LimitOffsetQueryComponent(10,0));
+ *
+ * // Specify the order, may be omitted
+ * $query->setOrder(new OrderQueryComponent("entities", "subtype", "desc"));
+ *
+ * // Construct a where query
+ * //
+ * // This demonstrates a WhereSet which lets you have sub wheres, a
+ * // WhereStatic which lets you compare a table field against a value and a
+ * // Where which lets you compare a table/field with another table/field.
+ * $query->addWhere(
+ * new WhereSetQueryComponent(
+ * array(
+ * new WhereStaticQueryComponent("entities", "subtype","=", 1),
+ * new WhereQueryComponent("entities","subtype","=", "entities", "subtype")
+ * )
+ * )
+ * );
+ *
+ * get_data($query);
+ * </blockquote>
*
* @author Marcus Povey
*/
@@ -677,9 +733,16 @@
}
/**
- * @class SimpleQuery
- * A wrapper for Query which provides simple interface for common functions.
+ * @class SimpleQuery A wrapper for Query which provides simple interface for common functions.
+ *
+ * This class provides simple interface functions for constructing a (reasonably) standard database
+ * query.
+ *
+ * The constructor for this class sets a number of defaults, for example sets default access controls
+ * and a limit and offset - to change this then set it manually.
+ *
* @author Marcus Povey
+ * @see Query
*/
class SimpleQuery extends Query
{