diff options
Diffstat (limited to 'engine')
| -rw-r--r-- | engine/lib/query.php | 71 |
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 { |