Merge pull request #3373 from jim-parry/userguide/querybuilder
User Guide update - Query Builder (fixes #2512)
diff --git a/user_guide_src/source/database/configuration.rst b/user_guide_src/source/database/configuration.rst
index 34cefff..9f52ad2 100644
--- a/user_guide_src/source/database/configuration.rst
+++ b/user_guide_src/source/database/configuration.rst
@@ -141,7 +141,8 @@
The :doc:`Query Builder Class <query_builder>` is globally enabled or
disabled by setting the $query_builder variable in the database
-configuration file to TRUE/FALSE (boolean). If you are not using the
+configuration file to TRUE/FALSE (boolean). The default setting is TRUE.
+If you are not using the
query builder class, setting it to FALSE will utilize fewer resources
when the database classes are initialized.
diff --git a/user_guide_src/source/database/query_builder.rst b/user_guide_src/source/database/query_builder.rst
index 5bfdfdb..3203ff1 100644
--- a/user_guide_src/source/database/query_builder.rst
+++ b/user_guide_src/source/database/query_builder.rst
@@ -19,7 +19,9 @@
class in your database config file, allowing the core database library
and adapter to utilize fewer resources.
-.. contents:: Page Contents
+.. contents::
+ :local:
+ :depth: 1
**************
Selecting Data
@@ -28,7 +30,7 @@
The following functions allow you to build SQL **SELECT** statements.
$this->db->get()
-================
+----------------
Runs the selection query and returns the result. Can be used by itself
to retrieve all records from a table::
@@ -39,7 +41,8 @@
clause::
$query = $this->db->get('mytable', 10, 20);
- // Produces: SELECT * FROM mytable LIMIT 20, 10 (in MySQL. Other databases have slightly different syntax)
+ // Produces: SELECT * FROM mytable LIMIT 20, 10
+ // (in MySQL. Other databases have slightly different syntax)
You'll notice that the above function is assigned to a variable named
$query, which can be used to show the results::
@@ -54,10 +57,13 @@
Please visit the :doc:`result functions <results>` page for a full
discussion regarding result generation.
-$this->db->get_compiled_select()
-================================
+:returns: DB_Result for a successful "read",
+ TRUE for a successful "write", FALSE if an error
-Compiles the selection query just like `$this->db->get()`_ but does not *run*
+$this->db->get_compiled_select()
+--------------------------------
+
+Compiles the selection query just like **$this->db->get()** but does not *run*
the query. This method simply returns the SQL query as a string.
Example::
@@ -79,14 +85,15 @@
// Produces string: SELECT title, content, date FROM mytable LIMIT 20, 10
The key thing to notice in the above example is that the second query did not
-utilize `$this->db->from()`_ and did not pass a table name into the first
+utilize **$this->db->from()** and did not pass a table name into the first
parameter. The reason for this outcome is because the query has not been
-executed using `$this->db->get()`_ which resets values or reset directly
-using `$this->db->reset_query()`_.
+executed using **$this->db->get()** which resets values or reset directly
+using **$this->db->reset_query()**.
+:returns: The SQL select string
$this->db->get_where()
-======================
+----------------------
Identical to the above function except that it permits you to add a
"where" clause in the second parameter, instead of using the db->where()
@@ -98,8 +105,11 @@
.. note:: get_where() was formerly known as getwhere(), which has been removed
+:returns: DB_Result for a successful "read",
+ TRUE for a successful "write", FALSE if an error
+
$this->db->select()
-===================
+-------------------
Permits you to write the SELECT portion of your query::
@@ -119,9 +129,10 @@
$this->db->select('(SELECT SUM(payments.amount) FROM payments WHERE payments.invoice_id=4') AS amount_paid', FALSE);
$query = $this->db->get('mytable');
+:returns: The query builder object
$this->db->select_max()
-=======================
+-----------------------
Writes a "SELECT MAX(field)" portion for your query. You can optionally
include a second parameter to rename the resulting field.
@@ -135,8 +146,7 @@
$query = $this->db->get('members'); // Produces: SELECT MAX(age) as member_age FROM members
-$this->db->select_min()
-=======================
+**$this->db->select_min()**
Writes a "SELECT MIN(field)" portion for your query. As with
select_max(), You can optionally include a second parameter to rename
@@ -148,8 +158,7 @@
$query = $this->db->get('members'); // Produces: SELECT MIN(age) as age FROM members
-$this->db->select_avg()
-=======================
+**$this->db->select_avg()**
Writes a "SELECT AVG(field)" portion for your query. As with
select_max(), You can optionally include a second parameter to rename
@@ -161,8 +170,7 @@
$query = $this->db->get('members'); // Produces: SELECT AVG(age) as age FROM members
-$this->db->select_sum()
-=======================
+**$this->db->select_sum()**
Writes a "SELECT SUM(field)" portion for your query. As with
select_max(), You can optionally include a second parameter to rename
@@ -173,9 +181,11 @@
$this->db->select_sum('age');
$query = $this->db->get('members'); // Produces: SELECT SUM(age) as age FROM members
+:returns: The query builder object
+
$this->db->from()
-=================
+-----------------
Permits you to write the FROM portion of your query::
@@ -186,8 +196,10 @@
.. note:: As shown earlier, the FROM portion of your query can be specified
in the $this->db->get() function, so use whichever method you prefer.
+:returns: The query builder object
+
$this->db->join()
-=================
+-----------------
Permits you to write the JOIN portion of your query::
@@ -211,8 +223,14 @@
$this->db->join('comments', 'comments.id = blogs.id', 'left');
// Produces: LEFT JOIN comments ON comments.id = blogs.id
+:returns: The query builder object
+
+*************************
+Looking for Specific Data
+*************************
+
$this->db->where()
-==================
+------------------
This function enables you to set **WHERE** clauses using one of four
methods:
@@ -277,9 +295,7 @@
$this->db->where('MATCH (field) AGAINST ("value")', NULL, FALSE);
-
-$this->db->or_where()
-=====================
+**$this->db->or_where()**
This function is identical to the one above, except that multiple
instances are joined by OR::
@@ -290,8 +306,10 @@
.. note:: or_where() was formerly known as orwhere(), which has been
removed.
+:returns: The query builder object
+
$this->db->where_in()
-=====================
+---------------------
Generates a WHERE field IN ('item', 'item') SQL query joined with AND if
appropriate
@@ -303,8 +321,7 @@
// Produces: WHERE username IN ('Frank', 'Todd', 'James')
-$this->db->or_where_in()
-========================
+**$this->db->or_where_in()**
Generates a WHERE field IN ('item', 'item') SQL query joined with OR if
appropriate
@@ -315,9 +332,10 @@
$this->db->or_where_in('username', $names);
// Produces: OR username IN ('Frank', 'Todd', 'James')
+:returns: The query builder object
$this->db->where_not_in()
-=========================
+-------------------------
Generates a WHERE field NOT IN ('item', 'item') SQL query joined with
AND if appropriate
@@ -329,8 +347,7 @@
// Produces: WHERE username NOT IN ('Frank', 'Todd', 'James')
-$this->db->or_where_not_in()
-============================
+**$this->db->or_where_not_in()**
Generates a WHERE field NOT IN ('item', 'item') SQL query joined with OR
if appropriate
@@ -341,9 +358,15 @@
$this->db->or_where_not_in('username', $names);
// Produces: OR username NOT IN ('Frank', 'Todd', 'James')
+:returns: The query builder object
+
+
+************************
+Looking for Similar Data
+************************
$this->db->like()
-=================
+-----------------
This method enables you to generate **LIKE** clauses, useful for doing
searches.
@@ -383,8 +406,7 @@
// WHERE `title` LIKE '%match%' ESCAPE '!' AND `page1` LIKE '%match%' ESCAPE '!' AND `page2` LIKE '%match%' ESCAPE '!'
-$this->db->or_like()
-====================
+**$this->db->or_like()**
This method is identical to the one above, except that multiple
instances are joined by OR::
@@ -394,16 +416,14 @@
.. note:: ``or_like()`` was formerly known as ``orlike()``, which has been removed.
-$this->db->not_like()
-=====================
+**$this->db->not_like()**
This method is identical to ``like()``, except that it generates
NOT LIKE statements::
$this->db->not_like('title', 'match'); // WHERE `title` NOT LIKE '%match% ESCAPE '!'
-$this->db->or_not_like()
-========================
+**$this->db->or_not_like()**
This method is identical to ``not_like()``, except that multiple
instances are joined by OR::
@@ -412,8 +432,10 @@
$this->db->or_not_like('body', 'match');
// WHERE `title` LIKE '%match% OR `body` NOT LIKE '%match%' ESCAPE '!'
+:returns: The query builder object
+
$this->db->group_by()
-=====================
+---------------------
Permits you to write the GROUP BY portion of your query::
@@ -426,8 +448,10 @@
.. note:: group_by() was formerly known as groupby(), which has been
removed.
+:returns: The query builder object
+
$this->db->distinct()
-=====================
+---------------------
Adds the "DISTINCT" keyword to a query
@@ -436,9 +460,10 @@
$this->db->distinct();
$this->db->get('table'); // Produces: SELECT DISTINCT * FROM table
+:returns: The query builder object
$this->db->having()
-===================
+-------------------
Permits you to write the HAVING portion of your query. There are 2
possible syntaxes, 1 argument or 2::
@@ -462,13 +487,18 @@
$this->db->having('user_id', 45, FALSE); // Produces: HAVING user_id = 45
-$this->db->or_having()
-======================
+**$this->db->or_having()**
Identical to having(), only separates multiple clauses with "OR".
+:returns: The query builder object
+
+****************
+Ordering results
+****************
+
$this->db->order_by()
-=====================
+---------------------
Lets you set an ORDER BY clause.
@@ -512,8 +542,14 @@
.. note:: Random ordering is not currently supported in Oracle and
will default to ASC instead.
+:returns: The query builder object
+
+****************************
+Limiting or Counting Results
+****************************
+
$this->db->limit()
-==================
+------------------
Lets you limit the number of rows you would like returned by the query::
@@ -525,8 +561,10 @@
$this->db->limit(10, 20); // Produces: LIMIT 20, 10 (in MySQL. Other databases have slightly different syntax)
+:returns: The query builder object
+
$this->db->count_all_results()
-==============================
+------------------------------
Permits you to determine the number of rows in a particular Active
Record query. Queries will accept Query Builder restrictors such as
@@ -537,14 +575,18 @@
$this->db->from('my_table');
echo $this->db->count_all_results(); // Produces an integer, like 17
+:returns: Count of all the records returned by a query
+
$this->db->count_all()
-======================
+----------------------
Permits you to determine the number of rows in a particular table.
Submit the table name in the first parameter. Example::
echo $this->db->count_all('my_table'); // Produces an integer, like 25
+:returns: Count of all the records in the specified table
+
**************
Query grouping
**************
@@ -568,37 +610,34 @@
.. note:: groups need to be balanced, make sure every group_start() is matched by a group_end().
-$this->db->group_start()
-========================
+**$this->db->group_start()**
Starts a new group by adding an opening parenthesis to the WHERE clause of the query.
-$this->db->or_group_start()
-===========================
+**$this->db->or_group_start()**
Starts a new group by adding an opening parenthesis to the WHERE clause of the query, prefixing it with 'OR'.
-$this->db->not_group_start()
-============================
+**$this->db->not_group_start()**
Starts a new group by adding an opening parenthesis to the WHERE clause of the query, prefixing it with 'NOT'.
-$this->db->or_not_group_start()
-===============================
+**$this->db->or_not_group_start()**
Starts a new group by adding an opening parenthesis to the WHERE clause of the query, prefixing it with 'OR NOT'.
-$this->db->group_end()
-======================
+**$this->db->group_end()**
Ends the current group by adding an closing parenthesis to the WHERE clause of the query.
+:returns: The query builder object
+
**************
Inserting Data
**************
$this->db->insert()
-===================
+-------------------
Generates an insert string based on the data you supply, and runs the
query. You can either pass an **array** or an **object** to the
@@ -635,8 +674,11 @@
.. note:: All values are escaped automatically producing safer queries.
+:returns: DB_Query on success, FALSE on failure
+
$this->db->get_compiled_insert()
-================================
+--------------------------------
+
Compiles the insertion query just like `$this->db->insert()`_ but does not
*run* the query. This method simply returns the SQL query as a string.
@@ -672,8 +714,10 @@
.. note:: This method doesn't work for batched inserts.
+:returns: The SQL insert string
+
$this->db->insert_batch()
-=========================
+-------------------------
Generates an insert string based on the data you supply, and runs the
query. You can either pass an **array** or an **object** to the
@@ -700,8 +744,14 @@
.. note:: All values are escaped automatically producing safer queries.
+:returns: Count of the number of records inserted on success, FALSE on failure
+
+*************
+Updating Data
+*************
+
$this->db->replace()
-====================
+--------------------
This method executes a REPLACE statement, which is basically the SQL
standard for (optional) DELETE + INSERT, using *PRIMARY* and *UNIQUE*
@@ -729,8 +779,10 @@
Usage of the ``set()`` method is also allowed and all fields are
automatically escaped, just like with ``insert()``.
+:returns: DB_query object on success, FALSE on failure
+
$this->db->set()
-================
+----------------
This function enables you to set values for inserts or updates.
@@ -788,12 +840,10 @@
$this->db->set($object);
$this->db->insert('mytable');
-*************
-Updating Data
-*************
+:returns: The query builder object
$this->db->update()
-===================
+-------------------
Generates an update string and runs the query based on the data you
supply. You can pass an **array** or an **object** to the function. Here
@@ -839,9 +889,10 @@
You may also use the $this->db->set() function described above when
performing updates.
+:returns: DB_query object on success, FALSE on failure
$this->db->update_batch()
-=========================
+-------------------------
Generates an update string based on the data you supply, and runs the query.
You can either pass an **array** or an **object** to the function.
@@ -882,8 +933,10 @@
due to the very nature of how it works. Instead, ``update_batch()``
returns the number of rows affected.
+:returns: Count of the number of records affected on success, FALSE on failure
+
$this->db->get_compiled_update()
-================================
+--------------------------------
This works exactly the same way as ``$this->db->get_compiled_insert()`` except
that it produces an UPDATE SQL string instead of an INSERT SQL string.
@@ -892,12 +945,14 @@
.. note:: This method doesn't work for batched updates.
+:returns: The SQL update string
+
*************
Deleting Data
*************
$this->db->delete()
-===================
+-------------------
Generates a delete SQL string and runs the query.
@@ -930,17 +985,21 @@
If you want to delete all data from a table, you can use the truncate()
function, or empty_table().
+:returns: DB_Query on success, FALSE on failure
+
$this->db->empty_table()
-========================
+------------------------
Generates a delete SQL string and runs the
query.::
$this->db->empty_table('mytable'); // Produces: DELETE FROM mytable
+:returns: DB_Query on success, FALSE on failure
+
$this->db->truncate()
-=====================
+---------------------
Generates a truncate SQL string and runs the query.
@@ -959,13 +1018,20 @@
.. note:: If the TRUNCATE command isn't available, truncate() will
execute as "DELETE FROM table".
+:returns: DB_Query on success, FALSE on failure
+
$this->db->get_compiled_delete()
-================================
+--------------------------------
+
This works exactly the same way as ``$this->db->get_compiled_insert()`` except
that it produces a DELETE SQL string instead of an INSERT SQL string.
For more information view documentation for `$this->db->get_compiled_insert()`_.
+:returns: The SQL delete string
+
+
+
***************
Method Chaining
***************
@@ -994,23 +1060,25 @@
then 2 uncached select() calls, this will result in 4 select() calls.
There are three Caching functions available:
-$this->db->start_cache()
-========================
+**$this->db->start_cache()**
This function must be called to begin caching. All Query Builder queries
of the correct type (see below for supported queries) are stored for
later use.
-$this->db->stop_cache()
-=======================
+**$this->db->stop_cache()**
This function can be called to stop caching.
-$this->db->flush_cache()
-========================
+**$this->db->flush_cache()**
This function deletes all items from the Query Builder cache.
+:returns: void
+
+An example of caching
+---------------------
+
Here's a usage example::
$this->db->start_cache();
@@ -1033,8 +1101,12 @@
where, like, group_by, having, order_by, set
+***********************
+Resetting Query Builder
+***********************
+
$this->db->reset_query()
-========================
+------------------------
Resetting Query Builder allows you to start fresh with your query without
executing it first using a method like $this->db->get() or $this->db->insert().
@@ -1063,4 +1135,6 @@
.. note:: Double calls to ``get_compiled_select()`` while you're using the
Query Builder Caching functionality and NOT resetting your queries
will results in the cache being merged twice. That in turn will
- i.e. if you're caching a ``select()`` - select the same field twice.
\ No newline at end of file
+ i.e. if you're caching a ``select()`` - select the same field twice.
+
+:returns: void