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Diffstat (limited to 'user_guide_src/source/database/active_record.rst')
| -rw-r--r-- | user_guide_src/source/database/active_record.rst | 230 |
1 files changed, 191 insertions, 39 deletions
diff --git a/user_guide_src/source/database/active_record.rst b/user_guide_src/source/database/active_record.rst index e1fc00bc5..c04e67d2a 100644 --- a/user_guide_src/source/database/active_record.rst +++ b/user_guide_src/source/database/active_record.rst @@ -45,7 +45,7 @@ You'll notice that the above function is assigned to a variable named $query, which can be used to show the results:: $query = $this->db->get('mytable'); - + foreach ($query->result() as $row) { echo $row->title; @@ -54,6 +54,37 @@ $query, which can be used to show the results:: Please visit the :doc:`result functions <results>` page for a full discussion regarding result generation. +$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:: + + $sql = $this->db->get_compiled_select('mytable'); + echo $sql; + + // Produces string: SELECT * FROM mytable + +The second parameter enables you to set whether or not the active record query +will be reset (by default it will be—just like `$this->db->get()`):: + + echo $this->db->limit(10,20)->get_compiled_select('mytable', FALSE); + // Produces string: SELECT * FROM mytable LIMIT 20, 10 + // (in MySQL. Other databases have slightly different syntax) + + echo $this->db->select('title, content, date')->get_compiled_select(); + + // Produces string: SELECT title, content, date FROM mytable + +The key thing to notice in the above example is that the second query did not +utilize `$this->db->from()`_ and did not pass a table name into the first +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()`_. + + $this->db->get_where() ====================== @@ -65,8 +96,7 @@ function:: Please read the about the where function below for more information. -Note: get_where() was formerly known as getwhere(), which has been -removed +.. note:: get_where() was formerly known as getwhere(), which has been removed $this->db->select() =================== @@ -86,7 +116,7 @@ with backticks. This is useful if you need a compound select statement. :: - $this->db->select('(SELECT SUM(payments.amount) FROM payments WHERE payments.invoice_id=4') AS amount_paid', FALSE); + $this->db->select('(SELECT SUM(payments.amount) FROM payments WHERE payments.invoice_id=4') AS amount_paid', FALSE); $query = $this->db->get('mytable'); @@ -100,7 +130,7 @@ include a second parameter to rename the resulting field. $this->db->select_max('age'); $query = $this->db->get('members'); // Produces: SELECT MAX(age) as age FROM members - + $this->db->select_max('age', 'member_age'); $query = $this->db->get('members'); // Produces: SELECT MAX(age) as member_age FROM members @@ -165,9 +195,9 @@ Permits you to write the JOIN portion of your query:: $this->db->from('blogs'); $this->db->join('comments', 'comments.id = blogs.id'); $query = $this->db->get(); - + // Produces: - // SELECT * FROM blogs // JOIN comments ON comments.id = blogs.id + // SELECT * FROM blogs JOIN comments ON comments.id = blogs.id Multiple function calls can be made if you need several joins in one query. @@ -194,7 +224,7 @@ methods: :: - $this->db->where('name', $name); // Produces: WHERE name = 'Joe' + $this->db->where('name', $name); // Produces: WHERE name = 'Joe' Notice that the equal sign is added for you. @@ -206,7 +236,7 @@ methods: $this->db->where('name', $name); $this->db->where('title', $title); $this->db->where('status', $status); - // WHERE name = 'Joe' AND title = 'boss' AND status = 'active' + // WHERE name = 'Joe' AND title = 'boss' AND status = 'active' #. **Custom key/value method:** You can include an operator in the first parameter in order to @@ -215,7 +245,7 @@ methods: :: $this->db->where('name !=', $name); - $this->db->where('id <', $id); // Produces: WHERE name != 'Joe' AND id < 45 + $this->db->where('id <', $id); // Produces: WHERE name != 'Joe' AND id < 45 #. **Associative array method:** @@ -223,7 +253,7 @@ methods: $array = array('name' => $name, 'title' => $title, 'status' => $status); $this->db->where($array); - // Produces: WHERE name = 'Joe' AND title = 'boss' AND status = 'active' + // Produces: WHERE name = 'Joe' AND title = 'boss' AND status = 'active' You can include your own operators using this method as well: @@ -324,7 +354,7 @@ searches. :: - $this->db->like('title', 'match'); // Produces: WHERE title LIKE '%match%' + $this->db->like('title', 'match'); // Produces: WHERE title LIKE '%match%' If you use multiple function calls they will be chained together with AND between them:: @@ -341,7 +371,7 @@ searches. $this->db->like('title', 'match', 'before'); // Produces: WHERE title LIKE '%match' $this->db->like('title', 'match', 'after'); // Produces: WHERE title LIKE 'match%' - $this->db->like('title', 'match', 'both'); // Produces: WHERE title LIKE '%match%' + $this->db->like('title', 'match', 'both'); // Produces: WHERE title LIKE '%match%' #. **Associative array method:** @@ -413,7 +443,7 @@ Permits you to write the HAVING portion of your query. There are 2 possible syntaxes, 1 argument or 2:: $this->db->having('user_id = 45'); // Produces: HAVING user_id = 45 - $this->db->having('user_id', 45); // Produces: HAVING user_id = 45 + $this->db->having('user_id', 45); // Produces: HAVING user_id = 45 You can also pass an array of multiple values as well:: @@ -456,7 +486,7 @@ Or multiple function calls can be made if you need multiple fields. :: $this->db->order_by("title", "desc"); - $this->db->order_by("name", "asc"); // Produces: ORDER BY title DESC, name ASC + $this->db->order_by("name", "asc"); // Produces: ORDER BY title DESC, name ASC .. note:: order_by() was formerly known as orderby(), which has been @@ -488,7 +518,7 @@ where(), or_where(), like(), or_like(), etc. Example:: echo $this->db->count_all_results('my_table'); // Produces an integer, like 25 $this->db->like('title', 'match'); $this->db->from('my_table'); - echo $this->db->count_all_results(); // Produces an integer, like 17 + echo $this->db->count_all_results(); // Produces an integer, like 17 $this->db->count_all() ====================== @@ -499,6 +529,54 @@ Submit the table name in the first parameter. Example:: echo $this->db->count_all('my_table'); // Produces an integer, like 25 ************** +Query grouping +************** + +Query grouping allows you to create groups of WHERE clauses by enclosing them in parentheses. This will allow +you to create queries with complex WHERE clauses. Nested groups are supported. Example: + + $this->db->select('*')->from('my_table') + ->group_start() + ->where('a', 'a') + ->or_group_start() + ->where('b', 'b') + ->where('c', 'c') + ->group_end() + ->group_end() + ->where('d', 'd') + ->get(); + + // Generates: + // SELECT * FROM (`my_table`) WHERE ( `a` = 'a' OR ( `b` = 'b' AND `c` = 'c' ) ) AND `d` = 'd' + +.. note:: groups need to be balanced, make sure every group_start() is matched by a group_end(). + +$this->db->group_start() +======================== + +Starts a new group by adding an opening parenthesis to the WHERE clause of the query. + +$this->db->or_group_start() +=========================== + +Starts a new group by adding an opening parenthesis to the WHERE clause of the query, prefixing it with 'OR'. + +$this->db->not_group_start() +============================ + +Starts a new group by adding an opening parenthesis to the WHERE clause of the query, prefixing it with 'NOT'. + +$this->db->or_not_group_start() +=============================== + +Starts a new group by adding an opening parenthesis to the WHERE clause of the query, prefixing it with 'OR NOT'. + +$this->db->group_end() +====================== + +Ends the current group by adding an closing parenthesis to the WHERE clause of the query. + +************** Inserting Data ************** @@ -514,7 +592,7 @@ function. Here is an example using an array:: 'name' => 'My Name', 'date' => 'My date' ); - + $this->db->insert('mytable', $data); // Produces: INSERT INTO mytable (title, name, date) VALUES ('My title', 'My name', 'My date') @@ -530,7 +608,7 @@ Here is an example using an object:: var $date = 'My Date'; } */ - + $object = new Myclass; $this->db->insert('mytable', $object); // Produces: INSERT INTO mytable (title, content, date) VALUES ('My Title', 'My Content', 'My Date') @@ -540,6 +618,41 @@ object. .. note:: All values are escaped automatically producing safer queries. +$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. + +Example:: + + $data = array( + 'title' => 'My title', + 'name' => 'My Name', + 'date' => 'My date' + ); + + $sql = $this->db->set($data)->get_compiled_insert('mytable'); + echo $sql; + + // Produces string: INSERT INTO mytable (title, name, date) VALUES ('My title', 'My name', 'My date') + +The second parameter enables you to set whether or not the active record query +will be reset (by default it will be--just like `$this->db->insert()`_):: + + echo $this->db->set('title', 'My Title')->get_compiled_insert('mytable', FALSE); + + // Produces string: INSERT INTO mytable (title) VALUES ('My Title') + + echo $this->db->set('content', 'My Content')->get_compiled_insert(); + + // Produces string: INSERT INTO mytable (title, content) VALUES ('My Title', 'My Content') + +The key thing to notice in the above example is that the second query did not +utlize `$this->db->from()`_ nor did it pass a table name into the first +parameter. The reason this worked is because the query has not been executed +using `$this->db->insert()`_ which resets values or reset directly using +`$this->db->reset_query()`_. + $this->db->insert_batch() ========================= @@ -559,7 +672,7 @@ function. Here is an example using an array:: 'date' => 'Another date' ) ); - + $this->db->insert_batch('mytable', $data); // Produces: INSERT INTO mytable (title, name, date) VALUES ('My title', 'My name', 'My date'), ('Another title', 'Another name', 'Another date') @@ -587,7 +700,7 @@ based on whether you are doing an insert or an update:: $this->db->set('name', $name); $this->db->set('title', $title); $this->db->set('status', $status); - $this->db->insert('mytable'); + $this->db->insert('mytable'); **set()** will also accept an optional third parameter ($escape), that will prevent data from being escaped if set to FALSE. To illustrate the @@ -609,7 +722,7 @@ You can also pass an associative array to this function:: 'title' => $title, 'status' => $status ); - + $this->db->set($array); $this->db->insert('mytable'); @@ -622,7 +735,7 @@ Or an object:: var $date = 'My Date'; } */ - + $object = new Myclass; $this->db->set($object); $this->db->insert('mytable'); @@ -644,7 +757,7 @@ is an example using an array:: 'name' => $name, 'date' => $date ); - + $this->db->where('id', $id); $this->db->update('mytable', $data); // Produces: // UPDATE mytable // SET title = '{$title}', name = '{$name}', date = '{$date}' // WHERE id = $id @@ -658,7 +771,7 @@ Or you can supply an object:: var $date = 'My Date'; } */ - + $object = new Myclass; $this->db->where('id', $id); $this->db->update('mytable', $object); @@ -699,14 +812,14 @@ Here is an example using an array:: ) ); - $this->db->update_batch('mytable', $data, 'title'); + $this->db->update_batch('mytable', $data, 'title'); - // Produces: + // Produces: // UPDATE `mytable` SET `name` = CASE // WHEN `title` = 'My title' THEN 'My Name 2' // WHEN `title` = 'Another title' THEN 'Another Name 2' // ELSE `name` END, - // `date` = CASE + // `date` = CASE // WHEN `title` = 'My title' THEN 'My date 2' // WHEN `title` = 'Another title' THEN 'Another date 2' // ELSE `date` END @@ -717,6 +830,14 @@ array of values, the third parameter is the where key. .. note:: All values are escaped automatically producing safer queries. +$this->db->get_compiled_update() +================================ + +This works exactly the same way as ``$this->db->get_compiled_insert()`` except +that it produces an UPDATE SQL string instead of an INSERT SQL string. + +For more information view documentation for `$this->db->get_compiled_insert()`_. + ************* Deleting Data @@ -737,7 +858,7 @@ the data to the second parameter of the function:: $this->db->where('id', $id); $this->db->delete('mytable'); - + // Produces: // DELETE FROM mytable // WHERE id = $id @@ -762,7 +883,7 @@ $this->db->empty_table() Generates a delete SQL string and runs the query.:: - $this->db->empty_table('mytable'); // Produces // DELETE FROM mytable + $this->db->empty_table('mytable'); // Produces: DELETE FROM mytable $this->db->truncate() @@ -773,18 +894,25 @@ Generates a truncate SQL string and runs the query. :: $this->db->from('mytable'); - $this->db->truncate(); - - // or - + $this->db->truncate(); + + // or + $this->db->truncate('mytable'); - + // Produce: - // TRUNCATE mytable + // TRUNCATE mytable .. note:: If the TRUNCATE command isn't available, truncate() will execute as "DELETE FROM table". +$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()`_. + *************** Method Chaining *************** @@ -797,8 +925,6 @@ multiple functions. Consider this example:: ->limit(10, 20) ->get('mytable'); -.. note:: Method chaining only works with PHP 5. - .. _ar-caching: ********************* @@ -839,11 +965,11 @@ Here's a usage example:: $this->db->stop_cache(); $this->db->get('tablename'); //Generates: SELECT `field1` FROM (`tablename`) - + $this->db->select('field2'); $this->db->get('tablename'); //Generates: SELECT `field1`, `field2` FROM (`tablename`) - + $this->db->flush_cache(); $this->db->select('field2'); $this->db->get('tablename'); @@ -854,3 +980,29 @@ Here's a usage example:: where, like, group_by, having, order_by, set +$this->db->reset_query() +======================== + +Resetting Active Record allows you to start fresh with your query without +executing it first using a method like $this->db->get() or $this->db->insert(). +Just like the methods that execute a query, this will *not* reset items you've +cached using `Active Record Caching`_. + +This is useful in situations where you are using Active Record to generate SQL +(ex. ``$this->db->get_compiled_select()``) but then choose to, for instance, +run the query:: + + // Note that the second parameter of the get_compiled_select method is FALSE + $sql = $this->db->select(array('field1','field2')) + ->where('field3',5) + ->get_compiled_select('mytable', FALSE); + + // ... + // Do something crazy with the SQL code... like add it to a cron script for + // later execution or something... + // ... + + $data = $this->db->get()->result_array(); + + // Would execute and return an array of results of the following query: + // SELECT field1, field1 from mytable where field3 = 5; |