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Diffstat (limited to 'user_guide_src/source/database')
| -rw-r--r-- | user_guide_src/source/database/active_record.rst | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/user_guide_src/source/database/active_record.rst b/user_guide_src/source/database/active_record.rst index e1fc00bc5..5555a30bc 100644 --- a/user_guide_src/source/database/active_record.rst +++ b/user_guide_src/source/database/active_record.rst @@ -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()`_. + + $this->db->get_where() ====================== @@ -540,6 +571,41 @@ object. .. note:: All values are escaped automatically producing safer queries. +$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()`_. + $this->db->insert_batch() ========================= @@ -717,6 +783,14 @@ array of values, the third parameter is the where key. .. note:: All values are escaped automatically producing safer queries. +$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->get_compiled_insert()`_. + ************* Deleting Data @@ -784,6 +858,13 @@ Generates a truncate SQL string and runs the query. .. 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->get_compiled_insert()`_. *************** Method Chaining @@ -854,3 +935,31 @@ Here's a usage example:: where, like, group_by, having, order_by, set + +******************* +Reset Active Record +******************* + +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; |