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-rw-r--r--user_guide_src/source/database/results.rst272
1 files changed, 235 insertions, 37 deletions
diff --git a/user_guide_src/source/database/results.rst b/user_guide_src/source/database/results.rst
index e0a87a851..ae81998c7 100644
--- a/user_guide_src/source/database/results.rst
+++ b/user_guide_src/source/database/results.rst
@@ -4,10 +4,17 @@ Generating Query Results
There are several ways to generate query results:
-result()
-========
+.. contents::
+ :local:
+ :depth: 2
-This function returns the query result as an array of **objects**, or
+*************
+Result Arrays
+*************
+
+**result()**
+
+This method returns the query result as an array of **objects**, or
**an empty array** on failure. Typically you'll use this in a foreach
loop, like this::
@@ -20,7 +27,7 @@ loop, like this::
echo $row->body;
}
-The above function is an alias of result_object().
+The above method is an alias of ``result_object()``.
If you run queries that might **not** produce a result, you are
encouraged to test the result first::
@@ -46,14 +53,13 @@ instantiate for each result object (note: this class must be loaded)
foreach ($query->result('User') as $user)
{
- echo $user->name; // call attributes
- echo $user->reverse_name(); // or methods defined on the 'User' class
+ echo $user->name; // access attributes
+ echo $user->reverse_name(); // or methods defined on the 'User' class
}
-result_array()
-===============
+**result_array()**
-This function returns the query result as a pure array, or an empty
+This method returns the query result as a pure array, or an empty
array when no result is produced. Typically you'll use this in a foreach
loop, like this::
@@ -66,10 +72,13 @@ loop, like this::
echo $row['body'];
}
-row()
-=====
+***********
+Result Rows
+***********
+
+**row()**
-This function returns a single result row. If your query has more than
+This method returns a single result row. If your query has more than
one row, it returns only the first row. The result is returned as an
**object**. Here's a usage example::
@@ -95,13 +104,12 @@ to instantiate the row with::
$query = $this->db->query("SELECT * FROM users LIMIT 1;");
$query->row(0, 'User');
- echo $row->name; // call attributes
+ echo $row->name; // access attributes
echo $row->reverse_name(); // or methods defined on the 'User' class
-row_array()
-===========
+**row_array()**
-Identical to the above row() function, except it returns an array.
+Identical to the above ``row()`` method, except it returns an array.
Example::
$query = $this->db->query("YOUR QUERY");
@@ -136,10 +144,11 @@ parameter:
| **$row = $query->next_row('array')**
| **$row = $query->previous_row('array')**
-.. note:: all the functions above will load the whole result into memory (prefetching) use unbuffered_row() for processing large result sets.
+.. note:: All the methods above will load the whole result into memory
+ (prefetching). Use ``unbuffered_row()`` for processing large
+ result sets.
-unbuffered_row()
-================
+**unbuffered_row()**
This method returns a single result row without prefetching the whole
result in memory as ``row()`` does. If your query has more than one row,
@@ -163,12 +172,11 @@ the returned value's type::
$query->unbuffered_row('object'); // object
$query->unbuffered_row('array'); // associative array
-***********************
-Result Helper Functions
-***********************
+*********************
+Result Helper Methods
+*********************
-$query->num_rows()
-==================
+**num_rows()**
The number of rows returned by the query. Note: In this example, $query
is the variable that the query result object is assigned to::
@@ -177,30 +185,28 @@ is the variable that the query result object is assigned to::
echo $query->num_rows();
-.. note::
- Not all database drivers have a native way of getting the total
+.. note:: Not all database drivers have a native way of getting the total
number of rows for a result set. When this is the case, all of
- the data is prefetched and count() is manually called on the
- resulting array in order to achieve the same functionality.
+ the data is prefetched and ``count()`` is manually called on the
+ resulting array in order to achieve the same result.
-$query->num_fields()
-====================
+**num_fields()**
The number of FIELDS (columns) returned by the query. Make sure to call
-the function using your query result object::
+the method using your query result object::
$query = $this->db->query('SELECT * FROM my_table');
echo $query->num_fields();
-$query->free_result()
-=====================
+**free_result()**
It frees the memory associated with the result and deletes the result
resource ID. Normally PHP frees its memory automatically at the end of
script execution. However, if you are running a lot of queries in a
particular script you might want to free the result after each query
-result has been generated in order to cut down on memory consumptions.
+result has been generated in order to cut down on memory consumption.
+
Example::
$query = $this->db->query('SELECT title FROM my_table');
@@ -209,6 +215,7 @@ Example::
{
echo $row->title;
}
+
$query->free_result(); // The $query result object will no longer be available
$query2 = $this->db->query('SELECT name FROM some_table');
@@ -217,8 +224,7 @@ Example::
echo $row->name;
$query2->free_result(); // The $query2 result object will no longer be available
-data_seek()
-===========
+**data_seek()**
This method sets the internal pointer for the next result row to be
fetched. It is only useful in combination with ``unbuffered_row()``.
@@ -233,4 +239,196 @@ TRUE on success or FALSE on failure.
$row = $query->unbuffered_row();
.. note:: Not all database drivers support this feature and will return FALSE.
- Most notably - you won't be able to use it with PDO. \ No newline at end of file
+ Most notably - you won't be able to use it with PDO.
+
+***************
+Class Reference
+***************
+
+.. class:: CI_DB_result
+
+ .. method:: result([$type = 'object'])
+
+ :param string $type: Type of requested results - array, object, or class name
+ :returns: Array containing the fetched rows
+ :rtype: array
+
+ A wrapper for the ``result_array()``, ``result_object()``
+ and ``custom_result_object()`` methods.
+
+ Usage: see `Result Arrays`_.
+
+ .. method:: result_array()
+
+ :returns: Array containing the fetched rows
+ :rtype: array
+
+ Returns the query results as an array of rows, where each
+ row is itself an associative array.
+
+ Usage: see `Result Arrays`_.
+
+ .. method:: result_object()
+
+ :returns: Array containing the fetched rows
+ :rtype: array
+
+ Returns the query results as an array of rows, where each
+ row is an object of type ``stdClass``.
+
+ Usage: see `Result Arrays`_.
+
+ .. method:: custom_result_object($class_name)
+
+ :param string $class_name: Class name for the resulting rows
+ :returns: Array containing the fetched rows
+ :rtype: array
+
+ Returns the query results as an array of rows, where each
+ row is an instance of the specified class.
+
+ .. method:: row([$n = 0[, $type = 'object']])
+
+ :param int $n: Index of the query results row to be returned
+ :param string $type: Type of the requested result - array, object, or class name
+ :returns: The requested row or NULL if it doesn't exist
+ :rtype: mixed
+
+ A wrapper for the ``row_array()``, ``row_object() and
+ ``custom_row_object()`` methods.
+
+ Usage: see `Result Rows`_.
+
+ .. method:: unbuffered_row([$type = 'object'])
+
+ :param string $type: Type of the requested result - array, object, or class name
+ :returns: Next row from the result set or NULL if it doesn't exist
+ :rtype: mixed
+
+ Fetches the next result row and returns it in the
+ requested form.
+
+ Usage: see `Result Rows`_.
+
+ .. method:: row_array([$n = 0])
+
+ :param int $n: Index of the query results row to be returned
+ :returns: The requested row or NULL if it doesn't exist
+ :rtype: array
+
+ Returns the requested result row as an associative array.
+
+ Usage: see `Result Rows`_.
+
+ .. method:: row_object([$n = 0])
+
+ :param int $n: Index of the query results row to be returned
+ :returns: The requested row or NULL if it doesn't exist
+ :rtype: stdClass
+
+ Returns the requested result row as an object of type
+ ``stdClass``.
+
+ Usage: see `Result Rows`_.
+
+ .. method:: custom_row_object($n, $type)
+
+ :param int $n: Index of the results row to return
+ :param string $class_name: Class name for the resulting row
+ :returns: The requested row or NULL if it doesn't exist
+ :rtype: $type
+
+ Returns the requested result row as an instance of the
+ requested class.
+
+ .. method:: data_seek([$n = 0])
+
+ :param int $n: Index of the results row to be returned next
+ :returns: TRUE on success, FALSE on failure
+ :rtype: bool
+
+ Moves the internal results row pointer to the desired offset.
+
+ Usage: see `Result Helper Methods`_.
+
+ .. method:: set_row($key[, $value = NULL])
+
+ :param mixed $key: Column name or array of key/value pairs
+ :param mixed $value: Value to assign to the column, $key is a single field name
+ :rtype: void
+
+ Assigns a value to a particular column.
+
+ .. method:: next_row([$type = 'object'])
+
+ :param string $type: Type of the requested result - array, object, or class name
+ :returns: Next row of result set, or NULL if it doesn't exist
+ :rtype: mixed
+
+ Returns the next row from the result set.
+
+ .. method:: previous_row([$type = 'object'])
+
+ :param string $type: Type of the requested result - array, object, or class name
+ :returns: Previous row of result set, or NULL if it doesn't exist
+ :rtype: mixed
+
+ Returns the previous row from the result set.
+
+ .. method:: first_row([$type = 'object'])
+
+ :param string $type: Type of the requested result - array, object, or class name
+ :returns: First row of result set, or NULL if it doesn't exist
+ :rtype: mixed
+
+ Returns the first row from the result set.
+
+ .. method:: last_row([$type = 'object'])
+
+ :param string $type: Type of the requested result - array, object, or class name
+ :returns: Last row of result set, or NULL if it doesn't exist
+ :rtype: mixed
+
+ Returns the last row from the result set.
+
+ .. method:: num_rows()
+
+ :returns: Number of rows in the result set
+ :rtype: int
+
+ Returns the number of rows in the result set.
+
+ Usage: see `Result Helper Methods`_.
+
+ .. method:: num_fields()
+
+ :returns: Number of fields in the result set
+ :rtype: int
+
+ Returns the number of fields in the result set.
+
+ Usage: see `Result Helper Methods`_.
+
+ .. method:: field_data()
+
+ :returns: Array containing field meta-data
+ :rtype: array
+
+ Generates an array of ``stdClass`` objects containing
+ field meta-data.
+
+ .. method:: free_result()
+
+ :rtype: void
+
+ Frees a result set.
+
+ Usage: see `Result Helper Methods`_.
+
+ .. method:: list_fields()
+
+ :returns: Array of column names
+ :rtype: array
+
+ Returns an array containing the field names in the
+ result set. \ No newline at end of file