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Diffstat (limited to 'user_guide_src/source/database/results.rst')
| -rw-r--r-- | user_guide_src/source/database/results.rst | 272 |
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.
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