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| <h1>Generating Query Results</h1> |
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| <p>There are several ways to generate query results:</p> |
| |
| <h2>result()</h2> |
| |
| <p>This function returns the query result as an array of <strong>objects</strong>, or <strong>an empty array</strong> on failure. |
| |
| Typically you'll use this in a foreach loop, like this:</p> |
| |
| <code> |
| $query = $this->db->query("YOUR QUERY");<br /> |
| <br /> |
| foreach ($query->result() as $row)<br /> |
| {<br /> |
| echo $row->title;<br /> |
| echo $row->name;<br /> |
| echo $row->body;<br /> |
| }</code> |
| |
| <p>The above <dfn>function</dfn> is an alias of <dfn>result_object()</dfn>.</p> |
| |
| <p>If you run queries that might <strong>not</strong> produce a result, you are encouraged to test the result first:</p> |
| |
| <code> |
| $query = $this->db->query("YOUR QUERY");<br /> |
| <br /> |
| if ($query->num_rows() > 0)<br /> |
| {<br /> |
| foreach ($query->result() as $row)<br /> |
| {<br /> |
| echo $row->title;<br /> |
| echo $row->name;<br /> |
| echo $row->body;<br /> |
| }<br /> |
| } |
| </code> |
| |
| <h2>result_array()</h2> |
| |
| <p>This function 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:</p> |
| <code> |
| $query = $this->db->query("YOUR QUERY");<br /> |
| <br /> |
| foreach ($query->result_array() as $row)<br /> |
| {<br /> |
| echo $row['title'];<br /> |
| echo $row['name'];<br /> |
| echo $row['body'];<br /> |
| }</code> |
| |
| |
| <h2>row()</h2> |
| |
| <p>This function 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 <strong>object</strong>. Here's a usage example:</p> |
| <code> |
| $query = $this->db->query("YOUR QUERY");<br /> |
| <br /> |
| if ($query->num_rows() > 0)<br /> |
| {<br /> |
| $row = $query->row(); |
| <br /><br /> |
| echo $row->title;<br /> |
| echo $row->name;<br /> |
| echo $row->body;<br /> |
| } |
| </code> |
| |
| <p>If you want a specific row returned you can submit the row number as a digit in the first parameter:</p> |
| |
| <code>$row = $query->row(<dfn>5</dfn>);</code> |
| |
| |
| <h2>row_array()</h2> |
| |
| <p>Identical to the above <var>row()</var> function, except it returns an array. Example:</p> |
| |
| <code> |
| $query = $this->db->query("YOUR QUERY");<br /> |
| <br /> |
| if ($query->num_rows() > 0)<br /> |
| {<br /> |
| $row = $query->row_array(); |
| <br /><br /> |
| echo $row['title'];<br /> |
| echo $row['name'];<br /> |
| echo $row['body'];<br /> |
| } |
| </code> |
| |
| |
| <p>If you want a specific row returned you can submit the row number as a digit in the first parameter:</p> |
| |
| <code>$row = $query->row_array(<dfn>5</dfn>);</code> |
| |
| |
| <p>In addition, you can walk forward/backwards/first/last through your results using these variations:</p> |
| |
| <p> |
| <strong>$row = $query->first_row()</strong><br /> |
| <strong>$row = $query->last_row()</strong><br /> |
| <strong>$row = $query->next_row()</strong><br /> |
| <strong>$row = $query->previous_row()</strong> |
| </p> |
| |
| <p>By default they return an object unless you put the word "array" in the parameter:</p> |
| |
| <p> |
| <strong>$row = $query->first_row('array')</strong><br /> |
| <strong>$row = $query->last_row('array')</strong><br /> |
| <strong>$row = $query->next_row('array')</strong><br /> |
| <strong>$row = $query->previous_row('array')</strong> |
| </p> |
| |
| |
| |
| <h1>Result Helper Functions</h1> |
| |
| |
| <h2>$query->num_rows()</h2> |
| <p>The number of rows returned by the query. Note: In this example, <dfn>$query</dfn> is the variable that the query result object is assigned to:</p> |
| |
| <code>$query = $this->db->query('SELECT * FROM my_table');<br /><br /> |
| echo $query->num_rows(); |
| </code> |
| |
| <h2>$query->num_fields()</h2> |
| <p>The number of FIELDS (columns) returned by the query. Make sure to call the function using your query result object:</p> |
| |
| <code>$query = $this->db->query('SELECT * FROM my_table');<br /><br /> |
| echo $query->num_fields(); |
| </code> |
| |
| |
| |
| <h2>$query->free_result()</h2> |
| <p>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. Example: |
| </p> |
| |
| <code>$query = $this->db->query('SELECT title FROM my_table');<br /><br /> |
| foreach ($query->result() as $row)<br /> |
| {<br /> |
| echo $row->title;<br /> |
| }<br /> |
| $query->free_result(); // The $query result object will no longer be available<br /> |
| <br /> |
| $query2 = $this->db->query('SELECT name FROM some_table');<br /><br /> |
| $row = $query2->row();<br /> |
| echo $row->name;<br /> |
| $query2->free_result(); // The $query2 result object will no longer be available |
| </code> |
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