访问PHP数组对象中的项

Question

I have an array of the record retrieved from a SQL server database stored in an object $result. I will like to access each item in the array object and print it out to the screen. How can I achieve this? My attempt is below

$result = $DB->get_records_sql("SELECT  rawname, ID FROM mdl_tag where tagType = 'institution'"); 
$result = array();
        foreach ($result as $ $value) {
        echo $value;
        );
    }

Answer 1

Here is the correct code:

// Get results from table 'tag', where 'tagtype' matches 'institution', with no sorting and returning fields 'id' and 'rawname'.
$results = $DB->get_records('tag', ['tagtype' => 'institution'], '', 'id, rawname');
foreach ($results as $value) {
    echo $value->rawname;
}

So, there are a number of issues:

1. Use get_records, unless you really need to use get_records_sql.
2. If you do need to use get_records_sql, then the table is called {tag} not mdl_tag, otherwise you'll run into problems on any server that uses a prefix other than 'mdl_' (e.g. when running phpunit or behat tests).
3. Writing $result = array(); immediately before looping through the result will throw away the details from the database and replace them with an empty array
4. The results from get_records (or get_records_sql) are an array containing objects, each of which contains the values for the requested fields, so you need to access the individual value, not try to echo the entire object
5. All database fields in Moodle are lowercase, so 'tagtype' not 'tagType', 'id' not 'ID'.