pg_field_prtlen - PHP code example

PHP Function pg_field_prtlen - How to Use it Correctly

PHP has lots of built-in functions that allow you to perform many common programming tasks without writing any code. But if you use them incorrectly, you can write code that is difficult to understand or debug. This article will help you use php function pg_field_prtlen correctly and avoid these pitfalls.

The first thing to understand about PHP functions is that they are not the same as methods in object-oriented languages. A method is part of a class and works with arguments, but a function is a separate statement that can work on a single expression. When you call a function, it runs the expression on its own and returns the value of that expression.

Another important concept to understand is how scope affects a function. When you declare a variable in a function definition, it defines the value/memory-space of that variable within the scope of the function. For example, the variable $fruit in the code sample above is used both inside and outside of the function. Because the global keyword is not used, $fruit represents a different value/memory space inside and outside of the function.

The pg_field_prtlen() function is similar to the pg_field_name() function, but it returns the actual printed length (number of characters) of a field in a PostgreSQL result resource. It also accepts an argument that specifies the row number in the result - row numbering starts at 0. This function has been deprecated and replaced by the canonical version.

pg_field_prtlen example

$a['last OID'] = pg_last_oid($result);

        $fields = pg_num_fields($result);

        for ($i = 0; $i < $fields; ++$i) {
            $field = [
                'name' => pg_field_name($result, $i),
                'table' => sprintf('%s (OID: %s)', pg_field_table($result, $i), pg_field_table($result, $i, true)),
                'type' => sprintf('%s (OID: %s)', pg_field_type($result, $i), pg_field_type_oid($result, $i)),
                'nullable' => (bool) pg_field_is_null($result, $i),
                'storage' => pg_field_size($result, $i).' bytes',
                'display' => pg_field_prtlen($result, $i).' chars',
            ];
            if (' (OID: )' === $field['table']) {
                $field['table'] = null;
            }
            if ('-1 bytes' === $field['storage']) {
                $field['storage'] = 'variable size';
            } elseif ('1 bytes' === $field['storage']) {
                $field['storage'] = '1 byte';
            }
            if ('1 chars' === $field['display']) {
                $field['display'] = '1 char';
            }