FieldFlags - Hhvm — ContextQMD

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Returns the flags of the field (column)

Hack

public function fieldFlags(
  mixed $field,
): int;

This gets the bitwise OR of the flags that are set for a given column.

See here for the possible flags.

Parameters

mixed $field - the field index (int) or field name (string).

Returns

int - The flags of the column as an int.

Examples

The following example shows how to use AsyncMysqlRowBlock::fieldFlags to get the bitwise OR combination of the flags that are set for the userID field. The flags are as follows:

Flag Value	Flag Description	Int Value
NOT_NULL_FLAG	Field cannot be NULL	1
PRI_KEY_FLAG	Field is part of a primary key	2
UNIQUE_KEY_FLAG	Field is part of a unique key	4
MULTIPLE_KEY_FLAG	Field is part of a nonunique key	8
BLOB_FLAG	Field is a BLOB or TEXT (deprecated)	16
UNSIGNED_FLAG	Field has the UNSIGNED attribute	32
ZEROFILL_FLAG	Field has the ZEROFILL attribute	64
BINARY_FLAG	Field has the BINARY attribute	128
AUTO_INCREMENT_FLAG	Field has the AUTO_INCREMENT attribute	256
ENUM_FLAG	Field is an ENUM	512
SET_FLAG	Field is a SET	1024
TIMESTAMP_FLAG	Field is a TIMESTAMP (deprecated)	2048
NO_DEFAULT_VALUE_FLAG	Field has no default value; see additional notes following table	4096
PART_KEY_FLAG	Field is at least part of a key	16384
NUM_FLAG	Field is numeric; see additional notes following table	32768

See: http://mflib.org/mysql/include/mysql_com.h

This is an example of what could have been used to create the table from where we are getting our field flags

CREATE TABLE test_table (
userID SMALLINT UNSIGNED ZEROFILL NOT NULL AUTO_INCREMENT,
name VARCHAR(40) NOT NULL,
age SMALLINT NULL,
email VARCHAR(60) NULL,
PRIMARY KEY (userID)
);

basic-usage.hack

use \Hack\UserDocumentation\API\Examples\AsyncMysql\ConnectionInfo as CI;

async function connect(
  \AsyncMysqlConnectionPool $pool,
): Awaitable<\AsyncMysqlConnection> {
  return await $pool->connect(
    CI::$host,
    CI::$port,
    CI::$db,
    CI::$user,
    CI::$passwd,
  );
}
async function simple_query(): Awaitable<int> {
  $pool = new \AsyncMysqlConnectionPool(darray[]);
  $conn = await connect($pool);
  $result = await $conn->query('SELECT * FROM test_table WHERE userID < 50');
  $conn->close();
  // A call to $result->rowBlocks() actually pops the first element of the
  // row block Vector. So the call actually mutates the Vector.
  $row_blocks = $result->rowBlocks();
  if ($row_blocks->count() > 0) {
    // An AsyncMysqlRowBlock
    $row_block = $row_blocks[0];
    return $row_block->fieldFlags('userID'); // int
  } else {
    return -1;
  }
}

<<__EntryPoint>>
async function run(): Awaitable<void> {
  $r = await simple_query();
  \var_dump($r);
}
```.hhvm.expectf
int(%d)
```.example.hhvm.out
int(49763)
```.skipif
await \Hack\UserDocumentation\API\Examples\AsyncMysql\skipif_async();