下列常量由此扩展定义，且仅在此扩展编译入 PHP 或在运行时动态载入时可用。
FBSQL_ASSOC
(integer)
FBSQL_NUM
(integer)
FBSQL_BOTH
(integer)
FBSQL_LOCK_DEFERRED
(integer)
FBSQL_LOCK_OPTIMISTIC
(integer)
FBSQL_LOCK_PESSIMISTIC
(integer)
FBSQL_ISO_READ_UNCOMMITTED
(integer)
FBSQL_ISO_READ_COMMITTED
(integer)
FBSQL_ISO_REPEATABLE_READ
(integer)
FBSQL_ISO_SERIALIZABLE
(integer)
FBSQL_ISO_VERSIONED
(integer)
FBSQL_UNKNOWN
(integer)
FBSQL_STOPPED
(integer)
FBSQL_STARTING
(integer)
FBSQL_RUNNING
(integer)
FBSQL_STOPPING
(integer)
FBSQL_NOEXEC
(integer)
FBSQL_LOB_DIRECT
(integer)
FBSQL_LOB_HANDLE
(integer)