PDONULLORACLE

PDONULLORACLE is a symbolic constant that appears in some Oracle-related PHP libraries, particularly those that implement the PDO (PHP Data Objects) interface or OCI bindings for Oracle databases. It is not part of the official PHP PDO API and public PHP documentation does not standardize its value or usage. Instead, it is seen in older or vendor-specific code, and its exact definition can vary between versions and drivers such as pdo_oci or OCI8 wrappers.

In practice, PDONULLORACLE is intended to denote a NULL binding for Oracle prepared statements. When binding parameters, code may test for this constant to ensure the database receives a NULL rather than an empty string or another placeholder. Modern PHP code typically uses PDO::PARAM_NULL or similar higher-level abstractions; PDONULLORACLE may be exposed only within low-level driver code.

Because it is not standardized, relying on PDONULLORACLE can reduce portability across drivers and PHP versions. If you encounter it, consult the specific driver's documentation or source code to understand how it maps to Oracle NULL and how it interacts with type binding, character semantics, and Oracle's NULL handling.

See also: PDO, OCI8, pdo_oci, Oracle database, NULL value binding.