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。
ODBC_TYPE
(integer)
ODBC_BINMODE_PASSTHRU
(integer)
ODBC_BINMODE_RETURN
(integer)
ODBC_BINMODE_CONVERT
(integer)
SQL_ODBC_CURSORS
(integer)
SQL_CUR_USE_DRIVER
(integer)
SQL_CUR_USE_IF_NEEDED
(integer)
SQL_CUR_USE_ODBC
(integer)
SQL_CONCURRENCY
(integer)
SQL_CONCUR_READ_ONLY
(integer)
SQL_CONCUR_LOCK
(integer)
SQL_CONCUR_ROWVER
(integer)
SQL_CONCUR_VALUES
(integer)
SQL_CURSOR_TYPE
(integer)
SQL_CURSOR_FORWARD_ONLY
(integer)
SQL_CURSOR_KEYSET_DRIVEN
(integer)
SQL_CURSOR_DYNAMIC
(integer)
SQL_CURSOR_STATIC
(integer)
SQL_KEYSET_SIZE
(integer)
SQL_CHAR
(integer)
SQL_VARCHAR
(integer)
SQL_LONGVARCHAR
(integer)
SQL_DECIMAL
(integer)
SQL_NUMERIC
(integer)
SQL_BIT
(integer)
SQL_TINYINT
(integer)
SQL_SMALLINT
(integer)
SQL_INTEGER
(integer)
SQL_BIGINT
(integer)
SQL_REAL
(integer)
SQL_FLOAT
(integer)
SQL_DOUBLE
(integer)
SQL_BINARY
(integer)
SQL_VARBINARY
(integer)
SQL_LONGVARBINARY
(integer)
SQL_DATE
(integer)
SQL_TIME
(integer)
SQL_TIMESTAMP
(integer)
SQL_TYPE_DATE
(integer)
SQL_TYPE_TIME
(integer)
SQL_TYPE_TIMESTAMP
(integer)
SQL_BEST_ROWID
(integer)
SQL_ROWVER
(integer)
SQL_SCOPE_CURROW
(integer)
SQL_SCOPE_TRANSACTION
(integer)
SQL_SCOPE_SESSION
(integer)
SQL_NO_NULLS
(integer)
SQL_NULLABLE
(integer)
SQL_INDEX_UNIQUE
(integer)
SQL_INDEX_ALL
(integer)
SQL_ENSURE
(integer)
SQL_QUICK
(integer)