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