Small. Fast. Reliable.
Choose any three.
#define SQLITE_DETERMINISTIC 0x000000800
#define SQLITE_DIRECTONLY 0x000080000
#define SQLITE_SUBTYPE 0x000100000
#define SQLITE_INNOCUOUS 0x000200000
These constants may be ORed together with the
preferred text encoding as the fourth argument
to sqlite3_create_function(), sqlite3_create_function16(), or
sqlite3_create_function_v2().
- SQLITE_DETERMINISTIC
-
The SQLITE_DETERMINISTIC flag means that the new function always gives
the same output when the input parameters are the same.
The abs() function is deterministic, for example, but
randomblob() is not. Functions must
be deterministic in order to be used in certain contexts such as
with the WHERE clause of partial indexes or in generated columns.
SQLite might also optimize deterministic functions by factoring them
out of inner loops.
- SQLITE_DIRECTONLY
-
The SQLITE_DIRECTONLY flag means that the function may only be invoked
from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
schema structures such as CHECK constraints, DEFAULT clauses,
expression indexes, partial indexes, or generated columns.
The SQLITE_DIRECTONLY flags is a security feature which is recommended
for all application-defined SQL functions, and especially for functions
that have side-effects or that could potentially leak sensitive
information.
- SQLITE_INNOCUOUS
-
The SQLITE_INNOCUOUS flag means that the function is unlikely
to cause problems even if misused. An innocuous function should have
no side effects and should not depend on any values other than its
input parameters. The abs() function is an example of an
innocuous function.
The load_extension() SQL function is not innocuous because of its
side effects.
SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
exactly the same. The random() function is an example of a
function that is innocuous but not deterministic.
Some heightened security settings
(SQLITE_DBCONFIG_TRUSTED_SCHEMA and PRAGMA trusted_schema=OFF)
disable the use of SQL functions inside views and triggers and in
schema structures such as CHECK constraints, DEFAULT clauses,
expression indexes, partial indexes, and generated columns unless
the function is tagged with SQLITE_INNOCUOUS. Most built-in functions
are innocuous. Developers are advised to avoid using the
SQLITE_INNOCUOUS flag for application-defined functions unless the
function has been carefully audited and found to be free of potentially
security-adverse side-effects and information-leaks.
- SQLITE_SUBTYPE
-
The SQLITE_SUBTYPE flag indicates to SQLite that a function may call
sqlite3_value_subtype() to inspect the sub-types of its arguments.
Specifying this flag makes no difference for scalar or aggregate user
functions. However, if it is not specified for a user-defined window
function, then any sub-types belonging to arguments passed to the window
function may be discarded before the window function is called (i.e.
sqlite3_value_subtype() will always return 0).
See also lists of
Objects,
Constants, and
Functions.