CODEWITHSUNDEEP
sqlitedata-binding
Petriborg
Petriborg

Reputation: 2960

How to prevent Sqlite unbound parameters interpreted as NULL

As the Sqlite docs specify, unbound parameters in prepared statements are interpreted as NULL - my question is this then:

Is there a way to have Sqlite ensure that all parameters have been bound at least once, thereby ensuring none were missed by accident?

It is better to get an error and require calls to sqlite3_bind_null(statement_, col); then to get a subtle error because I forgot to call sqlite3_bind_* on the where clause of an update statement!

Upvotes: 2

Views: 797

Answers (1)

thkala
thkala

Reputation: 86333

It is not possible to differentiate unbound parameters from parameters set to NULL using the current SQLite libraries.

If you have a look at the C source code for sqlite3_bind_null(), you will find that it simply calls the internal SQLite function that unbinds a parameter. Therefore there is no way to tell the two cases apart.

The only solution for this would be to wrap the SQLite C API functions with your own functions that will do a bit of book-keeping. You can bundle a bitmap with each sqlite3_stmt structure, with each bit set to true if and only if the corresponding parameter is bound. You would have to create wrappers for at least the sqlite3_bind_*() functions and sqlite3_clear_bindings().

Upvotes: 3

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