QT Sqlite UPDATE statement prepare error

Question

I am trying to prepare a SQL statement using QT's built-in Sqlite engine.

The following statement:

UPDATE collections SET collection_type=:v1 WHERE 
(collections.collection_name = 'asfg')

fails in QSqlQuery's prepare statement (prepare returns false).

QSqlError err = db.lastError(); gives no error message...

However if I execute the same statement (by replacing :v1 with a number) in the sqlite prompt it succeeds.

What am I doing wrongly?

Edit:

What I was doing wrongly was to not to have checked the database structure. The table was missing. Too bad I can't downvote my own post :(

Evgeny · Accepted Answer · 2016-02-29 20:07:43Z

2

Replace :v1 with ? and then use

query.addBindValue(v1);

v1 is variable containing value.

edited Feb 29, 2016 at 20:07

answered Feb 29, 2016 at 15:38

Evgeny

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6 Comments

Murphy Over a year ago

The colon instead of a question mark is a valid placeholder in SQLite, and seems valid in QSqlQuery, too. However this wouldn't make the prepare statement fail.

CL. Over a year ago

And ?v1 is not a valid placeholder.

Evgeny Over a year ago

@Murphy please don't make any more changes to my post. Your edits was invalid.

Murphy Over a year ago

@CL Indeed, it isn't; mea culpa. "?" and addBindValue(v1) should work together, and ":v1" and bindValue(":v1", v1) should, too, but obviously you're not supposed to mix them.

Evgeny Over a year ago

@CL previous version is not what I wrote. That was invalid edit. Now it fixed.

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