Why can't I update statement in SQLite? - iphone

Question

Can anyone help me with this code snippet:
-(void) updateData:(NSString*)value1:(NSString*)value2
{
sqlite3* database;
databaseName = #"AppDB.sqlite";
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [documentPaths objectAtIndex:0];
databasePath = [documentsDir stringByAppendingPathComponent:databaseName];
int databaseReturnCode = sqlite3_open([databasePath UTF8String], &database);
if(databaseReturnCode == SQLITE_OK) {
sqlite3_stmt *updateStmt;
const char *sql = "update PersonalInfo Set FirstName = ?,LastName = ? Where id = '1'";
//sqlite3_prepare_v2(database, sql, -1, &updateStmt, NULL);
sqlite3_prepare(database, sql, -1, &updateStmt,nil);
sqlite3_bind_text(updateStmt, 1, [value1 UTF8String], -1, SQLITE_TRANSIENT);
sqlite3_bind_text(updateStmt, 2, [value2 UTF8String], -1, SQLITE_TRANSIENT);
printf( "Update PersonalInfo| error or not an error? : %s\n", sqlite3_errmsg(database) );
while(sqlite3_step(updateStmt) == SQLITE_ROW)
{
NSString *aFirstName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(updateStmt, 1)];
NSString *aLastName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(updateStmt, 2)];
ProfileInfo *profile = [[ProfileInfo alloc]initWithFirstName:(NSString*)aFirstName LastName:(NSString*)aLastName];
[personalInfo addObject:profile];
[profile release];
}
sqlite3_reset(updateStmt);
sqlite3_finalize(updateStmt);
}
}
sqlite3_close(database);
}
It doesn't enter the while loop.
But if I remove the while loop and
enclose the code in a try-catch block and I get this exception:
+[NSString stringWithUTF8String:]: NULL cString

Answer 1

An sqlite_step while-loop is inappropriate for an update statement.
From the documentation at sqlite.org:
sqlite3_step() This routine is used to evaluate a prepared statement
that has been previously created by the sqlite3_prepare() interface.
The statement is evaluated up to the point where the first row of
results are available. To advance to the second row of results, invoke
sqlite3_step() again. Continue invoking sqlite3_step() until the
statement is complete. Statements that do not return results (ex:
INSERT, UPDATE, or DELETE statements) run to completion on a single
call to sqlite3_step().
Check your return value of sqlite_step. It should be something like SQLITE_DONE rather than SQLITE_ROW.