Re: Cant read second table from same sqlite database iphone
Re: Cant read second table from same sqlite database iphone
- Subject: Re: Cant read second table from same sqlite database iphone
- From: Ben Trumbull <email@hidden>
- Date: Sun, 11 Apr 2010 11:37:41 -0700
I'm afraid I can't be much more help if you don't have the return codes from each of the SQLite statements. I do note in the second method, you're asking for column values out of order, which is pretty unusual.
- Ben
On Apr 10, 2010, at 6:42 PM, charisse napeÿfffff1as wrote:
> I was able to successfully retrieve data on the first table. But I can't seem to retrieve from the second table. I know it has data inside it because I used an SQLite Browser to view the data. I also tried performing queries there and it worked fine. Only when I used the queries in the code that it doesn't work.
>
> Below is the code writing the database in the Users/Documents folder for Iphone
>
> - (void) createDatabaseIfNeeded
> {
> NSError * error;
>
> //gets access to the file system
> NSFileManager * fileManager = [NSFileManager defaultManager];
>
> // gets the complete users document directory path
> NSArray * paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
>
> // gets the first path in the array
> NSString * documentsDirectory = [paths objectAtIndex:0];
>
> // create the complete path for the database file
> NSString * databasePath = [documentsDirectory stringByAppendingString:@"/Database.sql"];
>
> DebugLog("databasePath = %s\n",[databasePath UTF8String]);
>
> // check if file exists or not
> BOOL success = [fileManager fileExistsAtPath:databasePath];
>
> if (success) return;
>
> // the database does not exist so copy it in the users documents directory
> NSString * dbPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"/Database.sql"];
>
> DebugLog("dbpath is %s\n",[dbPath UTF8String]);
>
> //copy the database file to ther users docuement directory
>
> success = [fileManager copyItemAtPath:dbPath toPath:databasePath error:&error];
>
> if (!success)
> NSAssert(0,@"Failed to copy Database!\n");
> }
>
>
> From: Ben Trumbull <email@hidden>
> To: email@hidden
> Cc: Cocoa dev <email@hidden>
> Sent: Sunday, April 11, 2010 9:27:46
> Subject: re: Cant read second table from same sqlite database iphone
>
> > Hello All,
> >
> > I am having trouble reading the second table from my database because it returns nothing even if there is data inside it.
>
> How do you know it has data inside it ? A common mistake is to try to write to databases in the read only part of an application's sandbox on the iphone. Where in the sandbox is the database ?
>
> > - (NSMutableArray*) getProvinces
> > {
> > NSMutableArray * data = [[NSMutableArray alloc] init];
> > const char * sql = "SELECT * FROM Provinces";
> > sqlite3_stmt * statement;
> >
> > //prepare the select statement
> > int returnValue = sqlite3_prepare_v2(mDatabase, sql, -1, &statement, NULL);
> >
> > DebugLog("return value = %d\n",returnValue);
> >
> > if (returnValue == SQLITE_OK)
> > {
> > //sqlite3_bind_int(statement, 1, regionID);
> > //loop all the rows returned by the query
> > while (sqlite3_step(statement) == SQLITE_ROW)
> > {
>
>
> You don't check the return codes here properly. sqlite3_prepare_v2() can return SQLITE_BUSY, or SQLITE_SCHEMA, or SQLITE_MISUSE. More importantly, you don't check if sqlite3_step() returns SQLITE_DONE which would indicate that you have 0 rows in this table.
>
> - Ben
>
>
>
>
> New Email names for you!
> Get the Email name you've always wanted on the new @ymail and @rocketmail.
> Hurry before someone else does!
- Ben
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