Can't select rows after inserting into database - iphone

Question

i've got a Problem when i try to get data from the Database after inserting some data. I can't select any row from the database.
There are entries in the database but i can not get any result.
I comment out this line in AppDelegate::application:didFinishWithOptions
[dbAccess importWithDelegate:result];
and everything works just fine. But i can't find a solution to this problem.
I hope you can help me.
DatabaseAccess-Class.
#import "KejithDatabaseAccess.h"
#import "KejithEntryQueryDelegate.h"
#interface KejithDatabaseAccess (){
sqlite3 *db;
NSString *writableDatabase;
sqlite3_stmt *statement;
}
#end
#implementation KejithDatabaseAccess
-(id)init
{
if((self = [super init]))
{
// initialize database and store in _db
}
return self;
}
-(void)initializeDatabase
{
[self createEditableDatabase];
// open the database connection
if(sqlite3_open([writableDatabase UTF8String], &db) == SQLITE_OK){
NSLog(#"Database: Connection was opened successfully");
} else {
// if something went wrong clean everything up
sqlite3_close(db);
NSAssert1(0, #"Database: Failed to open database connection. Error: '%s'", sqlite3_errmsg(db));
}
}
-(void)closeDatabase
{
if(sqlite3_close(db) != SQLITE_OK){
NSAssert1(0, #"Database: Failed to close database connection. Error: '%s'", sqlite3_errmsg(db));
}
}
-(void)createEditableDatabase
{
BOOL success;
NSError *error;
NSFileManager *fileManager = [NSFileManager defaultManager];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [paths objectAtIndex:0];
// create writable database and store path for later use
writableDatabase = [documentsDir stringByAppendingPathComponent:#"main-rw.db"];
success = [fileManager fileExistsAtPath: writableDatabase];
// if writable database already exists return
if(success) return;
// the editable database does not exist
// copy the default DB to the application
// documents directory
NSString *defaultPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:#"main.db"];
success = [fileManager copyItemAtPath:defaultPath toPath:writableDatabase error:&error];
if(!success){
NSAssert1(0, #"Database: Failed to create writable database file: '%#'.", [error localizedDescription]);
}
}
-(NSMutableArray *)queryWithDelegate
{
[self initializeDatabase];
// do we have an delegate?
if(![self delegate])
return nil;
NSMutableArray *result = [[self delegate] query:db];
[self closeDatabase];
return result;
}
-(void)importWithDelegate:(NSMutableArray *)collection
{
[self initializeDatabase];
[[self delegate] import:collection into:db];
sqlite3_finalize(statement);
[self closeDatabase];
}
-(sqlite3 *)getWritableDatabase
{
return db;
}
#end
Database Delegate-Class
#import "KejithEntryQueryDelegate.h"
#import "KejithEntry.h"
#interface KejithEntryQueryDelegate ()
#property sqlite3 *database;
#end
#implementation KejithEntryQueryDelegate
#synthesize sql;
#synthesize statement;
-(id)init
{
if((self = [super init])){
[self initSQL];
}
return self;
}
-(void)initSQL
{
sql = "SELECT _id, entry_title, entry_description, entry_phone, entry_fax, entry_email, entry_website FROM entry";
}
-(NSMutableArray *)query:(sqlite3 *)database
{
// store database
[self setDatabase:database];
// initialize array to store found objects
NSMutableArray *entries = [[NSMutableArray alloc] init];
// prepare sql statement
int sqlResult = sqlite3_prepare_v2(database, sql, -1, &statement, NULL);
if(sqlResult == SQLITE_OK){
while(sqlite3_step(statement) == SQLITE_ROW){
// allocate object to store row
KejithEntry *entry = [[KejithEntry alloc] init];
// get data from columns
NSMutableString *title = [NSMutableString stringWithString:
[NSString stringWithUTF8String:(char *) sqlite3_column_text(statement, 1)]];
NSMutableString *description = [NSMutableString stringWithString:
[NSString stringWithUTF8String:(char *) sqlite3_column_text(statement, 2)]];
NSMutableString *phone = [NSMutableString stringWithString:
[NSString stringWithUTF8String:(char *) sqlite3_column_text(statement, 3)]];
NSMutableString *fax = [NSMutableString stringWithString:
[NSString stringWithUTF8String:(char *) sqlite3_column_text(statement, 4)]];
NSMutableString *email = [NSMutableString stringWithString:
[NSString stringWithUTF8String:(char *) sqlite3_column_text(statement, 5)]];
NSMutableString *website = [NSMutableString stringWithString:
[NSString stringWithUTF8String:(char *) sqlite3_column_text(statement, 5)]];
// set data in object
[entry setId:[NSNumber numberWithInt: sqlite3_column_int(statement, 0)]];
[entry setTitle:title];
[entry setDescription:description];
[entry setPhone:phone];
[entry setFax:fax];
[entry setEmail:email];
[entry setWebsite:website];
// put object into array
[entries addObject:entry];
}
// finalize the statement to release its resources
sqlite3_finalize(statement);
} else {
// log errors
NSLog(#"Database: Problem Occured in KejithEntryQueryDelegate.m");
NSLog(#"Database: Result Code: %d", sqlResult);
NSLog(#"Database: SQL-Error: %s", sqlite3_errmsg(database));
}
return entries;
}
-(void)import:(NSMutableArray *)collection into:(sqlite3 *)database
{
if([collection count] == 0)
return;
for(KejithEntry *entry in collection){
[self importEntry:entry into:database];
}
}
-(void)importEntry:(KejithEntry *)entry into:(sqlite3 *)database
{
sql = "INSERT INTO entry (entry_id, entry_title, entry_description, entry_phone, entry_fax, entry_email, entry_website, enty_latitude, entry_longitude, entry_category_id) \
VALUES \
(0,?,?,?,?,?,?,0,0,0);";
int sqlResult = sqlite3_prepare_v2(database, sql, -1, &statement, NULL);
sqlite3_bind_text(statement, 1, [[entry title] UTF8String], -1, SQLITE_STATIC);
sqlite3_bind_text(statement, 2, [[entry getDescription] UTF8String], -1, SQLITE_STATIC);
sqlite3_bind_text(statement, 3, [[entry phone] UTF8String], -1, SQLITE_STATIC);
sqlite3_bind_text(statement, 4, [[entry fax] UTF8String], -1, SQLITE_STATIC);
sqlite3_bind_text(statement, 5, [[entry email] UTF8String], -1, SQLITE_STATIC);
sqlite3_bind_text(statement, 6, [[entry website] UTF8String], -1, SQLITE_STATIC);
if(sqlite3_step(statement) != SQLITE_DONE){
NSLog(#">> Database: Failed to insert into Database");
NSLog(#"SQL Error Message: %s", sqlite3_errmsg(database));
}
sqlite3_finalize(statement);
}
#end
AppDelegate::application:didFinishWithLaunchingOptions
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
// create delegate for entry xml parsing
id delegate = [[KejithEntryXmlDelegate alloc] init];
KejithXmlParser *parser = [[KejithXmlParser alloc] initWithUrl:[[NSURL alloc] initWithString:entryXmlUrl]];
KejithDatabaseAccess *dbAccess = [[KejithDatabaseAccess alloc] init];
KejithEntryQueryDelegate *dbEntryDelegate = [[KejithEntryQueryDelegate alloc] init];
// set delegate to parse xml file
[parser setDelegate:delegate];
// set delegate to query data to/from database
[dbAccess setDelegate:dbEntryDelegate];
// get results of xml parsing
NSMutableArray *result = [parser parse];
NSLog(#"Count of ParseResult: %d", [result count]);
[dbAccess importWithDelegate:result];
NSLog(#"Count of DatabaseResult: %d", [[dbAccess queryWithDelegate] count]);
return YES;
}
Console-Output without [dbAccess importWithDelegate:result] commented out:
2013-12-08 15:59:44.035 staedteApp[30202:70b] Database: Connection was opened successfully
2013-12-08 15:59:44.048 staedteApp[30202:70b] Database: Connection was opened successfully
2013-12-08 15:59:44.049 staedteApp[30202:70b] Count of DatabaseResult: 0
Console-Output with [dbAccess importWithDelegate:result] commented out:
2013-12-08 16:17:18.084 staedteApp[30267:70b] Database: Connection was opened successfully
2013-12-08 16:17:18.091 staedteApp[30267:70b] Count of DatabaseResult: 50
EDIT #1 -----
Updated KejithEntryQueryDelegate::importEntry:into
-(void)importEntry:(KejithEntry *)entry into:(sqlite3 *)database
{
sql = "INSERT INTO entry (entry_id, entry_title, entry_description, entry_phone, entry_fax, entry_email, entry_website, enty_latitude, entry_longitude, entry_category_id) \
VALUES \
(0,?,?,?,?,?,?,0,0,0);";
int sqlResult = sqlite3_prepare_v2(database, sql, -1, &statement, NULL);
if(sqlResult != SQLITE_DONE){
sqlite3_bind_text(statement, 1, [[entry title] UTF8String], -1, SQLITE_STATIC);
sqlite3_bind_text(statement, 2, [[entry getDescription] UTF8String], -1, SQLITE_STATIC);
sqlite3_bind_text(statement, 3, [[entry phone] UTF8String], -1, SQLITE_STATIC);
sqlite3_bind_text(statement, 4, [[entry fax] UTF8String], -1, SQLITE_STATIC);
sqlite3_bind_text(statement, 5, [[entry email] UTF8String], -1, SQLITE_STATIC);
sqlite3_bind_text(statement, 6, [[entry website] UTF8String], -1, SQLITE_STATIC);
int sqlStepResult;
if((sqlStepResult = sqlite3_step(statement)) != SQLITE_DONE){
NSLog(#">> Database: Failed to insert into Database");
NSLog(#"SQL Error Message: %s", sqlite3_errmsg(database));
NSLog(#"SQL Step Result: %d", sqlStepResult);
}
} else {
NSLog(#"Database: Problem Occured in KejithEntryQueryDelegate.m step");
NSLog(#"Database: Result Code: %d", sqlResult);
NSLog(#"Database: SQL-Error: %s", sqlite3_errmsg(database));
}
sqlite3_finalize(statement);
}

Answer 1

The issue is that you're using an instance variable for sql, setting it to the SELECT statement when you create KejithEntryQueryDelegate, changing it to an INSERT statement in the importEntry:into: method, but when you call query:, even though the code clearly assumes it should be SELECT statement, the sql is still the INSERT statement.
By looking at the result code of sqlite3_step (point 3, below) one can quickly identify the issue. Since sqlResult != DONE, you want to log the issue and it reports "entry.entry_title may not be NULL" (which doesn't make sense in a SELECT statement, which made me realize that the old INSERT statement was still in the sql variable).
My original answer, based upon a glance at the code is below. Point #3 is the critical observation.
Just looking at the code, I don't see anything that would obviously cause the behavior you describe. If I follow you correctly, you're saying that if you do not import data, 50 records are found, but if you do attempt to import the data, not only do you not see new data, but suddenly nothing is found (including the records that were already there). Is that really what you're saying? That's curious behavior. If this is, in fact, the issue, that would lead me to suspect that the attempt to import is causing the subsequent attempt to read to fail.
The only obvious SQLite issue here is that importWithDelegate should not be calling sqlite3_finalize. I don't even see why KejithDatabaseAccess has a sqlite3_stmt, as you don't prepare any statements in that class. Perhaps calling sqlite3_finalize with some invalid sqlite3_stmt causes problems?
There are a few minor things here:
The importEntry:into: should presumably check the result of sqlite3_prepare_v2 statement. Elsewhere, you confirm that the prepare succeeded before proceeding, but not here.
The query method is storing the email address into the web site property.
I'd also save the result of sqlite3_step in the query method so that you could check for errors, e.g.:
while((sqlResult = sqlite3_step(statement)) == SQLITE_ROW) {
// do all of your updating of entries here
}
if (sqlResult != SQLITE_DONE) {
NSLog(#"Database: Problem Occured in KejithEntryQueryDelegate.m step");
NSLog(#"Database: Result Code: %d", sqlResult);
NSLog(#"Database: SQL-Error: %s", sqlite3_errmsg(database));
}
Right now, if your sqlite3_step method failed, you'd never know.