I have implemented NSOPERATIONQUEUE By sending request and i can able to download response from server but the problem is i cant able to parallely process the sqlite to insert/update the response,i am getting Database Locked Error.So Can anyone suggest me a solution to work with database for insertion/updation of my downloaded response??
I have created a NSOperation Class as PageLoadOperation and i will pass request 7 times to that NSOperation class and add it to queue as below
PageLoadOperation *pageLoad=[[PageLoadOperation alloc]initWithRequest:theRequest];
[queue addOperation:pageLoad];
In Main i can able to send request by below NSURLConnection
[NSURLConnection sendAsynchronousRequest:theRequest
queue:[NSOperationQueue mainQueue]
completionHandler:^(NSURLResponse *response, NSData *data, NSError *error)
{
[self openConnection];
[self doSomethingWithData:data];
[self closeConnection];
}];
and in doSomethingWithData method i will insert/update the response by converting data to NSString I have separately created method for opening the database connection and once insertion/updation completed i will closeconnection by following methods
-(BOOL)openConnection
{
database=nil;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);
documentsDir = [paths objectAtIndex:0];
if(sqlite3_open([[documentsDir stringByAppendingPathComponent:#"DataStore"] UTF8String], &database)==SQLITE_OK)
{
NSLog(#"DB Connection Established successfully");
return YES;
}
else
{
NSLog(#"DB not connected");
return NO;
}
}
-(BOOL)closeConnection
{
NSLog(#"%#",documentsDir);
if(sqlite3_close(database)==SQLITE_OK)
{
NSLog(#"DB Connection closed successfully");
return YES;
}
else
{
NSLog(#"Error Failed to close DB because %s",sqlite3_errmsg(database));
return NO;
}
}
My Insertion Method is :
- (void) addToDatabase :(NSString*) sqlstmt :(NSArray *)params
{
sqlite3_stmt *addStmt;
if(sqlite3_prepare_v2(database, [sqlstmt UTF8String], -1, &addStmt, NULL) != SQLITE_OK)
NSAssert1(0, #"Error while creating add statement. '%s'", sqlite3_errmsg(database));
else
{
for (i=1; i<=[params count]; i++)
{
sqlite3_bind_text(addStmt, i,[[params objectAtIndex:i-1] UTF8String], -1, SQLITE_TRANSIENT);
}
}
if(SQLITE_DONE != sqlite3_step(addStmt))
NSAssert1(0, #"Error while inserting data. '%s'", sqlite3_errmsg(database));
else
NSLog(#"%lld",sqlite3_last_insert_rowid(database));
sqlite3_finalize(addStmt);
}
While adding to database i am getting database locked error because while one response is open the database and inserting into database parallely another response try to open the database connection,so how can i resolve this problem?
Related
I'm desperate.
I create an application using sqlite an it was working fine until I submit an update to the apple store.
when my application is reinstalled and I tried to open a db connection I got an "out of memory" issue.
I've tried lots of stuff to solve this issue, but until today I was unable to solve this.
I use the code below to open db's connection:
-(Boolean)openConectionSQLiteDb
{
if (sqlite3_open([[GeneralFunction getInfoFromUserDefault:#"dbpath"] UTF8String], &db) != SQLITE_OK)
{
NSLog(#"Failed to open database!");
NSLog(#"%s",sqlite3_errmsg(statement));
//[GeneralFunction setDb:[[DbInteraction alloc] init:[GeneralFunction getDbName]]];
{
NSLog(#"Failed to open database! >>%#",[GeneralFunction getInfoFromUserDefault:#"dbpath"]);
// NSLog(#"222%s",sqlite3_errmsg(statement));
}
sqlite3_finalize(statement);
return false;
}
else
{
sqlite3_exec(db, "PRAGMA foreign_keys = on", NULL, NULL, NULL);
return true;
}
return false;
}
And the code below is used to insert date on the database:
-(Boolean)insertOrReplace:(NSDictionary *)elementoToInsert inTable:(NSString *)tableName
{
if([self openConectionSQLiteDb])
{
NSString * insert = [self createInsertStringWith:elementoToInsert in:tableName];
insert = [insert stringByReplacingOccurrencesOfString:#"INSERT" withString:#"INSERT OR REPLACE "];
const char *insert_stmt = [insert UTF8String];
sqlite3_prepare_v2(db, insert_stmt,
-1, &statement, NULL);
if (sqlite3_step(statement) == SQLITE_DONE)
{
sqlite3_finalize(statement);
sqlite3_close(db);
// NSLog(#"FECHOU");
return true;
}
NSLog(#"INSERT ERROR %s",sqlite3_errmsg(db));
sqlite3_finalize(statement);
}
sqlite3_close(db);
NSLog(#"FECHOU");
return false;
}
I'm also use this code to copy the Db file to a writable path when it necessary:
-(id)init:(NSString *) dbName
{
self = [super init];
nomeDb = dbName;
BOOL success;
NSFileManager *filemngr = [[NSFileManager alloc] init];
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
NSString *documentDirectory = [paths objectAtIndex:0];
NSString *writableDbPath = [documentDirectory stringByAppendingPathComponent:nomeDb];
// NSLog(#"%#",[GeneralFunction getInfoFromUserDefault:#"dbpath"]);
NSString * lastPath =[GeneralFunction getInfoFromUserDefault:#"dbpath"];
success = [filemngr fileExistsAtPath:lastPath];
if(!success)
{
NSLog(#"Arquivo não existe nesse Directorio >%#",lastPath);
success = [filemngr fileExistsAtPath:writableDbPath];
if(!success)
{
NSLog(#"Arquivo não existe nesse Directorio >%#",writableDbPath);
NSString *defaultDbPath = [[[NSBundle mainBundle] resourcePath]stringByAppendingPathComponent:nomeDb];
success = [filemngr copyItemAtPath:defaultDbPath toPath:writableDbPath error:&error];
NSLog(#"Copiou Para :%#",writableDbPath);
if (!success)
{
NSLog(#"Arquivo não existe nesse Directorio pela seguanda vez >%#",writableDbPath);
//[status setText:[error localizedDescription]];
/* UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Error!"
message:[error localizedDescription]
delegate:nil
cancelButtonTitle:#"OK"
otherButtonTitles:nil];
[alert show];*/
}
else
{
NSLog(#"Achou 2");
NSMutableDictionary * dic = [[NSMutableDictionary alloc] init];
// NSLog(#"%#",writableDbPath);
[dic setObject:writableDbPath forKey:#"dbpath"];
[GeneralFunction saveTeacherInfo:dic];
writablePath = writableDbPath;
}
}
else
{
NSLog(#"Banco esta em %#",writableDbPath);
}
}
else{
NSLog(#"Achou");
}
// [bd executeUpdate:#"PRAGMA foreign_keys=ON"];
return self;
}
So when I install the application for the first time, it works fine. But if I run the applications again (It happens when I submit an update too) I got the LOG error "Failed to open database out of memory".
Someone please help me, I'm almost getting fired.
PS: I'm sorry for my terrible English. ;D
sqlite reports "out of memory" errors incorrectly at times. Usually if this occurs after an app update, it's because you have a bug in your sqlite access code. If your database schema has changed between app versions, but you didn't make sure that your database calls are backwards-compatible, you will frequently see this error.
If your CREATE TABLE statements aren't followed by ALTER TABLE statements to bring your schema up to speed when the CREATE fails because the table already exists, you run the risk of making database calls that are not backwards-compatible.
YEAH GUYS, finally I could solve my issue.
It was happening because when I was checking if there was a Database already copied in my writable path, in the TRUE condition I forgot to update my internal path that refers to the DB. For that reason when I was trying to open a connection, it was returning me the error because I was looking for the database in wrong place.
What motivates the occurs "Error database is locked" when ever I open and close the database and also finalize all statement?
Code:
//Opening database
if (sqlite3_open([[self filePath] UTF8String], &database) != SQLITE_OK) {
sqlite3_close(database);
NSAssert(0, #"Database failed to open.");
}else{
NSLog(#"Database opened.");
}
//Performing operation
char * err;
if(sqlite3_exec(database, [sql UTF8String], NULL, NULL, &err) != SQLITE_OK) {
sqlite3_close(database);
NSAssert(0, #"----> Could not perform operation on table people. Error %# <----", [NSString stringWithUTF8String:err]);
} else {
NSLog(#"----> Operation performed on table people <----");
}
sqlite3_close(database);
I'm having an issue opening my sqlite database for an iPhone app I'm writing. I thought I followed the tutorials verbatim but for some reason I am getting an "Out of memory" error.
-(NSString *) filepath{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
return [[paths objectAtIndex:0] stringByAppendingPathComponent:#"db.sqlite"];
}
-(sqlite3*)openDB{
if(db == NULL){
sqlite3 *newDBConnection;
if(sqlite3_open([[self filepath] UTF8String], &newDBConnection) != SQLITE_OK){
sqlite3_close(db);
NSLog(#"%s SQL error '%s' (%1d)", __FUNCTION__, sqlite3_errmsg(db), sqlite3_errcode(db));
db = NULL;
}
else{
NSLog(#"db opened");
}
}
return db;
}
DB is an ivar and I am calling db = [self openDB]; in the initialization method.
The sqlite3_open is failing because you are using NSDocumentationDirectory instead of NSDocumentDirectory.
The reason you're receiving the "Out of memory" error is that sqlite3_open is updating newDBConnection, but the sqlite3_errmsg is trying to use db (which is still NULL). And whenever you call sqlite3_errmsg with a NULL for the sqlite3 pointer, SQLite somewhat confusingly returns an "Out of memory" message.
Also note that even if you fix the two above issues, note that you are calling sqlite3_errmsg after performing sqlite3_close. Make sure to get your error message before you call sqlite3_close.
E.g. I would suggest:
- (BOOL)openDB {
if (db == NULL) {
int rc;
if ((rc = sqlite3_open([[self filepath] UTF8String], &db)) != SQLITE_OK) {
NSLog(#"%s SQL error '%s' (%d)", __FUNCTION__, sqlite3_errmsg(db), rc);
sqlite3_close(db);
db = NULL;
return false; // open failed
} else {
NSLog(#"db opened");
return true; // open successful
}
}
return true; // already open
}
Note, a minor point, given that sqlite3_open returns the error code, I would just save that directly, rather than calling sqlite3_errcode to get the code that was just returned.
I have UIDocument in iCloud ubiquitous container and I need to append data to file while saving document. I override readFromURL:: and writeContents::::: method according UIDocument documentation:
-(BOOL) writeContents:(id)contents toURL:(NSURL*)url forSaveOperation:(UIDocumentSaveOperation)saveOperation originalContentsURL:(NSURL*)originalContentsURL error:(NSError *__autoreleasing *)outError
{
NSFileCoordinator* coordinator = [[NSFileCoordinator alloc] initWithFilePresenter:self];
NSError* error = nil;
[coordinator coordinateWritingItemAtURL:url options:0 error:&error byAccessor:^(NSURL *newURL) {
NSData* data = contents; //correct, non-empty NSData
///[data writeToFile:newURL :] works, but overwrite original file
NSOutputStream* stream =[[NSOutputStream alloc] initWithURL:newURL append:YES];
if (stream)
{
NSInteger written = [stream write:data.bytes maxLength:data.length];
if (written != data.length)
{
//failed here, written == -1
NSLog(#"Write data to UIDocument failed: %#, error: %#", newURL, stream.streamError);
}
}
else
{
NSLog(#"Write data to iCloudDocument failed: %#", newURL);
}
}];
if (error)
{
NSLog(#"Coordinated write failed %#, error: %#", url, error);
*outError = error;
}
return error == nil;
}
Accessor block has different newURL, for example:
url: file:///private/var/mobile/Library/Mobile%20Documents/XXXXXXX~com~test~test/test.doc
newURL: file:///private/var/mobile/Applications/5631D484-7661-4E9E-A342-B25297FC0E18/tmp/(A%20Document%20Being%20Saved%20By%20test%20)/test.doc.
[stream write::] failed, because newURL file dosn't exists and I can't append data, only create file with all document's content.
Document editing code:
NSURL* url = [self.containerURL URLByAppendingPathComponent:kCloudDocumentName];
MyDocument* document = [[MyDocument alloc] initWithFileURL:url];
[document openWithCompletionHandler:^(BOOL success) {
if (success)
{
//update some document data
[self updateData:document completion:nil];
[document closeWithCompletionHandler:^(BOOL success) {
//failed here!
}];
}
}];
MyDocument exists in ubiquitous container at url and document has Normal state.
How I can do incremental writing in this case? Whats wrong?
After changing data in your UIDocumnet you can use:
-[UIDocumnet saveToURL:UIDocumnet.fileURL forSaveOperation:UIDocumentSaveForOverwriting completionHandler:nil];
Not sure, it's right or not but it works in my app. If it's wrong, correct me please somebody.
You may need to overwrite this method in your subclass of UIDocumnet:
- (id) contentsForType:(NSString *)typeName error:(NSError **)outError
I'm using this to do an Update statement in a test iOS App, the log outputs 'Success' but theres no change in the database. Could anyone point me in the right direction? It'd be greatly appreciated.
I'm brand new to this so please forgive my probably appallingly written code.
#try {
NSFileManager *fileMgr = [NSFileManager defaultManager];
NSString *dbPath = [[[NSBundle mainBundle] resourcePath ]stringByAppendingPathComponent:#"chars.sqlite3"];
BOOL success = [fileMgr fileExistsAtPath:dbPath];
if(!success)
{
NSLog(#"Cannot locate database file '%#'.", dbPath);
}
if(!(sqlite3_open([dbPath UTF8String], &db) == SQLITE_OK))
{
NSLog(#"An error has occured: %s", sqlite3_errmsg(db));
}
const char *sql = "UPDATE characters SET level = 'testing' WHERE id='1'";
sqlite3_stmt *sqlStatement;
if(sqlite3_prepare(db, sql, -1, &sqlStatement, NULL) != SQLITE_OK)
{
NSLog(#"Problem with prepare statement: %s", sqlite3_errmsg(db));
}else{
if (sqlite3_step(sqlStatement) == SQLITE_DONE){
NSLog(#"Success");
}
}
sqlite3_finalize(sqlStatement);
}
#catch (NSException *exception) {
NSLog(#"Problem with prepare statement: %s", sqlite3_errmsg(db));
}
#finally {
sqlite3_close(db);
}
The problem is that you're opening the database from the bundle, which is read-only. You should
Check for the existence of the database in the Documents folder.
If not there, copy the database from the bundle to the Documents folder.
Now, open the database from the Documents folder.