iOS, SQLite: can't read from the DB - ios

I have an SQLite database, I can open it with SQLite browser, execute queries to it etc. But I can't get any data from it in my Xcode project.
NSString *databaseName = #"dbFile.db";
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [documentPaths objectAtIndex:0];
NSString *databasePath = [documentsDir stringByAppendingPathComponent:databaseName];
sqlite3 *database;
if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {
NSLog(#"db is ok"); // works just fine
const char *sqlStatement = "SELECT table.column FROM table";
sqlite3_stmt *compiledStatement;
if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
NSLog(#"OK"); // nothing happens
}
sqlite3_close(database);
}
The very same query executed from SQLite browser for Mac works just fine.

sqlite3_open doesn't report all errors until you start accessing the data. For example just about any filename and path will pass without errors.
Are you sure the database is in the Documents folder? It's not there by default.
Perhaps it's in the main bundle?
Try
NSString *databaseName = [[NSBundle mainBundle] pathForResource:#"dbFile" ofType:#"db"];

Related

Unable to delete table from sqlite database in iOS

I have written a delete query in method applicationDidEnterBackground of AppDelegate class. But when i stop the simulator it does not delete the database table. I want to delete the database tables when the app enters in the background or when the app terminates. Here is my applicationDidEnterBackground method for delete table query.
- (void)applicationDidEnterBackground:(UIApplication *)application {
sqlite3 *database;
NSArray * dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString* docsDir = [dirPaths objectAtIndex:0];
NSString * databasePath = [docsDir stringByAppendingPathComponent:#"sssw.sqlite"];
if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK)
{
NSString *sqlStatement_userInfo =[NSString stringWithFormat:#"DELETE * from SHOPDATA"];
sqlite3_stmt *compiledStatement;
if(sqlite3_prepare_v2(database, [sqlStatement_userInfo UTF8String], -1, &compiledStatement, NULL) == SQLITE_OK)
{
NSLog(#"table deleted");
}
else
{
NSLog(#"Unable to delete table");
}
sqlite3_finalize(compiledStatement);
}
sqlite3_close(database);
}
please tell me what should i do and what am i doing wrong here.
Any help will be appreciated.

(Objective C) Save changes in sqlite database

I'm creating an app for my school project that has to write data to my sqlite database. It works, as long as the app is running active but as soon as the app closes, my added data is gone and when I want to read this data this will not work off course. I included both my loadData and saveData methods. The two database paths are the same in both functions so it's not that I'm writing my data elsewhere. I really can't find the solution or the problem. I even get the insert success in my output, so the insert is successful.
- (void) saveData:(id)sender{
NSString *sqldb = [[NSBundle mainBundle] pathForResource:#"PXLate" ofType:#"sqlite3"];
sqlite3_stmt *stmt;
NSString *queryInsert = #"INSERT INTO assignments (name, lesson, dueDate, notification, start, at) VALUES ('abc','abc', 'abc', 1, 'abc', 'abc')";
NSLog(#"%#",sqldb);
NSLog(#"%#",queryInsert);
if(sqlite3_open([sqldb UTF8String], &_PXLate) == SQLITE_OK)
{
sqlite3_prepare_v2(_PXLate, [queryInsert UTF8String], -1, &stmt, NULL);
if(sqlite3_step(stmt)==SQLITE_DONE)
{
NSLog(#"insert success");
}
else
{
NSLog(#"insert un success");
NSAssert1(0, #"Error: failed to prepare statement with message '%s'.", sqlite3_errmsg(_PXLate));
}
int success=sqlite3_step(stmt);
if (success == SQLITE_ERROR)
{
NSAssert1(0, #"Error: failed to insert into the database with message '%s'.", sqlite3_errmsg(_PXLate));
//[_PXLate save:&error];
} sqlite3_finalize(stmt);
}
sqlite3_close(_PXLate);
}
and my loadData function
- (void) loadData:(id)sender
{
//path for database
NSString *sqldb = [[NSBundle mainBundle] pathForResource:#"PXLate" ofType:#"sqlite3"];
//check if present
NSFileManager*fm=[NSFileManager defaultManager];
NSLog(#"path: %#", sqldb);
const char *dbpath = [sqldb UTF8String];
sqlite3_stmt *statement;
if (sqlite3_open(dbpath, &_PXLate) == SQLITE_OK)
{
NSString *querySQL = [NSString stringWithFormat: #"SELECT * FROM assignments WHERE name='abc'", _label.text];
const char *query_stmt = [querySQL UTF8String];
NSLog(#"name");
NSLog(querySQL);
int response = sqlite3_prepare_v2(_PXLate, query_stmt, -1, &statement, NULL);
NSLog(#"response %d", response);
if (response == SQLITE_OK)
{
NSLog(#"name");
if (sqlite3_step(statement) == SQLITE_ROW)
{
NSString *namefield = [[NSString alloc]
initWithUTF8String:
(const char *) sqlite3_column_text(
statement, 0)];
NSLog(#"name:%#", namefield);
_label.text = namefield;
} else {
_label.text = #"Match not found";
}
sqlite3_finalize(statement);
}
sqlite3_close(_PXLate);
}
}
You have to copy your sqlite to the documents directory and then work with that. Example:
self.databaseName = #"databasename.sqlite";
// Get the path to the documents directory and append the databaseName
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [documentPaths objectAtIndex:0];
self.databasePath = [[NSString alloc]init];
self.databasePath = [documentsDir stringByAppendingPathComponent:self.databaseName];
[self checkAndCreateDatabase];
And the create method:
-(void)checkAndCreateDatabase
{
NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *databasePathFromApp = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:self.databaseName];
[fileManager copyItemAtPath:databasePathFromApp toPath:self.databasePath error:nil];
}
A couple of observations:
As Retterdesdialogs said, you should
Check for existence of database in Documents;
If not there, copy from bundle to Documents; and
Open database from Documents.
You should not open database from bundle, because on the device that folder is read-only.
In your INSERT statement you are not checking the response of sqlite3_prepare_v2, which is a very common source of errors. If this is not SQLITE_OK, you should immediately log sqlite3_errmsg, before you call sqlite3_step.
You are performing sqlite3_step twice in the INSERT statement.
In loadData, you are not logging sqlite3_errmsg if sqlite3_prepare_v2 failed. Always look at sqlite3_errmsg upon any error.

Objective-c sql error - error with statement look like empty result

hi i'm getting stuck with some code. i have a file catalog.db and a class that let me work with it. When i try to retrieve datas from the db it seems like it's empty. With several nslog i can see that it connect and enter the database, i can see it enter in it but then it won't get any value from it.
i tried to see if the query was wrong with an external DB manager software and the query works fine...
this is my class
#import "DBAccess.h"
sqlite3* database;
#implementation DBAccess
-(id)init{
self = [super init];
if (self){
[self initializeDatabase];
}
return self;
}
-(void)initializeDatabase{
NSString *path = [[NSBundle mainBundle]pathForResource:#"catalog" ofType:#"db"];
if (sqlite3_open([path UTF8String], &database) == SQLITE_OK) { NSLog(#"Opening Database"); }
else {
sqlite3_close(database);
NSAssert1(0, #"FAILED to open database '%s'", sqlite3_errmsg(database));
}
}
-(void)closeDatabase{
if (sqlite3_close(database) != SQLITE_OK){
NSAssert1(0, #"ERROR to close databse: '%s'", sqlite3_errmsg(database));
}
}
-(NSMutableArray *)getAllProduct{
NSMutableArray *products = [[NSMutableArray alloc]init];
const char *sql = "SELECT product.ID,product.Name, Manufacturer.name, product.details,product.price, product.quantityOnHand,country.country,product.image FROM product,manufacturer,country WHERE manufacturer.manufacturerID = product.manufacturerID and product.countryOfOriginID = country.countryID";
sqlite3_stmt *statement;
int sqlResult = sqlite3_prepare_v2(database, sql, -1, &statement, NULL);
NSLog(#"sqlResult: %d", sqlResult);
if (sqlResult == SQLITE_OK){
NSLog(#"sql step statement: %d",sqlite3_step(statement));
NSLog(#"QUERY DONE");
while (sqlite3_step(statement) == SQLITE_ROW){
NSLog(#"TEST");
Product *product = [[Product alloc]init];
char *name = (char *)sqlite3_column_text(statement, 1);
NSLog(#"n %s",name);
char *manufacturer = (char *)sqlite3_column_text(statement, 2);
NSLog(#"m %s", manufacturer);
char *details = (char *)sqlite3_column_text(statement, 3);
NSLog(#"d %s", details);
char *countryoforigin = (char *)sqlite3_column_text(statement, 6);
NSLog(#"%s", countryoforigin);
char *image = (char *)sqlite3_column_text(statement, 7);
NSLog(#"%s", image);
product.ID = sqlite3_column_text(statement, 0);
product.name = (name)?[NSString stringWithUTF8String:name]:#"";
product.manufacturer = (manufacturer)?[NSString stringWithUTF8String:manufacturer]:#"";
product.details = (details)?[NSString stringWithUTF8String:details]:#"";
product.price = sqlite3_column_double (statement, 4);
product.quantity = sqlite3_column_int(statement, 5);
product.countryOfOrigin = (countryoforigin)?[NSString stringWithUTF8String:countryoforigin]:#"";
product.image = (image)?[NSString stringWithUTF8String:image]:#"";
[products addObject:product];
}
sqlite3_finalize(statement);
}
else {
NSLog(#"Problem with database %d",sqlResult);
}
return products;
}
#end
this is what i get in my console
2013-08-14 12:38:58.505 Catalog[1642:c07] Opening Database
2013-08-14 12:38:58.508 Catalog[1642:c07] sqlResult: 0
2013-08-14 12:38:58.509 Catalog[1642:c07] sql step statement: 101
2013-08-14 12:38:58.509 Catalog[1642:c07] QUERY DONE
2013-08-14 12:38:58.510 Catalog[1642:c07] ()
what can be my problem? thanks
Here
NSLog(#"sql step statement: %d",sqlite3_step(statement));
you fetch already the first row (without using the result).
1)Copy the database to your documents directory...
-(void) checkAndCreateDatabase{
// Check if the SQL database has already been saved to the users phone, if not then copy it over
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [documentPaths objectAtIndex:0];
NSString *databasePath = [documentsDir stringByAppendingPathComponent:#"test.sqlite"];
BOOL success;
// Create a FileManager object, we will use this to check the status
// of the database and to copy it over if required
NSFileManager *fileManager = [NSFileManager defaultManager];
// Check if the database has already been created in the users filesystem
success = [fileManager fileExistsAtPath:databasePath];
// If the database already exists then return without doing anything
if(success) return;
// If not then proceed to copy the database from the application to the users filesystem
// Get the path to the database in the application package
NSString *databasePathFromApp = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:#"test.sqlite"];
// Copy the database from the package to the users filesystem
[fileManager copyItemAtPath:databasePathFromApp toPath:databasePath error:nil];
}
2)Then talk to database in this way.
-(void)sqliteTransaction
{
sqlite3 *database;
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [documentPaths objectAtIndex:0];
NSString *databasePath = [documentsDir stringByAppendingPathComponent:#"test.sqlite"];
// Init the animals Array
// Open the database from the users filessytem
if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {
// Setup the SQL Statement and compile it for faster access
const char *sqlStatement = "select * from me";
sqlite3_stmt *compiledStatement;
if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
// Loop through the results and add them to the feeds array
while(sqlite3_step(compiledStatement) == SQLITE_ROW) {
// Read the data from the result row
NSString *aName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];
NSLog(#"%#",aName);
// Create a new animal object with the data from the database
}
}
// Release the compiled statement from memory
sqlite3_finalize(compiledStatement);
}
sqlite3_close(database);
}
Try like this, before going to SELECT make sure the table is properly connected for selection with the open query like this
sqlite3_open(dbpath, &ProDB)
After that execute your selection. See this below sample code. Hope it will help
ex:
NSMutableArray *sessionDetails = [NSMutableArray array];
NSString *docsDir;
NSArray *dirPaths;
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];
NSString *databasePath = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent: #"cPro.db"]];
const char *dbpath = [databasePath UTF8String];
sqlite3_stmt *statement;
if (sqlite3_open(dbpath, &ProDB) == SQLITE_OK)
{
NSString *querySQL = [NSString stringWithFormat: #"SELECT * FROM USER_SESSION_INFO"];
NSLog(#"query: %#",querySQL);
const char *query_stmt = [querySQL UTF8String];
if (sqlite3_prepare_v2(ProDB, query_stmt, -1, &statement, NULL) == SQLITE_OK)
{
while(sqlite3_step(statement) == SQLITE_ROW)
{
// Your functionality.
}
}
}
i tried the method you guys suggested but i still get the same problem.
i think i found out what's causing it.
i changed my query with this:
const char *sql = "SELECT product.ID,product.Name, product.details,product.price, product.quantityOnHand,product.image FROM Product";
and this way it works... so it looks like i have trouble reading other tables...
the moment i add another table it stop working. but that's weird cause with external db manager software the query works just fine

Sqlite insert statement doesn't add records in iOS app

I am trying to execute a simple hard-coded insert statement for a SqLite database. The code works and I get a success message from my own NSLog, however, no records are added to the database. Can anyone help? THx! Viv
-(void)addFavorites{
const char *sqlInsert = "insert into rivers (stat_ID, stat_Name, state) values ('03186500','WILLIAMS RIVER','WA')";
sqlite3_stmt *statement;
sqlite3_prepare_v2(_database, sqlInsert, -1, &statement, NULL);
if(sqlite3_step(statement) == SQLITE_DONE){
NSLog(#"RECORD ADDED!");
} else {
NSLog(#"RECORD NOT ADDED!");
}
sqlite3_finalize(statement);
}
Do you have code like this in your app delegate to copy the database out of the bundle to your NSDocuments directory? Be sure to copy the database to there, then point to there when you're running your sqlite3_open, not to the bundle. The NSDocument directory will be saved when the device is synced to iTunes or iCloud, so it's the place you want your database to be for maintaining data.
NSString *databaseName = #"MyDatabase.sqlite";
NSArray *systemPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *libraryDirectory = [systemPaths objectAtIndex:0];
NSString *databaseFullPath = [libraryDirectory stringByAppendingFormat:#"%#%#",#"/",databaseName];
//copy the database to the file system if it hasn't been done yet.
NSFileManager *fileManager = [NSFileManager defaultManager];
BOOL exists = [fileManager fileExistsAtPath:databaseFullPath];
if(exists == NO)
{
NSString *dbPathInBundle = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:databaseName];
[fileManager copyItemAtPath:dbPathInBundle toPath:databaseFullPath error:nil];
}

Not able to access iOS SQLite database: sqlite3_prepare_v2 and 'no such table' sqlite3_errmsg

This is the first time I'm trying to create and access a SQLite db in iOS and I followed a tutorial, but I can't make this work. These are the steps I've followed:
Created a database through the Firefox plugin ("testDatabase") and a
table ("testTable") with several columns
Saved the "testDatabase.sqlite" file in a directory
Dragged and dropped such file into my "Supporting Files" group in my
Xcode project
Added "libsqlite3.dylib" in Build Phases > Link Binary With
Libraries
Added "-lsqlite3" in Build Settings > Linking > Other Linker Flags >
Debug and Release
In a ViewController, called this method:
-(NSString *)copyDatabaseToDocuments {
NSFileManager *fileManager = [NSFileManager defaultManager];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsPath = [paths objectAtIndex:0];
NSString *filePath = [documentsPath stringByAppendingPathComponent:#"testDatabase.sqlite"];
if ( ![fileManager fileExistsAtPath:filePath] ) {
NSString *bundlePath = [[[NSBundle mainBundle] resourcePath]
stringByAppendingPathComponent:#"testDatabase.sqlite"];
[fileManager copyItemAtPath:bundlePath toPath:filePath error:nil];
}
return filePath;
}
Then, trying to write in the database:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsPath = [paths objectAtIndex:0];
NSString *filePath = [documentsPath stringByAppendingPathComponent:#"testDatabase.sqlite"];
sqlite3 *database;
if(sqlite3_open([filePath UTF8String], &database) == SQLITE_OK) {
const char *sqlStatement = "insert into testTable (id) VALUES (?)";
sqlite3_stmt *compiledStatement;
if (sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
sqlite3_bind_int(compiledStatement, 1, newObject.ID);
}
if(sqlite3_step(compiledStatement) == SQLITE_DONE) {
sqlite3_finalize(compiledStatement);
}
}
sqlite3_close(database);
I have read several posts regarding a similar error, but nothing of what I tried has worked for me... I also tried with NSString *filePath = [[NSBundle mainBundle] pathForResource:#"testDatabase" ofType:#"sqlite"]; but it is null, and also have underplayed and redeployed my app in the simulator several times...
Thanks in advance
I finally got this working by simply deleting the app folder generated in /Users/[user]/Library/Application Support/iPhone Simulator/5.1/Applications/ to be created again when running the simulator

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