Right way of inserting data into SQLite db iPhone

问题:

How to insert data into table in sqlite iPhone?

I am trying following, but its failing:

 NSString *query=[NSString stringWithFormat:@"insert into %@ (name) values ('%@')", table name,myName ];    sqlite3 *database;  sqlite3_stmt *createStmt = nil;  if (sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {     if (createStmt == nil) {          if (sqlite3_prepare_v2(database, [query UTF8String], -1, &createStmt, NULL) != SQLITE_OK) {             return NO;         }         sqlite3_exec(database, [query UTF8String], NULL, NULL, NULL);         return YES;     }      return YES; }else {     return NO; } 

I have created table in following manner:

create table if not exists myDets (dets_id integer primary key asc, name text); 

I am also using Firefox SQLite plugin to check db. When I try to insert record via firefox into my db it gives me following error:

Failed to insert values Exception Name: NS_ERROR_STORAGE_IOERR Exception Message: Component returned failure code: 0x80630002 (NS_ERROR_STORAGE_IOERR)        [mozIStorageStatement.execute] 

Badly stuck :(

Also, i am running this on iPhone simulator, does it matter?

Please help

Thanks in advance.

回答1:

• Use parameters and don't string format your update statement
• Add lots of tracing, check return codes and check for error codes (you're question isn't clear what error, issue you're hitting on iPhone).
• use sqlite3_errmsg to get error messages
• construct your dbPath and log it out. Ensure you can open the db from terminal under the emulator. Remember that sqlite will create a database in memory passively so if you're path is off and the db doesn't exist it can be confusing.
• print out your update statement and try it from sqlite cmdline app in terminal in the path you logged.
• if you're putting the db in the main bundle resources, it's a template and needs to be copied in order to open and write to it.

Here's an update function from a sample of mine:

- (void)updateContact: (Contact*)contact error:(NSError**)error {     if (![self ensureDatabaseOpen:error])     {         return;     }      NSLog(@">> ContactManager::updateContact");      // prep statement     sqlite3_stmt    *statement;     NSString *querySQL = @"update contacts set name=?,address=?,phone=? where id=?";     NSLog(@"query: %@", querySQL);     const char *query_stmt = [querySQL UTF8String];      // preparing a query compiles the query so it can be re-used.     sqlite3_prepare_v2(_contactDb, query_stmt, -1, &statement, NULL);          sqlite3_bind_text(statement, 1, [[contact name] UTF8String], -1, SQLITE_STATIC);     sqlite3_bind_text(statement, 2, [[contact address] UTF8String], -1, SQLITE_STATIC);     sqlite3_bind_text(statement, 3, [[contact phone] UTF8String], -1, SQLITE_STATIC);     sqlite3_bind_int64(statement, 4, [[contact id] longLongValue]);      NSLog(@"bind name: %@", [contact name]);     NSLog(@"bind address: %@", [contact address]);     NSLog(@"bind phone: %@", [contact phone]);     NSLog(@"bind int64: %qi", [[contact id] longLongValue]);      // process result     if (sqlite3_step(statement) != SQLITE_DONE)     {         NSLog(@"error: %s", sqlite3_errmsg(_contactDb));     }      sqlite3_finalize(statement); } 

In the sample, the db is copied from resources to a path and opened. Here's the ensure opened function I use to do that:

- (BOOL)ensureDatabaseOpen: (NSError **)error {     // already created db connection     if (_contactDb != nil)     {         return YES;     }      NSLog(@">> ContactManager::ensureDatabaseOpen");         if (![self ensureDatabasePrepared:error])     {         return NO;     }      const char *dbpath = [_dbPath UTF8String];      if (sqlite3_open(dbpath, &_contactDb) != SQLITE_OK &&         error != nil)     {         *error = [[[NSError alloc] initWithDomain:@"ContactsManager" code:1000 userInfo:nil] autorelease];         return NO;     }      NSLog(@"opened");      return YES; }  - (BOOL)ensureDatabasePrepared: (NSError **)error {     // already prepared     if ((_dbPath != nil) &&         ([[NSFileManager defaultManager] fileExistsAtPath:_dbPath]))     {         return YES;     }      // db in main bundle - cant edit.  copy to library if !exist     NSString *dbTemplatePath = [[NSBundle mainBundle] pathForResource:@"contacts" ofType:@"db"];     NSLog(@"%@", dbTemplatePath);      NSString *libraryPath = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) lastObject];     _dbPath = [libraryPath stringByAppendingPathComponent:@"contacts.db"];      NSLog(@"dbPath: %@", _dbPath);      // copy db from template to library     if (![[NSFileManager defaultManager] fileExistsAtPath:_dbPath])     {         NSLog(@"db not exists");         NSError *error = nil;         if (![[NSFileManager defaultManager] copyItemAtPath:dbTemplatePath toPath:_dbPath error:&error])         {             return NO;         }          NSLog(@"copied");     }          return YES;     } 

回答2:

- (NSString *) getDBPath {      NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);     NSString *documentsDir = [paths objectAtIndex:0];     return [documentsDir stringByAppendingPathComponent:@"iHadDB.sqlite"]; }  - (void) insertValueToDatabase {      NSString *dbPath =[self getDBPath];      NSString *select_Meal = dummy_select_Meal;     NSString *dateTime = dummy_date_Time;     NSString *location = dummy_location;     NSString *mealItem = dummy_mealItem;      if (sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK) {          const char *sqlDB = "Insert into iHad(Mealtype,DateAndTime,Location,Mealitem) VALUES (?,?,?,?)";          if(sqlite3_prepare_v2(database, sqlDB, -1, &addStmt, NULL) != SQLITE_OK)             NSAssert1(0, @"Error while creating add statement. '%s'", sqlite3_errmsg(database));          sqlite3_bind_text(addStmt, 1, [select_Meal UTF8String], -1, SQLITE_TRANSIENT);         sqlite3_bind_text(addStmt, 2, [dateTime UTF8String], -1, SQLITE_TRANSIENT);         sqlite3_bind_text(addStmt, 3, [location UTF8String], -1, SQLITE_TRANSIENT);         sqlite3_bind_text(addStmt, 4, [mealItem UTF8String], -1, SQLITE_TRANSIENT);          if(SQLITE_DONE != sqlite3_step(addStmt))             NSAssert1(0, @"Error while inserting data. '%s'", sqlite3_errmsg(database));         //else             //SQLite provides a method to get the last primary key inserted by using sqlite3_last_insert_rowid             //coffeeID = sqlite3_last_insert_rowid(database);          //Reset the add statement.         sqlite3_reset(addStmt);      }     else         sqlite3_close(database);   } 

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