Database is locked sqlite ios

I write a application have use sqlite save data. I add data to table success. But i can't delete content in table. It notify DATABASE IS LOCKED.

My code:

Code Delete in sqlite

//Xoá tài khoản
-(BOOL) delete_Account
{
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &database) == SQLITE_OK)
{
    const char *delete_Statement = "DELETE FROM info";
    if(sqlite3_prepare_v2(database, delete_Statement,-1, &statement, NULL)==SQLITE_OK)
    {
        if (sqlite3_step(statement) == SQLITE_DONE)
        {
            NSLog(@"DELETE Account : %@", @"Ban da xoa thanh cong!");
            return YES;
        }
        else{
            NSLog(@"DELETE Account: %@ %s",@"Xoa that bai",sqlite3_errmsg(database));
        }
    }
    sqlite3_finalize(statement);
}
    sqlite3_close(database);
return NO;
}

Full code

#import "DBManager.h"
static DBManager *sharedInstance = nil;
static sqlite3 *database = nil;
static sqlite3_stmt *statement = nil;

@implementation DBManager

+(DBManager*)getSharedInstance{
if (!sharedInstance) {
    sharedInstance = [[super allocWithZone:NULL]init];
    [sharedInstance createDB];
}
return sharedInstance;
}

-(BOOL)createDB{
NSString *docsDir;
NSArray *dirPaths;
// Get the documents directory
dirPaths = NSSearchPathForDirectoriesInDomains
(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = dirPaths[0];
// Build the path to the database file
databasePath = [[NSString alloc] initWithString:
                [docsDir stringByAppendingPathComponent: @"Sync.db"]];
BOOL isSuccess = YES;
NSFileManager *filemgr = [NSFileManager defaultManager];
if ([filemgr fileExistsAtPath: databasePath ] == NO)
{
    const char *dbpath = [databasePath UTF8String];
    if (sqlite3_open(dbpath, &database) == SQLITE_OK)
    {
        char *errMsg;
        const char *sql_statement = "CREATE TABLE IF NOT EXISTS info (ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME TEXT, PASS TEXT, TOKEN TEXT, COMPANY TEXT, CUSTOMER TEXT)";
        const char*sql_create_contact_db = "CREATE TABLE IF NOT EXISTS contact (ID INTEGER PRIMARY KEY AUTOINCREMENT, FIRST TEXT, LAST TEXT, PHONE TEXT, EMAIL TEXT)";
        if (sqlite3_exec(database, sql_statement, NULL, NULL, &errMsg)
            != SQLITE_OK)
        {
            isSuccess = NO;
            NSLog(@"Failed to create table INFO");
        }
        if (sqlite3_exec(database, sql_create_contact_db, NULL, NULL, &errMsg)
            != SQLITE_OK)
        {
            isSuccess = NO;
            NSLog(@"Failed to create table CONTACT");
        }
        sqlite3_finalize(statement);
        sqlite3_close(database);
        return  isSuccess;
    }
    else {
        isSuccess = NO;
        NSLog(@"Failed to open/create database");
    }
}
return isSuccess;
}

-(BOOL) add_Data_Info:(NSString *)username :(NSString *)password :(NSString *)token
{
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &database) == SQLITE_OK)
{
    NSString *insertSQL = [NSString stringWithFormat:@"INSERT INTO info (name, pass, token, company, customer) VALUES (\"%@\",\"%@\",\"%@\",\"%@\",\"%@\")", username, password, token, @"ON", @"OFF"];
    const char *insert_Statement = [insertSQL UTF8String];
    sqlite3_prepare_v2(database, insert_Statement,-1, &statement, NULL);
    if (sqlite3_step(statement) == SQLITE_DONE)
    {
        return YES;
    }
    else {
        return NO;
    }
    sqlite3_finalize(statement);
}
sqlite3_close(database);
return NO;
 }

//Thêm data vào database
-(BOOL) add_Data_Sync:(NSString *)first :(NSString *)last :(NSString *)phone : (NSString*)email
{
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &database) == SQLITE_OK)
{
    NSString *insertSQL = [NSString stringWithFormat:@"INSERT INTO contact (first,last,phone,email) VALUES (\"%@\",\"%@\",\"%@\",\"%@\")", first, last, phone, email];
    const char *insert_Statement = [insertSQL UTF8String];
    sqlite3_prepare_v2(database, insert_Statement,-1, &statement, NULL);
    if (sqlite3_step(statement) == SQLITE_DONE)
    {
        return YES;
    }
    else {
        return NO;
    }
    sqlite3_finalize(statement);
}
    sqlite3_close(database);
return NO;
}

//Cập nhật token
-(BOOL) update_Data_Info:(NSString *)username : (NSString *) token
{
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &database) == SQLITE_OK)
{
    NSString *updateSQL = [NSString stringWithFormat:@"UPDATE info Set token = \"%@\"where name = \"\"%@\")", token, username];
    const char *update_Statement = [updateSQL UTF8String];
    sqlite3_prepare_v2(database, update_Statement,-1, &statement, NULL);
    if (sqlite3_step(statement) == SQLITE_DONE)
    {
        return YES;
    }
    else {
        return NO;
    }
    sqlite3_finalize(statement);
}
    sqlite3_close(database);
return NO;
}

//Cập nhật token
-(BOOL) update_Sw_Info:(NSString *)username : (NSString *) status
{
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &database) == SQLITE_OK)
{
    NSString *updateSQL = [NSString stringWithFormat:@"UPDATE info Set company = \"%@\" where name = \"%@\" ", status, username];
    const char *update_Statement = [updateSQL UTF8String];
    sqlite3_prepare_v2(database, update_Statement,-1, &statement, NULL);
    if (sqlite3_step(statement) == SQLITE_DONE)
    {
        return YES;
    }
    else {
        return NO;
    }
    sqlite3_finalize(statement);
}
    sqlite3_close(database);
return NO;
}

//Xoá tài khoản
-(BOOL) delete_Account
{
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &database) == SQLITE_OK)
{
    const char *delete_Statement = "DELETE FROM info";
    if(sqlite3_prepare_v2(database, delete_Statement,-1, &statement, NULL)==SQLITE_OK)
    {
        if (sqlite3_step(statement) == SQLITE_DONE)
        {
            NSLog(@"DELETE Account : %@", @"Ban da xoa thanh cong!");
            return YES;
        }
        else{
            NSLog(@"DELETE Account: %@ %s",@"Xoa that bai",sqlite3_errmsg(database));
        }
    }
    sqlite3_finalize(statement);
}
    sqlite3_close(database);
return NO;
}

-(BOOL)delete_All_Contact
{
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &database) == SQLITE_OK)
{
    NSString *deleteSQL = [NSString stringWithFormat:@"DELETE FROM contact"];
    const char *delete_Statement = [deleteSQL UTF8String];
    sqlite3_prepare_v2(database, delete_Statement,-1, &statement, NULL);
    if (sqlite3_step(statement) == SQLITE_ROW)
    {
        return YES;
    }
    else {
        return NO;
    }
    sqlite3_finalize(statement);
}
    sqlite3_close(database);
return NO;

}

- (NSArray*) getInfo
{
        const char *dbpath = [databasePath UTF8String];
        if (sqlite3_open(dbpath, &database) == SQLITE_OK)
        {
            NSString *querySQL = [NSString stringWithFormat:
                                  @"SELECT name, token, pass, company, customer FROM info"];
            const char *query_stmt = [querySQL UTF8String];
            NSMutableArray *resultArray = [[NSMutableArray alloc]init];
            if (sqlite3_prepare_v2(database,
                                   query_stmt, -1, &statement, NULL) == SQLITE_OK)
            {
                if (sqlite3_step(statement) == SQLITE_ROW)
                {
                    NSString *name = [[NSString alloc] initWithUTF8String:
                                      (const char *) sqlite3_column_text(statement, 0)];
                    [resultArray addObject:name];
                    NSString *token = [[NSString alloc] initWithUTF8String:
                                            (const char *) sqlite3_column_text(statement, 1)];
                    [resultArray addObject:token];
                    NSString *pass = [[NSString alloc]initWithUTF8String:
                                      (const char *) sqlite3_column_text(statement, 2)];
                    [resultArray addObject:pass];
                    NSString *company = [[NSString alloc] initWithUTF8String:
                                       (const char *) sqlite3_column_text(statement, 3)];
                    [resultArray addObject:company];
                    NSString *customer = [[NSString alloc]initWithUTF8String:
                                      (const char *) sqlite3_column_text(statement, 4)];
                    [resultArray addObject:customer];
                    return resultArray;
                }
                else{
                    NSLog(@"Not found");
                    return nil;
                }
            }
            sqlite3_finalize(statement);
        }
    sqlite3_close(database);
        return nil;
}

//Kiểm tra dữ liệu trong database
-(int)checkContact : (NSString *) txtPhone
{
int check = 0;
const char *dbpath = [databasePath UTF8String];
if (sqlite3_open(dbpath, &database) == SQLITE_OK)
{
    NSString *querySQL = [NSString stringWithFormat:
                          @"SELECT COUNT(*) FROM contact WHERE phone = \"%@\"",txtPhone];
    const char *query_stmt = [querySQL UTF8String];
    NSMutableArray *resultArray = [[NSMutableArray alloc]init];
    if (sqlite3_prepare_v2(database,
                           query_stmt, -1, &statement, NULL) == SQLITE_OK)
    {
        if (sqlite3_step(statement) == SQLITE_ROW)
        {
            check = 1;
        }
    }
    sqlite3_finalize(statement);
}
    sqlite3_close(database);
return check;
}

@end