Question

我有一个sqlite数据库，我想进行更新。我使用这段代码：

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];

path = [documentsDirectory stringByAppendingPathComponent:@"memo.sqlite"];
const char *sqlStatement = "CREATE TABLE IF NOT EXISTS NOTES (title text PRIMARY KEY, category TEXT,content TEXT , dataAdd TEXT,deadline TEXT,place TEXT,photos TEXT);";

char *error;

//    path = [[NSBundle mainBundle] pathForResource:@"memo" ofType:@"sqlite"];

if (sqlite3_open([path UTF8String], &contactDB) == SQLITE_OK)
{
    NSLog(@"DB is open");
    if(sqlite3_exec(contactDB, sqlStatement, NULL, NULL, &error) == SQLITE_OK)
    {
        NSLog(@"All tables are created");      
    }
} 
else 
{
    NSLog(@"DB can't be open");
}

querySQL1 = @"select category from notes where id=8";
const char * query_stmt = [querySQL1 UTF8String];

sqlite3_prepare_v2(contactDB, query_stmt, -1, &statement, NULL);

NSString *updateSQL = [NSString stringWithFormat:
                       @"UPDATE notes set title=\"%@\" , content=\"%@\" WHERE title LIKE '\"%@\"'",self.titleNote.text,self.contentNote.text,self.titleNote.text];

const char *insert_stmt = [updateSQL UTF8String];
sqlite3_stmt *updateStmt = nil;

if(sqlite3_prepare_v2(contactDB, insert_stmt, -1, &statement, NULL) == SQLITE_OK)
{

    if (sqlite3_step(statement) == SQLITE_DONE)
    {
        NSLog(@"data updated");
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Your notes was updated."
                                                        message:@""
                                                       delegate:self
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
        [alert show];
        sqlite3_prepare_v2(contactDB, insert_stmt, -1, &statement, NULL);
        char* errmsg;
        sqlite3_exec(contactDB, "COMMIT", NULL, NULL, &errmsg);

        if(SQLITE_DONE != sqlite3_step(updateStmt)){
            NSLog(@"Error while updating. %s", sqlite3_errmsg(contactDB));
        }
    }
    else{
        NSLog(@"Error while creating update statement. '%s'", sqlite3_errmsg(contactDB));
    }
}
else
{ 
    NSLog(@"Error while creating update statement. '%s'", sqlite3_errmsg(contactDB));
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error to delete note."
                                                    message:@""
                                                   delegate:self
                                          cancelButtonTitle:@"Cancel"
                                          otherButtonTitles:nil];
    [alert show];
 }

但即使记录了“data updated”，也不会更新db。但是当我从db再次获得数据的结果相同时。

我错的时候有什么想法吗？

Answer 1

我认为sqlite3_step()返回SQLITE_DONE只意味着没有错误（即您的语句在语法上是正确的），而不是更新了一行。

您必须使用sqlite3_changes()来确定更新的行数。

更新sqlite数据库Objective-c

1 个答案: