diff --git a/src/main.rs b/src/main.rs
index f4833bd..8a0c774 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,7 +5,7 @@ use std::mem::replace;
 use std::io::Read;
 use std::fs::read_to_string;
 use std::sync::RwLock;
-use std::collections::VecDeque;
+use std::collections::{HashMap, VecDeque};
 use chrono::offset::Utc;
 use reqwest::header::{IF_NONE_MATCH, IF_MODIFIED_SINCE, ETAG, LAST_MODIFIED, USER_AGENT};
 use diesel::{Connection, pg::PgConnection, prelude::*};
@@ -146,7 +146,7 @@ impl Resources {
 
                 let mut p = Parser::new();
                 let mut buf = [0; 1024];
-                let mut events = vec![];
+                let mut events = HashMap::new();
                 loop {
                     match res.read(&mut buf)? {
                         len if len > 0 => {
@@ -156,8 +156,8 @@ impl Resources {
                                 extract_vevent_objs(&mut objs, obj);
                                 for obj in objs {
                                     let dbg = format!("{:?}", obj);
-                                    if let Some(event) = obj_to_event(cal_opts.url.clone(), obj) {
-                                        events.push(event);
+                                    if let Some(event) = obj_to_event(cal_opts.url.clone(), &obj) {
+                                        events.insert(event.id.clone(), event);
                                     } else {
                                         println!("ignore {}", dbg);
                                     }
@@ -173,9 +173,9 @@ impl Resources {
                 diesel::delete(schema::events::dsl::events)
                     .filter(schema::events::dsl::calendar.eq(cal_opts.url))
                     .execute(&db)?;
-                for event in events {
+                for event in events.values() {
                     diesel::insert_into(schema::events::dsl::events)
-                        .values(&event)
+                        .values(event)
                         .execute(&db)?;
                 }