diff --git a/Cargo.lock b/Cargo.lock
index bec683e..ad572d1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -36,18 +36,18 @@ dependencies = [
 
 [[package]]
 name = "ansi_term"
-version = "0.11.0"
+version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
+checksum = "d52a9bb7ec0cf484c551830a7ce27bd20d67eac647e1befb56b0be4ee39a55d2"
 dependencies = [
  "winapi",
 ]
 
 [[package]]
 name = "anyhow"
-version = "1.0.48"
+version = "1.0.51"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "62e1f47f7dc0422027a4e370dd4548d4d66b26782e513e98dca1e689e058a80e"
+checksum = "8b26702f315f53b6071259e15dd9d64528213b44d61de1ec926eca7715d62203"
 
 [[package]]
 name = "ascii"
@@ -71,9 +71,9 @@ dependencies = [
 
 [[package]]
 name = "async-trait"
-version = "0.1.51"
+version = "0.1.52"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "44318e776df68115a881de9a8fd1b9e53368d7a4a5ce4cc48517da3393233a5e"
+checksum = "061a7acccaa286c011ddc30970520b98fa40e00c9d644633fb26b5fc63a265e3"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -220,9 +220,9 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "2.33.3"
+version = "2.34.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "37e58ac78573c40708d45522f0d80fa2f01cc4f9b4e2bf749807255454312002"
+checksum = "a0610544180c38b88101fecf2dd634b174a62eef6946f84dfc6a7127512b381c"
 dependencies = [
  "ansi_term",
  "atty",
@@ -289,9 +289,9 @@ checksum = "ccaeedb56da03b09f598226e25e80088cb4cd25f316e6e4df7d695f0feeb1403"
 
 [[package]]
 name = "crc32fast"
-version = "1.2.2"
+version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3825b1e8580894917dc4468cb634a1b4e9745fddc854edad72d9c04644c0319f"
+checksum = "738c290dfaea84fc1ca15ad9c168d083b05a714e1efddd8edaab678dc28d2836"
 dependencies = [
  "cfg-if",
 ]
@@ -559,9 +559,9 @@ dependencies = [
 
 [[package]]
 name = "h2"
-version = "0.3.7"
+version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7fd819562fcebdac5afc5c113c3ec36f902840b70fd4fc458799c8ce4607ae55"
+checksum = "8f072413d126e57991455e0a922b31e4c8ba7c2ffbebf6b78b4f8521397d65cd"
 dependencies = [
  "bytes",
  "fnv",
@@ -679,9 +679,9 @@ checksum = "c4a1e36c821dbe04574f602848a19f742f4fb3c98d40449f11bcad18d6b17421"
 
 [[package]]
 name = "hyper"
-version = "0.14.15"
+version = "0.14.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "436ec0091e4f20e655156a30a0df3770fe2900aa301e548e08446ec794b6953c"
+checksum = "b7ec3e62bdc98a2f0393a5048e4c30ef659440ea6e0e572965103e72bd836f55"
 dependencies = [
  "bytes",
  "futures-channel",
@@ -734,9 +734,9 @@ dependencies = [
 
 [[package]]
 name = "itertools"
-version = "0.10.1"
+version = "0.10.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "69ddb889f9d0d08a67338271fa9b62996bc788c7796a5c18cf057420aaed5eaf"
+checksum = "a9a9d19fa1e79b6215ff29b9d6880b706147f16e9b1dbb1e4e5947b5b02bc5e3"
 dependencies = [
  "either",
 ]
@@ -814,9 +814,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.108"
+version = "0.2.110"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8521a1b57e76b1ec69af7599e75e38e7b7fad6610f037db8c79b127201b5d119"
+checksum = "b58a4469763e4e3a906c4ed786e1c70512d16aa88f84dded826da42640fc6a1c"
 
 [[package]]
 name = "libsqlite3-sys"
@@ -1130,9 +1130,9 @@ checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
 
 [[package]]
 name = "pkg-config"
-version = "0.3.22"
+version = "0.3.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "12295df4f294471248581bc09bef3c38a5e46f1e36d6a37353621a0c6c357e1f"
+checksum = "d1a3ea4f0dd7f1f3e512cf97bf100819aa547f36a6eccac8dbaae839eb92363e"
 
 [[package]]
 name = "ppv-lite86"
@@ -1166,9 +1166,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.32"
+version = "1.0.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ba508cc11742c0dc5c1659771673afbab7a0efab23aa17e854cbab0837ed0b43"
+checksum = "fb37d2df5df740e582f28f8560cf425f52bb267d872fe58358eadb554909f07a"
 dependencies = [
  "unicode-xid",
 ]
@@ -1317,9 +1317,9 @@ dependencies = [
 
 [[package]]
 name = "ryu"
-version = "1.0.5"
+version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
+checksum = "3c9613b5a66ab9ba26415184cfc41156594925a9cf3a2057e57f31ff145f6568"
 
 [[package]]
 name = "safemem"
@@ -1384,18 +1384,18 @@ dependencies = [
 
 [[package]]
 name = "serde"
-version = "1.0.130"
+version = "1.0.131"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f12d06de37cf59146fbdecab66aa99f9fe4f78722e3607577a5375d66bd0c913"
+checksum = "b4ad69dfbd3e45369132cc64e6748c2d65cdfb001a2b1c232d128b4ad60561c1"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.130"
+version = "1.0.131"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d7bc1a1ab1961464eae040d96713baa5a724a8152c1222492465b54322ec508b"
+checksum = "b710a83c4e0dff6a3d511946b95274ad9ca9e5d3ae497b63fda866ac955358d2"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/src/sqlite/chat_index.sql b/src/sqlite/chat_index.sql
index 21e48b0..dc3892d 100644
--- a/src/sqlite/chat_index.sql
+++ b/src/sqlite/chat_index.sql
@@ -1,6 +1,6 @@
 -- chat index table
 CREATE TABLE IF NOT EXISTS chat_index (
-    id TEXT NOT NULL,
+    id TEXT NOT NULL UNIQUE,
     is_group_chat BOOLEAN DEFAULT 0 NOT NULL CHECK (is_group_chat IN (0, 1)),
     title TEXT NOT NULL,
     description TEXT,
diff --git a/src/sqlite/msgdata_template.sql b/src/sqlite/msgdata_template.sql
index 486926b..89f8566 100644
--- a/src/sqlite/msgdata_template.sql
+++ b/src/sqlite/msgdata_template.sql
@@ -1,7 +1,7 @@
 -- msgdata_template definition
 -- TODO Add IF NOT EXISTS to prevent panics
 CREATE TABLE msgdata_{chat_id} (
-	msg_id TEXT NOT NULL,
+	msg_id TEXT NOT NULL UNIQUE,
 	timestamp INTEGER NOT NULL,
 	sender_id TEXT NOT NULL,
 	msg_type INTEGER NOT NULL,
diff --git a/src/sqlite/users.sql b/src/sqlite/users.sql
index 9b4e4f3..e11c4d4 100644
--- a/src/sqlite/users.sql
+++ b/src/sqlite/users.sql
@@ -2,7 +2,7 @@
 
 CREATE TABLE IF NOT EXISTS users (
 	id TEXT NOT NULL PRIMARY KEY,
-	user_name TEXT NOT NULL,
+	user_name TEXT NOT NULL UNIQUE,
 	display_name TEXT,
 	activated BOOLEAN DEFAULT 0 NOT NULL CHECK (activated IN (0, 1)),
 	created INTEGER NOT NULL,