diff --git a/stdlib/docTable.as b/stdlib/docTable.as
index a8234c01f98..f70e9182658 100644
--- a/stdlib/docTable.as
+++ b/stdlib/docTable.as
@@ -210,6 +210,23 @@ class DocTable<Id,Doc,Info>(
     }
   };
 
+  /**
+   `upsertInfo`
+   ---------
+
+   Updates the document with the given id, or inserts a new document if nothing exists. Returns the old document if it was replaced.
+
+   */
+  upsertInfo(id:Id, info:Info) : ?Doc {
+    let doc = docOfInfo(info);
+    switch doc {
+      case null { null };
+      case (?doc) {
+        updateDoc(id, doc)
+      }
+    }
+  };
+
   /**
    `rem`
    ---------
diff --git a/stdlib/examples/produce-exchange/serverActor.as b/stdlib/examples/produce-exchange/serverActor.as
index d36688ffe9d..eeafde7f29e 100644
--- a/stdlib/examples/produce-exchange/serverActor.as
+++ b/stdlib/examples/produce-exchange/serverActor.as
@@ -54,6 +54,7 @@ actor server = {
  */
 
   registrarAddUser(
+    userId: UserId,
     short_name_: Text,
     description_: Text,
     region_: RegionId,
@@ -63,51 +64,56 @@ actor server = {
     isTransporter: Bool
   ) : async ?UserId {
 
-    let prId = if isProducer { getModel().producerTable.addInfoGetId(
-      func(id_:ProducerId):ProducerInfo {
+    let producer_ = if isProducer {
+      getModel().producerTable.upsertInfo(userId,
         shared {
-          id=id_:ProducerId;
+          id=userId:ProducerId;
           short_name=short_name_;
           description=description_;
           region=region_;
           inventory=[];
           reserved=[];
         }
-      }) } else null;
+      )
+    } else null;
 
-    let trId = if isTransporter { getModel().transporterTable.addInfoGetId(
-      func(id_:TransporterId):TransporterInfo {
+    let transporter_ = if isTransporter {
+      getModel().transporterTable.upsertInfo(userId,
         shared {
-          id=id_:TransporterId;
+          id=userId:TransporterId;
           short_name=short_name_;
           description=description_;
           routes=[];
           reserved=[];
         }
-      }) } else null;
+      )
+    } else null;
 
-    let rrId = if isRetailer { getModel().retailerTable.addInfoGetId(
-      func(id_:RetailerId):RetailerInfo {
+    let retailer_ = if isRetailer {
+      getModel().retailerTable.upsertInfo(userId,
         shared {
-          id=id_;
+          id=userId;
           short_name=short_name_;
           description=description_;
           region=region_:RegionId
         }
-      }) } else null;
+      )
+    } else null;
 
-    getModel().userTable.addInfoGetId(
-      func (id_: UserId) : UserInfo =
-        shared {
-          id = id_;
-          short_name = short_name_;
-          description = description_;
-          region = region_;
-          producerId = prId;
-          transporterId = trId;
-          retailerId = rrId;
-          isDeveloper = isDeveloper_;
-        })
+    let user_ = getModel().userTable.upsertInfo(userId,
+      shared {
+        id = userId;
+        short_name = short_name_;
+        description = description_;
+        region = region_;
+        producerId = ?userId;
+        transporterId = ?userId;
+        retailerId = ?userId;
+        isDeveloper = isDeveloper_;
+      }
+    );
+
+    ?userId
   };
 
   /**
@@ -338,21 +344,22 @@ actor server = {
    */
 
   registrarAddProducer(
+    producerId: ProducerId,
     short_name_:  Text,
     description_: Text,
     region_: RegionId,
   ) : async ?ProducerId {
-    getModel().producerTable.addInfoGetId(
-      func(id_:ProducerId):ProducerInfo {
-        shared {
-          id=id_:ProducerId;
-          short_name=short_name_:Text;
-          description=description_:Text;
-          region=region_:RegionId;
-          inventory=[];
-          reserved=[];
-        }
-      })
+    let producer_ = getModel().producerTable.upsertInfo(producerId,
+      shared {
+        id=producerId:ProducerId;
+        short_name=short_name_;
+        description=description_;
+        region=region_;
+        inventory=[];
+        reserved=[];
+      });
+
+    ?producerId
   };
 
   /**
@@ -405,19 +412,20 @@ actor server = {
    */
 
   registrarAddRetailer(
+    retailerId:   RetailerId,
     short_name_:  Text,
     description_: Text,
     region_: RegionId,
   ) : async ?RetailerId {
-    getModel().retailerTable.addInfoGetId(
-      func(id_:RetailerId):RetailerInfo {
-        shared {
-          id=id_:RetailerId;
-          short_name=short_name_:Text;
-          description=description_:Text;
-          region=region_:RegionId
-        }
-      })
+    let retailer_ = getModel().retailerTable.upsertInfo(retailerId,
+      shared {
+        id=retailerId:RetailerId;
+        short_name=short_name_:Text;
+        description=description_:Text;
+        region=region_:RegionId
+      });
+
+    ?retailerId
   };
 
   /**
@@ -466,20 +474,20 @@ actor server = {
 
    */
   registrarAddTransporter(
+    transporterId: TransporterId,
     short_name_:  Text,
     description_: Text,
   ) : async ?TransporterId {
-    getModel().transporterTable.addInfoGetId(
-      func(id_:TransporterId):TransporterInfo {
-        shared {
-          id=id_:TransporterId;
-          short_name=short_name_:Text;
-          description=description_:Text;
-          routes=[];
-          reserved=[];
-        }
-      })
-
+    let transporter_ = getModel().transporterTable.upsertInfo(transporterId,
+      shared {
+        id=transporterId:TransporterId;
+        short_name=short_name_:Text;
+        description=description_:Text;
+        routes=[];
+        reserved=[];
+      });
+
+    ?transporterId
   };
 
   /**
diff --git a/stdlib/examples/produce-exchange/serverModel.as b/stdlib/examples/produce-exchange/serverModel.as
index 2e86bda2381..45d1c6b7237 100644
--- a/stdlib/examples/produce-exchange/serverModel.as
+++ b/stdlib/examples/produce-exchange/serverModel.as
@@ -47,16 +47,24 @@ class Model() {
 
   private idIsEq(x:Nat,y:Nat):Bool { x == y };
 
+  private userIdIsEq(x:UserId,y:UserId):Bool { x == y };
+
   private idPairIsEq(x:(Nat,Nat),y:(Nat,Nat)):Bool { x.0 == y.0 and x.1 == y.1 };
 
   private idHash(x:Nat):Hash { Hash.hashOfInt(x) };
 
+  private userIdHash(x:UserId):Hash { Hash.hashOfText(x) };
+
   private idPairHash(x:(Nat,Nat)):Hash { Hash.hashOfIntAcc(Hash.hashOfInt(x.0), x.1) };
 
   private keyOf(x:Nat):Key<Nat> {
     new { key = x ; hash = idHash(x) }
   };
 
+  private keyOfUserId(x:UserId):Key<UserId> {
+    new { key = x ; hash = userIdHash(x) }
+  };
+
   private keyOfIdPair(x:Nat, y:Nat):Key<(Nat,Nat)> {
     new { key = (x,y) ; hash = idPairHash(x,y) }
   };
@@ -118,10 +126,10 @@ secondary maps.
 
   var userTable : UserTable =
     DocTable<UserId, UserDoc, UserInfo>(
-    0,
-    func(x:UserId):UserId{x+1},
+    "",
+    func(x:UserId):UserId{x},
     func(x:UserId,y:UserId):Bool{x==y},
-    idHash,
+    userIdHash,
     func(doc:UserDoc):UserInfo = shared {
       id=doc.id;
       short_name=doc.short_name;
@@ -229,10 +237,10 @@ secondary maps.
 
   var producerTable : ProducerTable =
     DocTable<ProducerId, ProducerDoc, ProducerInfo>(
-    0,
-    func(x:ProducerId):ProducerId{x+1},
+    "",
+    func(x:ProducerId):ProducerId{x},
     func(x:ProducerId,y:ProducerId):Bool{x==y},
-    idHash,
+    userIdHash,
     func(doc:ProducerDoc):ProducerInfo = shared {
       id=doc.id;
       short_name=doc.short_name;
@@ -313,10 +321,10 @@ secondary maps.
 
   var transporterTable : TransporterTable =
     DocTable<TransporterId, TransporterDoc, TransporterInfo> (
-      0,
-      func(x:TransporterId):TransporterId{x+1},
+      "",
+      func(x:TransporterId):TransporterId{x},
       func(x:TransporterId,y:TransporterId):Bool{x==y},
-      idHash,
+      userIdHash,
       func(doc:TransporterDoc):TransporterInfo = shared {
         id=doc.id;
         short_name=doc.short_name;
@@ -341,10 +349,10 @@ secondary maps.
 
   var retailerTable : RetailerTable =
     DocTable<RetailerId, RetailerDoc, RetailerInfo>(
-      0,
-      func(x:RetailerId):RetailerId{x+1},
+      "",
+      func(x:RetailerId):RetailerId{x},
       func(x:RetailerId,y:RetailerId):Bool{x==y},
-      idHash,
+      userIdHash,
       func(doc:RetailerDoc):RetailerInfo = shared {
         id=doc.id;
         short_name=doc.short_name;
@@ -706,7 +714,7 @@ than the MVP goals, however.
     Map.insert2D<RegionId, ProducerId, InventoryMap>(
       inventoryByRegion,
       keyOf(producer_.region.id), idIsEq,
-      keyOf(producer_.id), idIsEq,
+      keyOfUserId(producer_.id), userIdIsEq,
       updatedInventory,
     );
 
@@ -817,7 +825,7 @@ than the MVP goals, however.
       let (t, d) = Trie.remove3D<RegionId, ProducerId, InventoryId, InventoryDoc>(
         inventoryByRegion,
         keyOf(producer.region.id), idIsEq,
-        keyOf(producer.id), idIsEq,
+        keyOfUserId(producer.id), userIdIsEq,
         keyOf(id), idIsEq
       );
       assertSome<InventoryDoc>(d);
@@ -951,7 +959,7 @@ than the MVP goals, however.
    `transporterAllRouteInfo`
    ---------------------------
    */
-  transporterAllRouteInfo(id:RouteId) : ?[RouteInfo] {
+  transporterAllRouteInfo(id:TransporterId) : ?[RouteInfo] {
     let doc = switch (transporterTable.getDoc(id)) {
       case null { return null };
       case (?doc) { doc };
@@ -1087,7 +1095,7 @@ than the MVP goals, however.
     retailerQueryCount += 1;
 
     debug "\nRetailer ";
-    debugInt id;
+    debug id;
     debug " sends `retailerQueryAll`\n";
     debug "------------------------------------\n";
 
@@ -1136,7 +1144,7 @@ than the MVP goals, however.
           routes,
           /** - (To perform this Cartesian product, use a 1D inventory map:) */
           Trie.mergeDisjoint2D<ProducerId, InventoryId, InventoryDoc>(
-            inventory, idIsEq, idIsEq),
+            inventory, userIdIsEq, idIsEq),
 
           func (route_id:RouteId,
                 route   :RouteDoc,
diff --git a/stdlib/examples/produce-exchange/serverTypes.as b/stdlib/examples/produce-exchange/serverTypes.as
index 19a07c15dff..9f46dff0a9e 100644
--- a/stdlib/examples/produce-exchange/serverTypes.as
+++ b/stdlib/examples/produce-exchange/serverTypes.as
@@ -49,17 +49,18 @@ Externally, these Ids give a unique identifier that is unique to its type, but n
 Internally, each type of Id serves as a "row key" for a table (or two).
 
 */
-type UserId        = Nat;
+type Id            = Text;
+type UserId        = Id;
 
 type RegionId      = Nat;
 type TruckTypeId   = Nat;
 type ProduceId     = Nat;
 
-type ProducerId    = Nat;
+type ProducerId    = Id;
 type InventoryId   = Nat;
 type ReservedInventoryId = Nat;
-type RetailerId    = Nat;
-type TransporterId = Nat;
+type RetailerId    = Id;
+type TransporterId = Id;
 type RouteId       = Nat;
 type ReservedRouteId = Nat;
 
diff --git a/stdlib/examples/produce-exchange/test/simpleSetupAndQuery.as b/stdlib/examples/produce-exchange/test/simpleSetupAndQuery.as
index c0e6ecc4e36..429e9001340 100644
--- a/stdlib/examples/produce-exchange/test/simpleSetupAndQuery.as
+++ b/stdlib/examples/produce-exchange/test/simpleSetupAndQuery.as
@@ -64,29 +64,29 @@ actor class Test() = this {
       printEntityCount("Produce", (await s.getCounts()).produce_count);
 
       // populate with producers
-      let pra = await s.registrarAddProducer("pra", "", unwrap<RegionId>(rega) );
-      let prb = await s.registrarAddProducer("prb", "", unwrap<RegionId>(rega) );
-      let prc = await s.registrarAddProducer("prc", "", unwrap<RegionId>(regb) );
-      let prd = await s.registrarAddProducer("prd", "", unwrap<RegionId>(rega) );
-      let pre = await s.registrarAddProducer("pre", "", unwrap<RegionId>(regb) );
+      let pra = await s.registrarAddProducer("pra", "Producer A", "", unwrap<RegionId>(rega) );
+      let prb = await s.registrarAddProducer("prb", "Producer B", "", unwrap<RegionId>(rega) );
+      let prc = await s.registrarAddProducer("prc", "Producer C", "", unwrap<RegionId>(regb) );
+      let prd = await s.registrarAddProducer("prd", "Producer D", "", unwrap<RegionId>(rega) );
+      let pre = await s.registrarAddProducer("pre", "Producer E", "", unwrap<RegionId>(regb) );
 
       printEntityCount("Producer", (await s.getCounts()).producer_count);
 
       // populate with transporters
-      let tra = await s.registrarAddTransporter("tra", "" );
-      let trb = await s.registrarAddTransporter("trb", "" );
-      let trc = await s.registrarAddTransporter("trc", "" );
-      let trd = await s.registrarAddTransporter("trd", "" );
-      let tre = await s.registrarAddTransporter("tre", "" );
+      let tra = await s.registrarAddTransporter("tra", "Transporter A", "" );
+      let trb = await s.registrarAddTransporter("trb", "Transporter B", "" );
+      let trc = await s.registrarAddTransporter("trc", "Transporter C", "" );
+      let trd = await s.registrarAddTransporter("trd", "Transporter D", "" );
+      let tre = await s.registrarAddTransporter("tre", "Transporter E", "" );
 
       printEntityCount("Transporter", (await s.getCounts()).transporter_count);
 
       // populate with retailers
-      let rra = await s.registrarAddRetailer("rra", "", unwrap<RegionId>(regc) );
-      let rrb = await s.registrarAddRetailer("rrb", "", unwrap<RegionId>(regd) );
-      let rrc = await s.registrarAddRetailer("rrc", "", unwrap<RegionId>(rege) );
-      let rrd = await s.registrarAddRetailer("rrd", "", unwrap<RegionId>(regc) );
-      let rre = await s.registrarAddRetailer("rre", "", unwrap<RegionId>(rege) );
+      let rra = await s.registrarAddRetailer("rra", "Retailer A", "", unwrap<RegionId>(regc) );
+      let rrb = await s.registrarAddRetailer("rrb", "Retailer B", "", unwrap<RegionId>(regd) );
+      let rrc = await s.registrarAddRetailer("rrc", "Retailer C", "", unwrap<RegionId>(rege) );
+      let rrd = await s.registrarAddRetailer("rrd", "Retailer D", "", unwrap<RegionId>(regc) );
+      let rre = await s.registrarAddRetailer("rre", "Retailer E", "", unwrap<RegionId>(rege) );
 
       printEntityCount("Retailer", (await s.getCounts()).retailer_count);
 
diff --git a/stdlib/hash.as b/stdlib/hash.as
index 4814bb8a3f3..ad22bab7cc7 100644
--- a/stdlib/hash.as
+++ b/stdlib/hash.as
@@ -70,6 +70,14 @@ let BitVec = new {
     ha == hb
   };
 
+  func hashOfText(t:Text) : BitVec {
+    var x = 0 : Word32;
+    for (c in t.chars()) {
+      x := x ^ charToWord32(c);
+    };
+    return x
+  };
+
   func bitsPrintRev(bits:BitVec) {
     for (j in range(0, length() - 1)) {
       if (getHashBit(bits, j)) {
@@ -89,7 +97,7 @@ let BitVec = new {
       }
     }
   };
-  
+
   func toList(v:BitVec) : BitList {
     func rec(pos:Nat) : BitList {
       if (pos >= length()) { null }
@@ -171,12 +179,12 @@ let BitList = new {
 };
 
 
-/** 
+/**
  Canonical representations
  ---------------------------
 
  Choose a canonical representation of hash values for the rest of
- the standard library to use: 
+ the standard library to use:
 */
 
 type Hash = BitVec;