diff --git a/bookshop/test/dynamic-constraints/server.js b/bookshop/test/dynamic-constraints/server.js
index d7d62fbb..9c230857 100644
--- a/bookshop/test/dynamic-constraints/server.js
+++ b/bookshop/test/dynamic-constraints/server.js
@@ -3,41 +3,14 @@
 // using db-level constraints.
 //
 
-const cds = require('@sap/cds')
+const cds = require('@sap/cds'); require('./validate.js')
 cds.on('served', ()=> {
-
-  const $ = cds.validate
-  cds.validate = function (entity, key, ...columns) {
-
-    if (entity?.ref) entity = { // quick and dirty
-      name: entity.ref[0],
-      constraints: { // even quicker and dirtier
-        name: entity.ref[0] +'.constraints',
-        keys: {ID:1}
-      }
-    }
-    else if (!entity.is_entity) return // we skip all standard validations for the experiments
-    else if (!entity.is_entity) return $(...arguments) // eslint-disable-line no-dupe-else-if
-
-    if (entity.constraints) entity = entity.constraints
-    if (!key) return key => cds.validate(entity,key)
-    if (key.results) key = key.results[0].lastInsertRowid // quick and dirty
-    if (key.ID) key = key.ID // quick and dirty
-
-    return SELECT.one.from (entity, key, columns.length && columns) .then (checks => {
-      const failed = {}; for (let c in checks) {
-        if (c in entity.keys) continue
-        if (c[0] == '_') continue
-        if (checks[c]) failed[c] = checks[c]
-      }
-      if (Object.keys(failed).length) throw cds.error `Invalid input: ${failed}`
-    })
-  }
-
   const { AdminService } = cds.services
   AdminService.after (['CREATE','UPDATE'], (result,req) =>  cds.validate (req.subject, result))
 })
 
+
+
 Object.defineProperties (cds.entity.prototype, {
   constraints: { get() { return cds.model.definitions[this.name+'.constraints'] }},
   fields: { get() { return cds.model.definitions[this.name+'.field.control'] }},
diff --git a/bookshop/test/dynamic-constraints/srv/validation.cds b/bookshop/test/dynamic-constraints/srv/validation.cds
index a845caf7..4d733947 100644
--- a/bookshop/test/dynamic-constraints/srv/validation.cds
+++ b/bookshop/test/dynamic-constraints/srv/validation.cds
@@ -68,7 +68,7 @@ extend service AdminService with {
     null as name,
 
     // constraint related to two fields
-    dateOfDeath > dateOfBirth ? 'we must be born before we die' : null as _born_before_death,
+    dateOfDeath < dateOfBirth ? 'we can''t die before we are born' : null as _born_before_death,
     $self._born_before_death as dateOfBirth,
     $self._born_before_death as dateOfDeath,
 
diff --git a/bookshop/test/dynamic-constraints/validate.js b/bookshop/test/dynamic-constraints/validate.js
new file mode 100644
index 00000000..8a93f111
--- /dev/null
+++ b/bookshop/test/dynamic-constraints/validate.js
@@ -0,0 +1,33 @@
+const cds = require('@sap/cds')
+const $super = { validate: cds.validate, skip(){} }
+
+
+/**
+ * Quick and dirty implementation for cds.validate() using db-level constraints.
+ */
+cds.validate = function (x, pk, ...columns) {
+
+  // Delegate to base impl of cds.validate() for standard input validation
+  if (!_is_constraints(x)) return $super.skip (...arguments)
+
+  // Support subject refs to base entities as arguments
+  if (x?.ref) [ x, pk ] = [ x.ref +'.constraints', pk.ID||pk ]
+
+  // Run the constraints check query
+  const constraints = cds.model.definitions[x] || cds.error `No such constraints view: ${x}`
+  return SELECT.one.from (constraints, pk, columns.length && columns)
+
+  // Collect and throw errors, if any
+  .then (checks => {
+    const failed = {}; for (let c in checks) {
+      if (c in constraints.keys) continue
+      if (c[0] == '_') continue
+      if (checks[c]) failed[c] = checks[c]
+    }
+    if (Object.keys(failed).length) throw cds.error `Invalid input: ${failed}`
+  })
+}
+
+
+// Helpers
+const _is_constraints = x => x.ref || x.is_entity || typeof x === 'string'