diff --git a/archunit/src/main/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlComponents.java b/archunit/src/main/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlComponents.java
index 1e920bd339..f9ddff7d5f 100644
--- a/archunit/src/main/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlComponents.java
+++ b/archunit/src/main/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlComponents.java
@@ -17,12 +17,14 @@
 
 import java.util.Collection;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.function.Predicate;
 
 import com.google.common.collect.FluentIterable;
 
 import static com.tngtech.archunit.library.plantuml.rules.PlantUmlComponent.Functions.TO_EXISTING_ALIAS;
+import static java.util.Objects.requireNonNull;
 import static java.util.function.Function.identity;
 import static java.util.stream.Collectors.toMap;
 
@@ -43,19 +45,16 @@ Collection<PlantUmlComponent> getComponentsWithAlias() {
         return componentsByAlias.values();
     }
 
-    PlantUmlComponent findComponentWith(String nameOrAlias) {
+    Optional<PlantUmlComponent> tryFindComponentWith(String nameOrAlias) {
         ComponentName componentName = new ComponentName(nameOrAlias);
         Alias alias = new Alias(nameOrAlias);
         PlantUmlComponent result = componentsByAlias.containsKey(alias) ? componentsByAlias.get(alias) : componentsByName.get(componentName);
-        if (result == null) {
-            throw new IllegalDiagramException("There is no Component with name or alias = '%s'. %s", nameOrAlias,
-                    "Components must be specified separately from dependencies.");
-        }
-        return result;
+        return Optional.ofNullable(result);
     }
 
     PlantUmlComponent findComponentWith(ComponentIdentifier identifier) {
-        return componentsByName.get(identifier.getComponentName());
+        return requireNonNull(componentsByName.get(identifier.getComponentName()),
+                () -> String.format("Unknown component '%s'", identifier.getComponentName()));
     }
 
     private static final Predicate<PlantUmlComponent> WITH_ALIAS = input -> input.getAlias().isPresent();
diff --git a/archunit/src/main/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlParser.java b/archunit/src/main/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlParser.java
index 420952ac41..14e6c34b2c 100644
--- a/archunit/src/main/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlParser.java
+++ b/archunit/src/main/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlParser.java
@@ -28,6 +28,8 @@
 import com.google.common.io.CharStreams;
 import com.tngtech.archunit.library.plantuml.rules.PlantUmlPatterns.PlantUmlComponentMatcher;
 import com.tngtech.archunit.library.plantuml.rules.PlantUmlPatterns.PlantUmlDependencyMatcher;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 import static java.nio.charset.StandardCharsets.UTF_8;
@@ -35,6 +37,8 @@
 import static java.util.stream.Collectors.toSet;
 
 class PlantUmlParser {
+    private static final Logger log = LoggerFactory.getLogger(PlantUmlParser.class);
+
     private final PlantUmlPatterns plantUmlPatterns = new PlantUmlPatterns();
 
     PlantUmlDiagram parse(URL url) {
@@ -78,9 +82,16 @@ private Set<PlantUmlComponent> parseComponents(List<String> plantUmlDiagramLines
     private ImmutableList<ParsedDependency> parseDependencies(PlantUmlComponents plantUmlComponents, List<String> plantUmlDiagramLines) {
         ImmutableList.Builder<ParsedDependency> result = ImmutableList.builder();
         for (PlantUmlDependencyMatcher matcher : plantUmlPatterns.matchDependencies(plantUmlDiagramLines)) {
-            PlantUmlComponent origin = findComponentMatching(plantUmlComponents, matcher.matchOrigin());
-            PlantUmlComponent target = findComponentMatching(plantUmlComponents, matcher.matchTarget());
-            result.add(new ParsedDependency(origin.getIdentifier(), target.getIdentifier()));
+            Optional<PlantUmlComponent> origin = tryFindComponentMatching(plantUmlComponents, matcher.matchOrigin());
+            Optional<PlantUmlComponent> target = tryFindComponentMatching(plantUmlComponents, matcher.matchTarget());
+            if (origin.isPresent() && target.isPresent()) {
+                result.add(new ParsedDependency(origin.get().getIdentifier(), target.get().getIdentifier()));
+            } else {
+                log.trace(
+                        "Ignoring dependency from {} to {}, because origin or target couldn't be parsed",
+                        matcher.matchOrigin(), matcher.matchTarget()
+                );
+            }
         }
         return result.build();
     }
@@ -113,11 +124,11 @@ private ImmutableSet<Stereotype> identifyStereotypes(PlantUmlComponentMatcher ma
         return result;
     }
 
-    private PlantUmlComponent findComponentMatching(PlantUmlComponents plantUmlComponents, String originOrTargetString) {
+    private Optional<PlantUmlComponent> tryFindComponentMatching(PlantUmlComponents plantUmlComponents, String originOrTargetString) {
         originOrTargetString = originOrTargetString.trim()
                 .replaceAll("^\\[", "")
                 .replaceAll("]$", "");
 
-        return plantUmlComponents.findComponentWith(originOrTargetString);
+        return plantUmlComponents.tryFindComponentWith(originOrTargetString);
     }
 }
diff --git a/archunit/src/test/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlParserTest.java b/archunit/src/test/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlParserTest.java
index 12a02d67b8..4ddcf9814e 100644
--- a/archunit/src/test/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlParserTest.java
+++ b/archunit/src/test/java/com/tngtech/archunit/library/plantuml/rules/PlantUmlParserTest.java
@@ -206,18 +206,6 @@ public void does_not_include_dependency_descriptions() {
                 .isEqualTo(new ComponentName("otherComponent"));
     }
 
-    @Test
-    public void throws_exception_with_components_that_are_not_yet_defined() {
-        File file = TestDiagram.in(temporaryFolder)
-                .dependencyFrom("[NotYetDefined]").to("[AlsoNotYetDefined]")
-                .write();
-
-        assertThatThrownBy(() -> createDiagram(file))
-                .isInstanceOf(IllegalDiagramException.class)
-                .hasMessageContaining("There is no Component with name or alias = 'NotYetDefined'")
-                .hasMessageContaining("Components must be specified separately from dependencies");
-    }
-
     @Test
     public void throws_exception_with_components_without_stereotypes() {
         File file = TestDiagram.in(temporaryFolder)
@@ -418,6 +406,37 @@ public void parses_a_component_diagram_that_uses_alias_with_and_without_brackets
         assertThat(bar.getDependencies()).isEmpty();
     }
 
+    @Test
+    public void ignores_components_that_are_not_yet_defined() {
+        File file = TestDiagram.in(temporaryFolder)
+                .dependencyFrom("[NotYetDefined]").to("[AlsoNotYetDefined]")
+                .write();
+
+        PlantUmlDiagram diagram = createDiagram(file);
+
+        assertThat(diagram.getComponentsWithAlias()).isEmpty();
+    }
+
+    @Test
+    public void ignores_database_components() {
+        File file = TestDiagram.in(temporaryFolder)
+                .rawLine("database \"DB\"")
+                .component("componentA").withAlias("aliasA").withStereoTypes("..packageA..")
+                .component("componentB").withAlias("aliasB").withStereoTypes("..packageB..")
+                .dependencyFrom("aliasA").to("aliasB")
+                .dependencyFrom("aliasB").to("DB")
+                .dependencyFrom("componentA").to("DB")
+                .write();
+
+        PlantUmlDiagram diagram = createDiagram(file);
+
+        PlantUmlComponent a = getComponentWithAlias(new Alias("aliasA"), diagram);
+        PlantUmlComponent b = getComponentWithAlias(new Alias("aliasB"), diagram);
+
+        assertThat(a.getDependencies()).containsOnly(b);
+        assertThat(b.getDependencies()).isEmpty();
+    }
+
     private PlantUmlComponent getComponentWithName(String componentName, PlantUmlDiagram diagram) {
         PlantUmlComponent component = diagram.getAllComponents().stream()
                 .filter(c -> c.getComponentName().asString().equals(componentName))