diff --git a/pom.xml b/pom.xml
index ba7a7a9..5aaef21 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>jef</groupId>
     <artifactId>jef</artifactId>
-    <version>1.0</version>
+    <version>0.1</version>
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
@@ -133,5 +133,10 @@
             <version>${lombok.version}</version>
             <scope>compile</scope>
         </dependency>
+        <dependency>
+            <groupId>javax.persistence</groupId>
+            <artifactId>javax.persistence-api</artifactId>
+            <version>2.2</version>
+        </dependency>
     </dependencies>
 </project>
\ No newline at end of file
diff --git a/src/main/java/jef/model/DbContext.java b/src/main/java/jef/model/DbContext.java
new file mode 100644
index 0000000..530f6b9
--- /dev/null
+++ b/src/main/java/jef/model/DbContext.java
@@ -0,0 +1,4 @@
+package jef.model;
+
+public abstract class DbContext {
+}
diff --git a/src/main/java/jef/model/DbEntity.java b/src/main/java/jef/model/DbEntity.java
new file mode 100644
index 0000000..56000ec
--- /dev/null
+++ b/src/main/java/jef/model/DbEntity.java
@@ -0,0 +1,94 @@
+package jef.model;
+
+import jef.asm.AsmParseException;
+import jef.asm.AsmParser;
+import jef.expressions.Expression;
+import jef.expressions.IntermediateFieldExpression;
+import jef.serializable.SerializableFunction;
+import jef.serializable.SerializableObject;
+import lombok.Getter;
+import lombok.Setter;
+
+import java.lang.reflect.Field;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+@Getter
+@Setter
+public class DbEntity<T extends SerializableObject> {
+    private final Class<T> entityClazz;
+    private final List<DbField<?>> fields;
+    private String name;
+
+    public DbEntity(Class<T> entityClazz) {
+        this(entityClazz, new ArrayList<>());
+    }
+
+    public DbEntity(Class<T> entityClazz, List<DbField<?>> fields) {
+        this.entityClazz = entityClazz;
+        this.fields = fields;
+        this.name = entityClazz.getSimpleName();
+    }
+
+    public List<DbField<?>> getFields() {
+        return Collections.unmodifiableList(fields);
+    }
+
+    /**
+     * Returns the database model for the requested property or null if not present.
+     *
+     * @param getter the expression selecting the property
+     * @param <R>    the type of property class
+     * @return the database model for the requested property or null if not present.
+     */
+    public <R> DbField<R> getField(SerializableFunction<T, R> getter) {
+        var name = extractFieldName(getter);
+        var prop = (DbField<R>) this.fields.stream().filter(p -> p.getField().getName().equals(name)).findFirst().orElse(null);
+        return prop;
+    }
+
+    public <R> DbField<R> getOrCreateField(SerializableFunction<T, R> getter) {
+        try {
+            var prop = getField(getter);
+            if (prop == null) {
+                var name = extractFieldName(getter);
+                var field = ReflectionUtil.getFieldsRecursive(entityClazz).stream().filter(f -> f.getName().equals(name)).findFirst().orElse(null);
+                if (field == null) {
+                    throw new RuntimeException("Field not found: " + name);
+                }
+                prop = new DbField<>((Class<R>) field.getType(), field);
+                fields.add(prop);
+            }
+            return prop;
+        } catch (Exception e) {
+            throw new RuntimeException("Invalid expression", e);
+        }
+    }
+
+    public <R> DbField<R> getOrCreateField(Field f) {
+        try {
+            var prop = (DbField<R>) fields.stream().filter(e -> e.getField() == f).findFirst().orElse(null);
+            if (prop == null) {
+                prop = new DbField<>((Class<R>) f.getType(), f);
+                fields.add(prop);
+            }
+            return prop;
+        } catch (Exception e) {
+            throw new RuntimeException("Invalid expression", e);
+        }
+    }
+
+    private <R> String extractFieldName(SerializableFunction<T, R> getter) {
+        try {
+            var expr = new AsmParser(getter).parse();
+            if (expr.getType() != Expression.Type.INTERMEDIATE_FIELD) {
+                throw new RuntimeException(expr.getClass().getSimpleName() + " is not a field expression");
+            }
+            var name = ((IntermediateFieldExpression) expr).getName();
+            return name;
+        } catch (AsmParseException e) {
+            throw new RuntimeException("Invalid expression", e);
+        }
+    }
+}
diff --git a/src/main/java/jef/model/DbField.java b/src/main/java/jef/model/DbField.java
new file mode 100644
index 0000000..45802e4
--- /dev/null
+++ b/src/main/java/jef/model/DbField.java
@@ -0,0 +1,21 @@
+package jef.model;
+
+import lombok.Getter;
+import lombok.Setter;
+
+import java.lang.reflect.Field;
+
+@Getter
+@Setter
+public class DbField<T> {
+    private final Class<T> propertyClazz;
+    private final Field field;
+    private String name;
+    private boolean notNull = false;
+
+    public DbField(Class<T> propertyClazz, Field field) {
+        this.propertyClazz = propertyClazz;
+        this.field = field;
+        this.name = field.getName();
+    }
+}
diff --git a/src/main/java/jef/model/ModelBuilder.java b/src/main/java/jef/model/ModelBuilder.java
new file mode 100644
index 0000000..4ead7c8
--- /dev/null
+++ b/src/main/java/jef/model/ModelBuilder.java
@@ -0,0 +1,116 @@
+package jef.model;
+
+import jef.DbSet;
+import jef.model.annotations.Clazz;
+import jef.model.annotations.processors.AnnotationProcessor;
+import jef.model.annotations.processors.NotNullProcessor;
+import jef.serializable.SerializableObject;
+
+import javax.persistence.Transient;
+import java.lang.reflect.Field;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+public class ModelBuilder {
+    private static final List<AnnotationProcessor> annotationProcessors = new ArrayList<>();
+
+    static {
+        annotationProcessors.add(NotNullProcessor.INSTANCE);
+    }
+
+
+    public static ModelBuilder from(DbContext context) {
+        try {
+            return from0(context);
+        } catch (Exception e) {
+            throw e instanceof RuntimeException ? (RuntimeException) e : new RuntimeException(e);
+        }
+    }
+
+    private static ModelBuilder from0(DbContext context) throws Exception {
+        var mb = new ModelBuilder(new ArrayList<>());
+        for (Field ctxfield : context.getClass().getDeclaredFields()) {
+            System.out.println(ctxfield);
+            if (!DbSet.class.isAssignableFrom(ctxfield.getType())) {
+                continue;
+            }
+            Clazz clazzAnnontation = ctxfield.getAnnotation(Clazz.class);
+            if (clazzAnnontation == null) {
+                throw new ModelException("DbSet " + ctxfield.getName() + " is missing the Clazz annotation");
+            }
+            var dbsetClazz = (Class<? extends SerializableObject>)clazzAnnontation.clazz();
+            var entity = mb.getOrCreateEntity(dbsetClazz);
+
+            var fields = ReflectionUtil.getFieldsRecursive(dbsetClazz);
+            for (var f : fields) {
+                if (f.getAnnotationsByType(Transient.class).length > 0) {
+                    continue;
+                }
+                if (Collection.class.isAssignableFrom(f.getType())) {
+                    throw new UnsupportedOperationException();
+                } else {
+                    var dbField = entity.getOrCreateField(f);
+                    if (f.getType().isPrimitive()) {
+                        dbField.setNotNull(true);
+                    }
+                }
+            }
+        }
+        for (AnnotationProcessor processor : annotationProcessors) {
+            processor.apply(mb);
+        }
+        return mb;
+//        var entities = new HashMap<Class<? extends SerializableObject>, DbEntity<? extends SerializableObject>>();
+//        for (Field ctxfield : context.getClass().getDeclaredFields()) {
+//            if (!DbSet.class.isAssignableFrom(ctxfield.getClass())) {
+//                continue;
+//            }
+//            ctxfield.setAccessible(true);
+//            var dbset = (DbSet<? extends SerializableObject>) ctxfield.get(context);
+//            var dbsetClazz = dbset.getClazz();
+//            var fields = getFieldsRecursive(dbsetClazz);
+//            entities.put(dbsetClazz, createEntity(dbsetClazz, fields));
+//        }
+//
+//        return new ModelBuilder(new ArrayList<>(entities.values()));
+    }
+
+    private final List<DbEntity<? extends SerializableObject>> entities;
+
+    public ModelBuilder(List<DbEntity<? extends SerializableObject>> entities) {
+        this.entities = entities;
+    }
+
+    public List<DbEntity<? extends SerializableObject>> getEntities() {
+        return Collections.unmodifiableList(entities);
+    }
+
+    /**
+     * Returns the database model for the requested class or null if not present.
+     *
+     * @param clazz the class of the model class
+     * @param <T>   the type of model class
+     * @return the database model for the requested class or null if not present.
+     */
+    public <T extends SerializableObject> DbEntity<T> getEntity(Class<T> clazz) {
+        return (DbEntity<T>) entities.stream().filter(e -> e.getEntityClazz() == clazz).findFirst().orElse(null);
+    }
+
+    /**
+     * Returns the database model for the requested class or creates a new one if none exists.
+     *
+     * @param clazz the class of the model class
+     * @param <T>   the type of model class
+     * @return the database model for the requested class or the newly created one if none existed.
+     */
+    public <T extends SerializableObject> DbEntity<T> getOrCreateEntity(Class<T> clazz) {
+        var entity = getEntity(clazz);
+        if (entity == null) {
+            entity = new DbEntity<>(clazz);
+            entities.add(entity);
+        }
+        return entity;
+    }
+}
diff --git a/src/main/java/jef/model/ModelException.java b/src/main/java/jef/model/ModelException.java
new file mode 100644
index 0000000..9e01c8c
--- /dev/null
+++ b/src/main/java/jef/model/ModelException.java
@@ -0,0 +1,15 @@
+package jef.model;
+
+public class ModelException extends RuntimeException {
+    public ModelException(String message) {
+        super(message);
+    }
+
+    public ModelException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public ModelException(Throwable cause) {
+        super(cause);
+    }
+}
diff --git a/src/main/java/jef/model/ReflectionUtil.java b/src/main/java/jef/model/ReflectionUtil.java
new file mode 100644
index 0000000..d27bc1f
--- /dev/null
+++ b/src/main/java/jef/model/ReflectionUtil.java
@@ -0,0 +1,22 @@
+package jef.model;
+
+import jef.serializable.SerializableObject;
+
+import java.lang.reflect.Field;
+import java.util.Collection;
+import java.util.HashMap;
+
+class ReflectionUtil {
+    static Collection<Field> getFieldsRecursive(Class<? extends SerializableObject> clazz) {
+        var fields = new HashMap<String, Field>();
+        do {
+            for (Field f : clazz.getDeclaredFields()) {
+                if (!fields.containsKey(f.getName())) {
+                    fields.put(f.getName(), f);
+                }
+            }
+            clazz = (Class<? extends SerializableObject>) clazz.getSuperclass();
+        } while (clazz != SerializableObject.class);
+        return fields.values();
+    }
+}
diff --git a/src/main/java/jef/model/annotations/Clazz.java b/src/main/java/jef/model/annotations/Clazz.java
new file mode 100644
index 0000000..1590ec7
--- /dev/null
+++ b/src/main/java/jef/model/annotations/Clazz.java
@@ -0,0 +1,12 @@
+package jef.model.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.FIELD)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Clazz {
+    Class<?> clazz();
+}
diff --git a/src/main/java/jef/model/annotations/NotNull.java b/src/main/java/jef/model/annotations/NotNull.java
new file mode 100644
index 0000000..0d444f6
--- /dev/null
+++ b/src/main/java/jef/model/annotations/NotNull.java
@@ -0,0 +1,11 @@
+package jef.model.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.FIELD)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface NotNull {
+}
diff --git a/src/main/java/jef/model/annotations/processors/AnnotationProcessor.java b/src/main/java/jef/model/annotations/processors/AnnotationProcessor.java
new file mode 100644
index 0000000..b2f1c41
--- /dev/null
+++ b/src/main/java/jef/model/annotations/processors/AnnotationProcessor.java
@@ -0,0 +1,8 @@
+package jef.model.annotations.processors;
+
+import jef.model.ModelBuilder;
+
+public interface AnnotationProcessor {
+
+    void apply(ModelBuilder mb);
+}
diff --git a/src/main/java/jef/model/annotations/processors/NotNullProcessor.java b/src/main/java/jef/model/annotations/processors/NotNullProcessor.java
new file mode 100644
index 0000000..3cc9994
--- /dev/null
+++ b/src/main/java/jef/model/annotations/processors/NotNullProcessor.java
@@ -0,0 +1,25 @@
+package jef.model.annotations.processors;
+
+import jef.model.DbEntity;
+import jef.model.DbField;
+import jef.model.ModelBuilder;
+import jef.model.annotations.NotNull;
+import jef.serializable.SerializableObject;
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public class NotNullProcessor implements AnnotationProcessor {
+    public static final NotNullProcessor INSTANCE = new NotNullProcessor();
+
+    @Override
+    public void apply(ModelBuilder mb) {
+        for (DbEntity<? extends SerializableObject> entity : mb.getEntities()) {
+            for (DbField<?> field : entity.getFields()) {
+                if (field.getField().getAnnotationsByType(NotNull.class).length > 0) {
+                    field.setNotNull(true);
+                }
+            }
+        }
+    }
+}
diff --git a/src/test/java/jef/model/DbContextTest.java b/src/test/java/jef/model/DbContextTest.java
new file mode 100644
index 0000000..98a519f
--- /dev/null
+++ b/src/test/java/jef/model/DbContextTest.java
@@ -0,0 +1,62 @@
+package jef.model;
+
+import jef.DbSet;
+import jef.model.annotations.Clazz;
+import jef.serializable.SerializableObject;
+import lombok.Getter;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class DbContextTest {
+
+    @Test
+    public void test() {
+        var mb = ModelBuilder.from(new Ctx());
+        for (DbEntity<? extends SerializableObject> entity : mb.getEntities()) {
+            assertEquals("TestClass", entity.getName());
+            assertEquals(5, entity.getFields().size());
+            assertEquals(1, entity.getFields().stream().filter(e -> e.getName().equals("i")).count());
+            assertEquals(1, entity.getFields().stream().filter(e -> e.getName().equals("d")).count());
+            assertEquals(1, entity.getFields().stream().filter(e -> e.getName().equals("f")).count());
+            assertEquals(1, entity.getFields().stream().filter(e -> e.getName().equals("l")).count());
+            assertEquals(1, entity.getFields().stream().filter(e -> e.getName().equals("o")).count());
+
+            //intrinsic non null
+            assertEquals(5, entity.getFields().size());
+            assertTrue(entity.getFields().stream().filter(e -> e.getName().equals("i")).findFirst().get().isNotNull());
+            assertTrue(entity.getFields().stream().filter(e -> e.getName().equals("d")).findFirst().get().isNotNull());
+            assertTrue(entity.getFields().stream().filter(e -> e.getName().equals("f")).findFirst().get().isNotNull());
+            assertTrue(entity.getFields().stream().filter(e -> e.getName().equals("l")).findFirst().get().isNotNull());
+            assertFalse(entity.getFields().stream().filter(e -> e.getName().equals("o")).findFirst().get().isNotNull());
+        }
+    }
+
+    @Test
+    public void testMissingAnnotation() {
+        assertThrows(ModelException.class, () -> ModelBuilder.from(new CtxMissingAnnotation()));
+    }
+
+    public static class Ctx extends DbContext {
+
+        @Clazz(clazz = TestClass.class)
+        private DbSet<TestClass> objects1;
+    }
+
+    public static class CtxMissingAnnotation extends DbContext {
+
+        private DbSet<TestClass> objects1;
+    }
+
+    @Getter
+    public static class TestClass extends SerializableObject {
+        public int i = 1;
+        public Object o = new Object();
+        public double d;
+        public float f;
+        public long l;
+    }
+}
\ No newline at end of file