diff --git a/code/common/db/readme.md b/code/common/db/readme.md
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+++ b/code/common/db/readme.md
@@ -0,0 +1,18 @@
+# DB
+
+This module primarily contains SQL files for the URLs database. The most central tables are `EC_DOMAIN`, `EC_URL` and `EC_PAGE_DATA`.
+
+## Central Paths
+
+* [current](src/main/resources/sql/current) - The current database model
+* [migrations](src/main/resources/sql/migrations)
+
+## See Also 
+
+* [common/service](../service) implements DatabaseModule, which is from where the services get database connections.
+
+## Relation diagrams for EC_DOMAIN and EC_URL
+
+![image](../../../doc/sql/er-diagram-domain.png)
+
+![image](../../../doc/sql/er-diagram-url.png)
diff --git a/code/common/service/src/main/java/nu/marginalia/service/module/DatabaseModule.java b/code/common/service/src/main/java/nu/marginalia/service/module/DatabaseModule.java
index ce88599a..8a51d141 100644
--- a/code/common/service/src/main/java/nu/marginalia/service/module/DatabaseModule.java
+++ b/code/common/service/src/main/java/nu/marginalia/service/module/DatabaseModule.java
@@ -21,9 +21,9 @@ import java.util.Properties;
 public class DatabaseModule extends AbstractModule {
     private static final Logger logger = LoggerFactory.getLogger(DatabaseModule.class);
 
-    private static final String DB_USER_KEY="db.user";
-    private static final String DB_PASS_KEY ="db.pass";
-    private static final String DB_CONN_KEY ="db.conn";
+    private static final String DB_USER_KEY = "db.user";
+    private static final String DB_PASS_KEY = "db.pass";
+    private static final String DB_CONN_KEY = "db.conn";
 
     private final Properties dbProperties;
 
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