diff --git a/packages/koishi-core/package.json b/packages/koishi-core/package.json
index 9819133b0b..ea8562cb35 100644
--- a/packages/koishi-core/package.json
+++ b/packages/koishi-core/package.json
@@ -34,6 +34,7 @@
   "devDependencies": {
     "@types/debug": "^4.1.5",
     "@types/ws": "^6.0.4",
+    "get-port": "^5.1.0",
     "koishi-database-level": "^1.0.3",
     "koishi-test-utils": "^1.0.3"
   },
@@ -41,7 +42,6 @@
     "axios": "^0.19.0",
     "debug": "^4.1.1",
     "escape-string-regexp": "^2.0.0",
-    "get-port": "^5.1.0",
     "koishi-utils": "^1.0.2",
     "leven": "^3.1.0",
     "ws": "^7.2.1"
diff --git a/packages/koishi-core/src/database.ts b/packages/koishi-core/src/database.ts
index c42ae7fb3f..9b17ba8e4c 100644
--- a/packages/koishi-core/src/database.ts
+++ b/packages/koishi-core/src/database.ts
@@ -153,13 +153,15 @@ export interface AbstractDatabase {
   stop? (): void | Promise<void>
 }
 
+const unknownMethods: { [K in SubdatabaseType]?: DatabaseInjections<K> } = {}
+const unknownOptions: { [K in SubdatabaseType]?: TableConfig<K> } = {}
 const subdatabases: { [K in SubdatabaseType]?: Subdatabase<K> } = {}
 const existingDatabases: { [K in SubdatabaseType]?: DatabaseMap } = {}
 
 export function registerDatabase <K extends SubdatabaseType> (name: K, subdatabase: Subdatabase<K, {}>) {
   subdatabases[name] = subdatabase as any
-  subdatabase._methods = {}
-  subdatabase._options = {}
+  subdatabase._methods = unknownMethods[name] ?? {}
+  subdatabase._options = unknownOptions[name] ?? {}
 }
 
 export type DatabaseInjections <K extends SubdatabaseType, T extends TableType = TableType> = {
@@ -175,24 +177,26 @@ export function injectMethods <K extends SubdatabaseType, T extends TableType> (
   options?: TableConfig<K>,
 ) {
   const Subdatabase = subdatabases[name] as Subdatabase<K>
-  if (!Subdatabase) return
-  if (Subdatabase._manager) {
-    const config = Subdatabase._manager.config[name]
-    if (!config) return
-    if (!Subdatabase._manager.database[name]) {
-      Subdatabase._manager.createSubdatabase(name, config)
-    }
-    Subdatabase._manager.injectMethods(name, table, methods)
+  let methodMap: Partial<Record<TableType, DatabaseInjections<K, T>>>
+  let optionMap: Partial<Record<TableType, TableConfig<K>>>
+
+  // inject before subdatabase was registered
+  if (!Subdatabase) {
+    methodMap = unknownMethods[name] || (unknownMethods[name] = {} as never)
+    optionMap = unknownOptions[name] || (unknownOptions[name] = {} as never)
   } else {
-    Subdatabase._methods[table] = {
-      ...Subdatabase._methods[table] as any,
-      ...methods as any,
+    optionMap = Subdatabase._options
+    if (Subdatabase._manager) {
+      // inject after application was created
+      Subdatabase._manager.injectMethods(name, table, methods)
+      methodMap = {} as any
+    } else {
+      methodMap = Subdatabase._methods
     }
   }
-  Subdatabase._options[table] = {
-    ...Subdatabase._options[table] as any,
-    ...options as any,
-  }
+
+  methodMap[table] = { ...methodMap[table], ...methods }
+  optionMap[table] = { ...optionMap[table] as any, ...options as any }
 }
 
 class DatabaseManager {
diff --git a/packages/koishi-core/tests/database.spec.ts b/packages/koishi-core/tests/database.spec.ts
index ffdf03896d..c52d17f236 100644
--- a/packages/koishi-core/tests/database.spec.ts
+++ b/packages/koishi-core/tests/database.spec.ts
@@ -53,9 +53,6 @@ class BarDatabase {
   constructor (public options: BarOptions) {}
 }
 
-registerDatabase('foo', FooDatabase)
-registerDatabase('bar', BarDatabase)
-
 injectMethods('foo', 'user', {
   myUserFunc1 () {
     return 'my-foo-user-func'
@@ -68,6 +65,9 @@ injectMethods('foo', 'user', {
   },
 })
 
+registerDatabase('foo', FooDatabase)
+registerDatabase('bar', BarDatabase)
+
 injectMethods('bar', 'user', {
   myUserFunc1 () {
     return 'my-bar-user-func'
@@ -117,7 +117,8 @@ describe('multiple databases', () => {
     expect(() => new App({
       database: {
         foo: { value: 1 },
-        bar: {},
+        // make coverage happy
+        bar: { identifier: 'id' },
       },
     })).toThrow()
   })