MM_30476 : ADDED Schema Managers

* The migration array will hold all the migration steps.

*  The initial app release (e.g. v2 )will have an empty array and subsequent releases  (e.g.  v2.1 ) will have the steps listed in that array.

* On initialization, the database will perform the migration to accomodate for new columns/tables creation and while it will conserve the mobile phone's data, it will also make it conform to this new schema.

* If a migration fails, the migration process will rollback any changes.  This migration will be thoroughly tested in development before pushing it live.

app/constants/database.ts

@@ -1,6 +1,8 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
 
+import keyMirror from '@utils/key_mirror';
+
 export const MM_TABLES = {
     DEFAULT: {
         APP: 'app',
@@ -39,6 +41,12 @@ export const MM_TABLES = {
     },
 };
 
+export const DB_NAME = keyMirror({
+    DEFAULT_DATABASE: null,
+    SERVER_DATABASE: null,
+});
+
 export default {
+    DB_NAME,
     MM_TABLES,
 };

app/database/default/migration/index.ts

@@ -1,8 +1,9 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
-import {schemaMigrations} from '@nozbe/watermelondb/Schema/migrations';
+import {Migration} from '@nozbe/watermelondb/Schema/migrations';
 
 // NOTE : To implement migration, please follow this document
 // https://nozbe.github.io/WatermelonDB/Advanced/Migrations.html
 
-export default schemaMigrations({migrations: []});
+export const migrations: Migration [] = [];
+

app/database/managers/schema_manager.ts

@@ -0,0 +1,22 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import {SQLiteAdapterOptions} from '@nozbe/watermelondb/adapters/sqlite';
+import {defaultSchema} from '../default/schema';
+import {DB_NAME} from '@constants/database';
+import {migrations as defaultMigration} from '../default/migration';
+import {migrations as serverMigration} from '../server/migration';
+import {schemaMigrations} from '@nozbe/watermelondb/Schema/migrations';
+import {serverSchema} from '../server/schema';
+
+export const default_schema_manager:SQLiteAdapterOptions = {
+    dbName: DB_NAME.DEFAULT_DATABASE,
+    schema: defaultSchema,
+    ...(defaultMigration.length > 0 && {migrations: schemaMigrations({migrations: defaultMigration})}),
+};
+
+export const server_schema_manager:SQLiteAdapterOptions = {
+    dbName: DB_NAME.SERVER_DATABASE,
+    schema: serverSchema,
+    ...(serverMigration.length > 0 && {migrations: schemaMigrations({migrations: serverMigration})}),
+};

app/database/server/migration/index.ts

@@ -1,8 +1,8 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
-import {schemaMigrations} from '@nozbe/watermelondb/Schema/migrations';
+import {Migration} from '@nozbe/watermelondb/Schema/migrations';
 
 // NOTE : To implement migration, please follow this document
 // https://nozbe.github.io/WatermelonDB/Advanced/Migrations.html
 
-export default schemaMigrations({migrations: []});
+export const migrations: Migration [] = [];

app/database/server/schema/index.ts

@@ -3,7 +3,7 @@
 import {AppSchema, appSchema, tableSchema} from '@nozbe/watermelondb';
 import {MM_TABLES} from '@constants/database';
 
-export const defaultSchema: AppSchema = appSchema({
+export const serverSchema: AppSchema = appSchema({
     version: 1,
     tables: [
         tableSchema({