implementing patches

lib/snippets/database/classes/Database.ts

@@ -2,4 +2,13 @@ import { Table } from './Table';
 
 export class Database {
   public tables: Array<Table> = [];
+
+  public get_table (name: string): Table|null {
+    for (const table of this.tables) {
+      if (table.name === name)
+        return table;
+    }
+
+    return null;
+  }
 }

lib/snippets/database/classes/PatchAction.ts

@@ -0,0 +1,5 @@
+import { Database } from './Database';
+
+export interface PatchAction {
+  apply(db: Database): void;
+}

lib/snippets/database/classes/Table.ts

@@ -7,4 +7,13 @@ export class Table {
   public constructor (name: string) {
     this.name = name;
   }
+
+  public get_column (name: string): Column|null {
+    for (const col of this.columns) {
+      if (col.name === name)
+        return col;
+    }
+
+    return null;
+  }
 }