From 72c4f972a0daaca7081abc7ccfa90bc07ec5db7e Mon Sep 17 00:00:00 2001
From: Alice Gaudon <alice@gaudon.pro>
Date: Wed, 26 Aug 2020 14:18:02 +0200
Subject: [PATCH] Cache model existence to support insert + update in the same
 transaction

---
 src/db/Model.ts | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/db/Model.ts b/src/db/Model.ts
index b1a291a..e1dcf29 100644
--- a/src/db/Model.ts
+++ b/src/db/Model.ts
@@ -43,6 +43,7 @@ export default abstract class Model {
     protected readonly _factory: ModelFactory<any>;
     private readonly _components: ModelComponent<any>[] = [];
     private readonly _validators: { [key: string]: Validator<any> } = {};
+    private _cached_exists?: boolean = undefined;
 
     [key: string]: any;
 
@@ -155,6 +156,7 @@ export default abstract class Model {
             const result = await query(`INSERT INTO ${this.table} (${properties.join(', ')}) VALUES(${props_holders.join(', ')})`, values, connection);
 
             if (this.hasOwnProperty('id')) this.id = result.other.insertId;
+            this._cached_exists = true;
         }
 
         return needs_full_update;
@@ -168,14 +170,19 @@ export default abstract class Model {
             query = query.where(indexField, this[indexField]);
         }
         await query.execute();
+        this._cached_exists = false;
     }
 
     public async exists(): Promise<boolean> {
-        let query = this._factory.select('1');
-        for (const indexField of this._factory.getPrimaryKeyFields()) {
-            query = query.where(indexField, this[indexField]);
+        if (this._cached_exists === undefined) {
+            const query = this._factory.select('1');
+            for (const indexField of this._factory.getPrimaryKeyFields()) {
+                query.where(indexField, this[indexField]);
+            }
+            this._cached_exists = (await query.limit(1).execute()).results.length > 0;
         }
-        return (await query.limit(1).execute()).results.length > 0;
+
+        return this._cached_exists;
     }
 
     public async validate(onlyFormat: boolean = false, connection?: Connection): Promise<void[]> {