fix: add try-catch to get error message

content/spin/v3/rdbms-storage.md

@@ -89,13 +89,18 @@ const DB_URL = "mysql://root:@127.0.0.1/spin_dev"
 */
 
 export async function handler(_req: Request, res: ResponseBuilder) {
-  let conn = Mysql.open(DB_URL);
-  conn.execute('delete from test where id=$1', [4]);
-  conn.execute('insert into test values (4,5)', []);
-  let ret = conn.query('select * from test', []);
-  // return a object that looks like 
-  // { "columns": [{name: "id", dataType: "int32"}], "rows": [{ "id": 4, "val": 5 }] }
-  res.send(JSON.stringify(ret, null, 2));
+  try {
+    let conn = Mysql.open(DB_URL);
+    conn.execute('delete from test where id=$1', [4]);
+    conn.execute('insert into test values (4,5)', []);
+    let ret = conn.query('select * from test', []);
+    // return a object that looks like 
+    // { "columns": [{name: "id", dataType: "int32"}], "rows": [{ "id": 4, "val": 5 }] }
+    res.send(JSON.stringify(ret, null, 2));
+  } catch (error) {
+    console.log(error.payload);
+	res.send({});
+  }
 }
 ```