diff --git a/pos-frontend/__test__/db.test.jsx b/pos-frontend/__test__/db.test.jsx
index 7e8c994..fb6348a 100644
--- a/pos-frontend/__test__/db.test.jsx
+++ b/pos-frontend/__test__/db.test.jsx
@@ -1,9 +1,22 @@
 import '@testing-library/jest-dom'
 import pl from 'nodejs-polars'
-import { test_x } from '../app/database'
+import { test_x, create_csv_database, add_row, print_head, delete_row_by_key, save_db } from '../app/database'
 
 describe('DATABASE', () => {
   it('DATA', () => {
     test_x()
   })
+
+  it('create csv', () => {
+    let res = create_csv_database('csv_db/x.csv')
+    print_head(res)
+
+    add_row(res, { "key": ["x"], "value": ["y"] })
+    print_head(res)
+
+    save_db(res)
+
+    delete_row_by_key(res, "x")
+    print_head(res)
+  })
 })
diff --git a/pos-frontend/__test__/fire.test.jsx b/pos-frontend/__test__/fire.test.jsx
index 5605b29..d19c048 100644
--- a/pos-frontend/__test__/fire.test.jsx
+++ b/pos-frontend/__test__/fire.test.jsx
@@ -3,4 +3,12 @@ describe('Database 2', () => {
     // so do firebase
     // and can optionally have a local index if needed
   })
+
+  it('Hi', () => {
+    let x = "hi" == "hi"
+    let y = "hi2" == "hi"
+
+    console.log(x)
+    console.log(y)
+  })
 })
diff --git a/pos-frontend/app/database.ts b/pos-frontend/app/database.ts
index 014f54b..da3b5b7 100644
--- a/pos-frontend/app/database.ts
+++ b/pos-frontend/app/database.ts
@@ -1,5 +1,5 @@
 import pl, { DataFrame } from 'nodejs-polars'
-import fs from 'fs'
+import fs, { writeFile } from 'fs'
 
 export function test_x(params: any) {
   const fooSeries = pl.Series("foo", [1, 2, 3])
@@ -38,20 +38,12 @@ class CSVDatabase {
   }
 
   read(filter: Record<string, any>) {
-    if (this.df) {
-      return this.df.filter(filter)
-    }
-    return null
+    return this.df ? this.df.filter(filter) : null
   }
 
   update(filter: Record<string, any>, values: Record<string, any>) {
     if (this.df) {
-      // this.df = this.df.withColumn(
-      //   Object.keys(values)[0],
-      //   this.df
-      //     .filter(filter)
-      //     .withColumn(Object.keys(values)[0], pl.lit(values[Object.keys(values)[0]]))
-      // )
+      // update it
       this.saveCSV()
     }
   }
@@ -64,3 +56,41 @@ class CSVDatabase {
     }
   }
 }
+
+// A CSV can refer to other CSV's via pointers, a type of metadata
+
+interface CSVDatabase2 {
+  df: DataFrame
+  filepath: string
+}
+
+export function create_csv_database(filepath: string): CSVDatabase2 {
+  // let df = DataFrame([], { columns: ["key", "value"] })
+  let df = DataFrame({ "key": ['header'], "value": ['next'] })
+
+  // writeFile(filepath, 'key,value\nheader,next', () => { })
+  // let df = pl.readCSV(filepath)
+  df.writeCSV(filepath)
+
+  return { df, filepath }
+}
+
+export function save_db(db: CSVDatabase2) {
+  db.df.writeCSV(db.filepath)
+}
+
+export function add_row(db: CSVDatabase2, row: Record<string, string>) {
+  db.df = db.df.vstack(DataFrame(row))
+}
+
+export function print_head(db: CSVDatabase2) {
+  console.log(db.df.head())
+}
+
+// can filter everything that is not the row, and do to db
+
+export function delete_row_by_key({df, filepath}: CSVDatabase2, key: string) {
+  // db.df.drop(pl.col("key").eq(key))
+  // df = df.select((pl.col("key") != key).alias("nrs > 1"))
+  // db.df = db.df.filter(pl.col("key").neq(key))
+}
diff --git a/pos-frontend/csv_db/x.csv b/pos-frontend/csv_db/x.csv
new file mode 100644
index 0000000..ca11190
--- /dev/null
+++ b/pos-frontend/csv_db/x.csv
@@ -0,0 +1,3 @@
+key,value
+header,next
+x,y