code: from time import time_ns
  import lancedb
  
  uri = "./.lancedb"
  db = lancedb.connect(uri)
  tns = db.table_names()
  print(tns)
  tn = 'my_table'
  
  now = time_ns()
  if (tn not in tns):
      # 创建表的时候就确定了字段结构了。
      # 之后通过 add 添加字段无效。
      table = db.create_table(
          tn,
          data=[
              {"vector": [3.1, 4.1], "item": "foo", "price": 10.0, "createAt": now},
              {"vector": [5.9, 26.5], "item": "bar", "price": 20.0, "createAt": now},
          ],
      )
  else:
      table = db.open_table(tn)
      table.add(
          data=[
              {"vector": [3.1, 4.1], "item": "foo", "price": 10.0, "createAt": now},
              {"vector": [5.9, 26.5], "item": "bar", "price": 20.0, "createAt": now},
          ],
      )
      df = table.to_pandas()
      print(df)
apis: lancedb.connect
extract_api: [((65, 85), 'lancedb.connect', 'lancedb.connect', (['uri'], {}), '(uri)\n', (80, 85), False, 'import lancedb\n'), ((143, 152), 'time.time_ns', 'time_ns', ([], {}), '()\n', (150, 152), False, 'from time import time_ns\n')]