Database systems have been the critical part of every data-intensive application in the past decades. Nowadays machine learning techniques open up the opportunities to improve the performance as well as usability of database systems by replacing some human labored tasks or heuristic approached with learned models. In this seminar, I will introduce two pieces of up-to-date research work in the database community. The first one is learned index structure. The basic idea is of the first paper is to regard index structures in the database as mapping a key to the position of a record within an array. Then the functionality of indexes can be realized by several trained models. The second one is query-based workload forecasting for a database system. To make the database system “self-driving”, it requires the database system to automatically choose its optimizations without human intervention. To reach this goal, the second paper constructs a toolkit QB5000, which can predict the incoming workload of DBMS by first clustering query workloads into templates and then use a variety of machine learning models, such as LR, KR, and RNN for forecasting. References: [1] Tim Kraska, Alex Beutel, Ed H. Chi, Jeffrey Dean, Neoklis Polyzotis. The Case for Learned Index Structures. SIGMOD Conference 2018: 489-504. [2] Lin Ma, Dana Van Aken, Ahmed Hefny, Gustavo Mezerhane, Andrew Pavlo, Geoffrey J. Gordon.Query-based Workload Forecasting for Self-Driving Database Management Systems. SIGMOD Conference 2018: 631-645.