P2

relational

nosql

SQL: structured query language

P3: download on MAC： Just follow the instructions

after downloading the sql server, a graphic tool is needed to connect to the server and manage the database

一頭霧水但是跟著做完了，下好了希望學的時候能有點頭緒。

step1:first 4 sessions:

retrieve, insert, update and delete data

step 2:

summarizing data

writing complex queries

built-in functions

views

stored procedures

step 3:

triggers

events

transactions

concurrency

step 4:

designing databases

indexing for high performance

securing database: create user account/ limit the access

use sql_store

所有這些字句都可以選，但是不能改變順序

from-》where-〉order by

給行賦名：

AS

how to create column name with space:

唯一值返回？

>

>=

<

<=

=

!= 不等號

<> 不等號

優(yōu)先級 AND > OR

用括號來改變優(yōu)先級

NOT

每日打卡+現(xiàn)實打工輔助實踐，看看多久能學完：

2023/02/22: 第一章P1-P6 第二章P7-P9

2023/02/23: