Udacity Android Learning Note: Lesson 4 Part A

Udacity Android Learning Note: Lesson 4 Part A

/titer1/archimedes of dry Goods shop chores
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SQL lesson

4a-15课开始，之前主要是基础 activity life cycle

SQL table looks like this.

• SELECT * from weather where data = Blalla

• SELECT * FROM Weather ORDER by Max DESC LIMIT 1//have a try

• More SQL operation

  • Delete rows
  • Update rows
  • Insert Rows
  • Add columns

• More SQL APIs in Android
  Get a simple use effect like UrlBuilder

• More about Data stroage

Overview Arch repeatedly

4a18

Intro to weather Contract

See also Solution weather table colums Solutions

INNER JOIN 2 Tables

Rest time

Don asked the new scholar to delve into the key points of foreign key and joins (in Lesson 4a-23)

Our weather contact

Practice.. Code Time Weathercontract.java

Don shows key/foreign key in detail.

Define constants in contract

Locationentry

Chapter II Sqllite Open Helper and Sunshine database repeated the next station map began to move

Weatherdbhelper Code

-Database name

-related statements for the database
-Create TABLE
-Specify foreign keys

Database testing

The result was not passed.
The approximate reason is that only weather.db has been created and no locatin.db has been created

Next to modify

Here's the next one to make up for the rest of the DB,

Create Sunshine Location DB Solution

SQLite Open Helper on Upgrade

Database upgrade.

-Must manually change the database version number?
-Database changes
-Row Changes
-Column Changes
-Overall structural changes

• When does it happen?

Chapter III ReadWrite from a database3.1 overview

3.2 Plan

3.3 Difficulty Query

3.4 Code Practice repeatedly

第三章节的代码 集中于此

The key is to execute the previous checklist and write the testlocationtable.

The same principle is used to test Weathertable.ok, let go

End

It took me 2 hours to thank Don for his company.
-Data storage Diagram overview
-Activity lifecycle, changes when rotating the screen (pause. Restart?)
-Database Test

Udacity Android Learning Note: Lesson 4 Part A