Android Room - 2 (SQLite Simple Ex)

 Room이 좋다는 것을 알기 전에, SQlite가 어떤 식으로 동작하는지는 알아야, Room과 비교할 수 있겟죠?

 

 간단하게 SQLite을 어떻게 쓰는지 코드로 알아보겠습니다.

 

 전체적인 느낌은 DB에 SQL문을 날릴 때의 느낌과 유사합니다. 간단하게 INSERT/GETALL/DELETE 정도만 구현해봤습니다.

 

  

 

	class MainActivity : AppCompatActivity() {
	lateinit var db : SQLiteHelperSample
	override fun onCreate(savedInstanceState: Bundle?) {
	super.onCreate(savedInstanceState)
	setContentView(R.layout.activity_main)
	db = SQLiteHelperSample(this)
	val insertBtn = findViewById<Button>(R.id.insert)
	insertBtn.setOnClickListener {
	db.insert()
	}
	val getBtn = findViewById<Button>(R.id.getAll)
	getBtn.setOnClickListener {
	db.getAllData()
	}
	val deleteBtn = findViewById<Button>(R.id.deleteAll)
	deleteBtn.setOnClickListener {
	db.deleteAll()
	}
	}
	override fun onDestroy() {
	super.onDestroy()
	db.close()
	}
	}

view raw MainActivity.kt hosted with ❤ by GitHub

	class SQLiteHelperSample(context : Context) : SQLiteOpenHelper(context, DATABASE_NAME, null, DATABASE_VERSION){
	companion object {
	private const val DATABASE_VERSION = 1
	private const val DATABASE_NAME = "my.db"
	private const val TBL_NAME = "my_table"
	private const val ID = "id"
	private const val TITLE = "title"
	private const val CONTENT = "content"
	}
	override fun onCreate(db: SQLiteDatabase?) {
	val SQL_CREATE_ENTRIES =
	"CREATE TABLE $TBL_NAME (" +
	"$ID INTEGER PRIMARY KEY," +
	"$TITLE TEXT," +
	"$CONTENT TEXT)"
	db?.execSQL(SQL_CREATE_ENTRIES)
	}
	fun insert(){
	Log.e("insert", "insert")
	val db = this.writableDatabase
	val values = ContentValues().apply {
	put(TITLE, "TITLE")
	put(CONTENT, "CONTENT")
	}
	db.insert(TBL_NAME, null, values)
	}
	fun getAllData(){
	Log.e("getAllData", "getAllData")
	val db = this.readableDatabase
	val query = "SELECT * FROM $TBL_NAME"
	val cursor = db.rawQuery(query, null)
	with(cursor) {
	while (moveToNext()) {
	Log.e("this", getInt(0).toString())
	Log.e("this", getString(1))
	Log.e("this", getString(2))
	}
	}
	}
	fun deleteAll(){
	Log.e("deleteAll", "deleteAll")
	val db = this.writableDatabase
	db.execSQL("DELETE FROM $TBL_NAME")
	}
	// Version Upgrade
	override fun onUpgrade(db: SQLiteDatabase?, oldVersion: Int, newVersion: Int) {
	db?.execSQL("DROP TABLE IF EXISTS $TBL_NAME")
	onCreate(db)
	}
	}

view raw SQLiteHelperSample.kt hosted with ❤ by GitHub

	<?xml version="1.0" encoding="utf-8"?>
	<LinearLayout
	xmlns:android="http://schemas.android.com/apk/res/android"
	xmlns:app="http://schemas.android.com/apk/res-auto"
	xmlns:tools="http://schemas.android.com/tools"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	tools:context=".MainActivity">
	<Button
	android:id="@+id/insert"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:text="insert"
	/>
	<Button
	android:id="@+id/getAll"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:text="getAll"
	/>
	<Button
	android:id="@+id/deleteAll"
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:text="delete"/>
	</LinearLayout>

view raw activity_main.xml hosted with ❤ by GitHub

 

 

 

 - 참조

 

https://developer.android.com/training/data-storage/sqlite?hl=ko 

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