How to realize fuzzy query by using SQL statement
In this issue, the editor will bring you about how to use SQL sentences to achieve fuzzy query. The article is rich in content and analyzes and describes it from a professional point of view. I hope you can get something after reading this article.
In main.xml:
In the MyDatabaseHelper.java class:
Package com.li.sqlite
/ / Auxiliary operation class of database
Import android.content.Context
Import android.database.sqlite.SQLiteDatabase
Import android.database.sqlite.SQLiteOpenHelper
Public class MyDatabaseHelper extends SQLiteOpenHelper {
Private static final String DATABASENAME = "liyewen.db"
Private static final int DATABASERVERSION = 1; / / set the version of the database
Private static final String TABLENAME = "mytab"
Public MyDatabaseHelper (Context context) {/ / users are definitely only concerned about Context
Super (context, DATABASENAME, null, DATABASERVERSION)
}
@ Override
Public void onCreate (SQLiteDatabase db) {/ / create datasheet
String sql = "CREATE TABLE" + TABLENAME + "("
+ "id INTEGER PRIMARY KEY," / / set to Integer in SQLite, PRIMARY KEY will automatically increase ID
+ "name VARCHAR (50) NOT NULL,"
+ "birthday DATE NOT NULL" + ")"
Db.execSQL (sql); / / execute SQL
System.out.println ("* create: onCreate ().")
}
@ Override
Public void onUpgrade (SQLiteDatabase db, int oldVersion, int newVersion) {
String sql = "DROP TABLE IF EXISTS" + TABLENAME
Db.execSQL (sql)
System.out.println ("* Update: onUpgrade ().")
This.onCreate (db)
}
}
In the MytabCursor.java class:
Package com.li.sqlite
Import java.util.ArrayList
Import java.util.List
Import android.database.Cursor
Import android.database.sqlite.SQLiteDatabase
Public class MytabCursor {
Private static final String TABLENAME = "mytab"
Private SQLiteDatabase db = null
Public MytabCursor (SQLiteDatabase db) {
This.db = db
}
Public List find () {
List all = new ArrayList (); / / it's just String at this time
String sql = "SELECT id,name,birthday FROM" + TABLENAME + "WHERE name LIKE? OR birthday LIKE?"
String keyWord = "2"; / / query keyword, which should be defined by the method
String args [] = new String [] {"%" + keyWord + "%", "%" + keyWord + "%"}
Cursor result = this.db.rawQuery (sql, args); / / execute query statement
For (result.moveToFirst ();! result.isAfterLast (); result.moveToNext ()) {/ / retrieve data in a circular manner
All.add ("[" + result.getInt (0) + "]" + "" + result.getString (1)
+ "," + result.getString (2)
}
This.db.close ()
Return all
}
}
In MySQLiteDemo.java:
Package com.li.sqlite
Import android.app.Activity
Import android.database.sqlite.SQLiteOpenHelper
Import android.os.Bundle
Import android.view.View
Import android.view.View.OnClickListener
Import android.widget.ArrayAdapter
Import android.widget.Button
Import android.widget.LinearLayout
Import android.widget.ListView
Public class MySQLiteDemo extends Activity {
Private Button findBut = null
Private SQLiteOpenHelper helper = null
Private LinearLayout mylayout = null
@ Override
Public void onCreate (Bundle savedInstanceState) {
Super.onCreate (savedInstanceState)
Super.setContentView (R.layout.main)
This.findBut = (Button) super.findViewById (R.id.findBut)
This.mylayout = (LinearLayout) super.findViewById (R.id.mylayout)
This.findBut.setOnClickListener (new OnClickListenerImpl ())
}
Private class OnClickListenerImpl implements OnClickListener {
Public void onClick (View v) {
MySQLiteDemo.this.helper = new MyDatabaseHelper (MySQLiteDemo.this)
ListView listView = new ListView (MySQLiteDemo.this)
ListView.setAdapter (/ / set data
New ArrayAdapter / / all data is a string
(MySQLiteDemo.this, / / context
Android.R.layout.simple_list_item_1, / / layout displayed in the list
New MytabCursor (/ / instantiate query
MySQLiteDemo.this.helper.getReadableDatabase () / / get the SQLiteDatabase object
.find ()); / / call the find () method and return List
MySQLiteDemo.this.mylayout.addView (listView)
}
}
}
The above is the editor for you to share how to use SQL statements to achieve fuzzy query, if you happen to have similar doubts, you might as well refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.
