Android SQLite數(shù)據(jù)庫
前言
以前寫PHP的時候,內(nèi)置了print_r()和var_dump()兩個函數(shù)用于打印輸出任意類型的數(shù)據(jù)內(nèi)部結(jié)構(gòu),現(xiàn)在做Android的開發(fā),發(fā)現(xiàn)并沒有這種類似的函數(shù),對于數(shù)據(jù)庫的查看很不方便,于是就寫了一下查看數(shù)據(jù)庫表的方法代碼。
代碼實現(xiàn)
import java.util.Arrays;import android.app.Activity;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class SecondActivity extends Activity { public static final String TAG = "Debug Info"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); ((Button)findViewById(R.id.btnQue)).setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { MyDatabaseHelper dbhelper = new MyDatabaseHelper(SecondActivity.this, "BookStore.db", null, 1); SQLiteDatabase db = dbhelper.getWritableDatabase(); //核心區(qū) //讀取系統(tǒng)表 sqlite_master String sql = "select * from sqlite_master"; Cursor cursor = db.rawQuery(sql, null); //打印表的所有列名 Log.i(TAG, Arrays.toString(cursor.getColumnNames())); //打印當前數(shù)據(jù)庫中的所有表 if (cursor.moveToFirst()) { do { String str = ""; for (String item : cursor.getColumnNames()) { str += item + ": " + cursor.getString(cursor.getColumnIndex(item)) + "/n"; } Log.i(TAG, str); } while (cursor.moveToNext()); } } }); }}功能擴展
查看表是否存在
public Boolean tableIsExist(SQLiteDatabase db, String tableName){ boolean result = false; Cursor cursor = null; if(tableName == null){ return result; } String sql = "select count(*) from sqlite_master where type ='table' and name ='"+tableName.trim()+"'"; cursor = db.rawQuery(sql, null); if(cursor.moveToNext()){ if(cursor.getInt(0) > 0){ result = true; } } return result;} 查看數(shù)據(jù)庫中有哪些表
public ArrayList<String> tablesInDB(SQLiteDatabase db){ ArrayList<String> list = new ArrayList<String>(); String sql = "select name from sqlite_master where type='table'"; Cursor cursor = db.rawQuery(sql, null); if (cursor.moveToFirst()) { do { list.add(cursor.getString(0)); } while (cursor.moveToNext()); } return list;}感謝閱讀,希望能幫助到大家,謝謝大家對本站的支持!
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