Android SQLite数据库
前言
以前写PHP的时候，内置了print_r()和var_dump()两个函数用于打印输出任意类型的数据内部结构，现在做Android的开发，发现并没有这种类似的函数，对于数据库的查看很不方便，于是就写了一下查看数据库表的方法代码。
代码实现
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 | 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(); //核心区 //读取系统表 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())); //打印当前数据库中的所有表 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()); } } }); }} |
功能扩展
查看表是否存在
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | 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;} |
查看数据库中有哪些表
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | 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;}</string></string></string> |
感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！
