此文章作为自己的一个记录,方便自己以后复习

public class DbHelper extends SQLiteOpenHelper {
private SQLiteDatabase db = null;
private Cursor cursor = null;
private String TAG = "DBTest";
private boolean isInit;
private String createString;

public DbHelper(Context context, String dbName, SQLiteDatabase.CursorFactory factory,
int version) {
super(context, dbName, factory, version);
}

// 建表
@Override
public void onCreate(SQLiteDatabase db) {
this.db = db;
db.execSQL(createString);
}

public void inItDb(String createString) {
if (isInit)
return;
this.createString = createString;
this.isInit = true;
}

// 增
public void insert(ContentValues values, String tableName) {
SQLiteDatabase db = getWritableDatabase();
System.out.println("values" + values.get("id") + values.get("name")
+ values.get("age"));
db.insert(tableName, null, values);
Log.i(TAG, "增加一行");
db.close();
}

// 删除某一行
public void delete(String id, String tableName) {
// if (db == null) {
SQLiteDatabase db = getWritableDatabase();
// }
db.delete(tableName, "id=?", new String[]{String.valueOf(id)});
Log.i(TAG, "删除一行");
}

// 更新某一行
public void update(ContentValues values, String string, String tableName) {
SQLiteDatabase db = getWritableDatabase();
db.update(tableName, values, "id=?", new String[]{string});
db.close();
Log.i(TAG, "更新一行");
}

// 按id查询
public Cursor query(String string, String tableName) {
SQLiteDatabase db = getWritableDatabase();
System.out.println("id---->" + string);
cursor = db.query(tableName, null, "id=?", new String[]{string},
null, null, null);
Log.i(TAG, "按id查询一行");
return cursor;
}

public Cursor query(String tableName) {
SQLiteDatabase db = getWritableDatabase();
cursor = db.query(tableName, null, null, null, "id", null, "id");
Log.i(TAG, "查询所有");

return cursor;
}

public boolean deleteDatabase(Context context, String DBName) {
return context.deleteDatabase(DBName);
}

// 按sql语句操作数据库
public void handleBySql(String TabName) {
String sqsl = "update sqlite_sequence set seq=0 where name='" + TabName + "'";
SQLiteDatabase db = getWritableDatabase();
db.execSQL(sqsl);
Log.i(TAG, "执行sql语句");


}

/**
* 判断某张表是否存在
*
* @return
*/
public boolean tabbleIsExist(String tableName) {
boolean result = false;
if (tableName == null) {
return false;
}
SQLiteDatabase db = null;
Cursor cursor = null;
try {
db = this.getReadableDatabase();
String sql = "select count(*) as c from Sqlite_master where type ='table' and name ='" + tableName.trim() + "' ";
cursor = db.rawQuery(sql, null);
if (cursor.moveToNext()) {
int count = cursor.getInt(0);
if (count > 0) {
result = true;
}
}

} catch (Exception e) {
// TODO: handle exception
}
return result;
}

// 关闭数据库
public void close() {
if (db != null) {
db.close();
db = null;
}
if (cursor != null) {
cursor.close();
cursor = null;
}

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

}

//清空搜索记录
public void deleteAllRecords() {
db = this.getWritableDatabase();
db.execSQL("delete from TabOther");
db.close();
}

/**
* 创建表
*
* @return
*/
public static String getOther(String tablename) {
return "Create Table " + tablename + "( id text not null, name text )";
}
//在Activity中使用
//初始化
dbHelper = new DbHelper(this, DB, null, 1);
dbHelper.inItDb(dbHelper.getOther(TabOther));
//添加数据
ContentValues values = new ContentValues();
values.put("id", num + "");
values.put("name", name + "");
dbHelper.insert(values, TabOther);
//查询数据
/**
* 查询数据库
*
* @return
*/
public List<CoordinateAlterSample> queryAll() {
List<CoordinateAlterSample> rst = new ArrayList<CoordinateAlterSample>();
// 解析游标
Cursor cursor = dbHelper.query(TabOther);
CoordinateAlterSample persion = null;
if (cursor.moveToFirst()) {
while (!cursor.isAfterLast()) {
persion = new CoordinateAlterSample();
persion.id = cursor.getString(cursor.getColumnIndex("id"));
persion.name = cursor.getString(cursor.getColumnIndex("name"));
rst.add(persion);
cursor.moveToNext();
}
}
return rst;
}
//修改