[英]how to update column with type 'double' in database?
我一直在尝试更新其中存储双倍数据类型的一列,但它失败了,没有任何错误,我不知道我做错了什么
我尝试使用 ContentValues 使用 rawquery 和 update 但两者都不起作用,我知道它与 sqlite 中的 REAL 数据类型有关,但我不知道如何使其工作
我的桌子
private static final String SQL_CREATE_TABLE_WOUND
= "CREATE TABLE "
+ WOUND_TABLE_NAME + "("
//+ WOUND_ID + " TEXT,"
+ WOUND_POSITION + " INT,"
+ WOUND_SIZE + " DOUBLE,"
+ WOUND_OWNER + " TEXT,"
+ WOUND_PHOTO + " TEXT,"
+ WOUND_THUMBNAIL + " TEXT,"
+ WOUND_TREATED + " INT DEFAULT 0,"
+ WOUND_NUMBER + " INT,"
+ WOUND_DATE + " INT,"
+" FOREIGN KEY ("+WOUND_OWNER+") REFERENCES "+PATIENT_TABLE_NAME+"("+PATIENT_ID+"),"
+" FOREIGN KEY ("+WOUND_POSITION+") REFERENCES "+WOUND_POSITION_TABLE_NAME+"("+POSITION_NUMBER+"),"
+" PRIMARY KEY ("+ WOUND_OWNER +", "+ WOUND_POSITION +", "+ WOUND_NUMBER +", "+ WOUND_DATE +")"
+ ")";
这是我的更新功能
public boolean setWoundSizeValue(String ownerID,String position,String number,long date,Double value){
boolean setSuccess = false;
/*approach 2
ContentValues cv = new ContentValues();
cv.put(WOUND_SIZE,value);*/
SQLiteDatabase db = this.getWritableDatabase();
/*approach 1, didn't work
try{
String strSQL = "UPDATE "+WOUND_TABLE_NAME+" SET "+WOUND_SIZE+" = "+value+" WHERE "+WOUND_OWNER+" = "+ownerID+" AND "
+ WOUND_POSITION+" = "+position+ " AND "+ WOUND_NUMBER +" = "+ number +" AND "+WOUND_DATE +" = "+date;
Cursor c = db.rawQuery(strSQL,null);
if(c!=null){
if(c.moveToFirst()){
setSuccess = true;
}
c.close();
}
}catch (Exception e){
}*/
/*approach 2 didn't work
long result = db.update(WOUND_TABLE_NAME,cv,WOUND_OWNER+"=? AND "+ WOUND_POSITION+"=? AND "+ WOUND_NUMBER +"=? AND "+WOUND_DATE+"=?"
,new String[]{ownerID,position,number,String.valueOf(date)});
if(result>0){
setSuccess = true;
}*/
return setSuccess;
}
这就是我调用更新函数的地方
public class SetWoundSizeActivity extends AppCompatActivity {
private EditText setWoundSize;
private Button saveButton;
private String owner;
private String position;
private String woundNum;
private String timer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_set_wound_size);
getSupportActionBar().setTitle("Set Wound Size");
Intent intent = getIntent();
owner = intent.getStringExtra("owner");
position = intent.getStringExtra("position");
woundNum = intent.getStringExtra("woundNum");
timer = intent.getStringExtra("timer");
setWoundSize = findViewById(R.id.wound_size);
saveButton = findViewById(R.id.wound_size_button);
saveButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
DatabaseHelper helper = new DatabaseHelper(SetWoundSizeActivity.this);
SQLiteDatabase db = helper.getWritableDatabase();
final double woundSize = Double.valueOf(setWoundSize.getText().toString());
Toast.makeText(SetWoundSizeActivity.this,"size is"+woundSize,Toast.LENGTH_LONG).show();
//String ownerID,String position,String number,long date,float value
boolean result;
result = helper.setWoundSizeValue(owner,position,woundNum,Long.valueOf(timer),woundSize);
if(result){
Toast.makeText(SetWoundSizeActivity.this,"size inserted",Toast.LENGTH_LONG).show();
}else{Toast.makeText(SetWoundSizeActivity.this,"size not inserted",Toast.LENGTH_LONG).show();}
finish();
}
});
}
}
没有错误,但在我调用它的地方确认的结果总是错误的
rawQuery()
不能确定工作,因为它仅用于以Cursor
的形式获取数据。
但是带有ContentValues
update()
确实有效,这是推荐的方法:
ContentValues cv = new ContentValues();
cv.put(WOUND_SIZE, value);
int rows = db.update(
WOUND_TABLE_NAME,
cv,
WOUND_OWNER + " = ? AND " + WOUND_POSITION + " = ? AND " + WOUND_NUMBER + " = ? AND " + WOUND_DATE + " = ?",
new String[] {ownerID, position, number, String.valueOf(date)}
);
在变量rows
中将返回更新的行数。
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