如何在SQLite中插入和检索数据？
如何在SQLite中插入和检索数据？
提问于 2019-03-31 23:38:07
我已经写了一个应用程序，我必须将其数据插入到sqlite数据库中，并在一个活动中显示它。但是我的代码显示“没有找到记录”，即使我已经插入了它。
我尝试过使用不同的选项，比如先将光标移动到第一个记录，然后在记录上使用循环迭代。
将数据插入到数据库中
private void saveToDB() {
SQLiteDatabase database = new ChildMonitoringAppDBHelper(this).getWritableDatabase();
ContentValues values = new ContentValues();
values.put(ChildMonitoringAppDBHelper.CHILD_NAME, name.getText().toString());
values.put(ChildMonitoringAppDBHelper.CHILD_AGE, age.getText().toString());
values.put(ChildMonitoringAppDBHelper.CHILD_DOB, dob.getText().toString());
values.put(ChildMonitoringAppDBHelper.CHILD_HEIGHT, height.getText().toString());
values.put(ChildMonitoringAppDBHelper.CHILD_WEIGHT, weight.getText().toString());
database.insert(ChildMonitoringAppDBHelper.CHILD_TABLE_NAME, null, values);
database.close();
}从数据库中检索数据
public ArrayList<Child> readFromDB()
{
ArrayList<Child> List = new ArrayList<>();
SQLiteDatabase database = new ChildMonitoringAppDBHelper(this).getReadableDatabase();
Cursor cursor = database.rawQuery("select * from " + ChildMonitoringAppDBHelper.CHILD_TABLE_NAME, null);
cursor.moveToFirst();
while(!cursor.isAfterLast())
{
Child child = new Child(cursor.getString(cursor.getColumnIndex("CHILD_NAME")), cursor.getString(cursor.getColumnIndex("CHILD_AGE")), cursor.getString(cursor.getColumnIndex("CHILD_DOB")), cursor.getString(cursor.getColumnIndex("CHILD_HEIGHT")), cursor.getString(cursor.getColumnIndex("CHILD_WEIGHT")));
List.add(child);
cursor.moveToNext();
}
cursor.close();
return List;
}它应该显示输入的记录，但它正在制作吐司"No record found“。
回答 2
Stack Overflow用户
发布于 2019-03-31 23:48:50
Cursor cursor = database.rawQuery("select * from " + ChildMonitoringAppDBHelper.CHILD_TABLE_NAME, null);
if (cursor.moveToFirst())
{
do {
Child child = new Child(cursor.getString(cursor.getColumnIndex("CHILD_NAME")), cursor.getString(cursor.getColumnIndex("CHILD_AGE")), cursor.getString(cursor.getColumnIndex("CHILD_DOB")), cursor.getString(cursor.getColumnIndex("CHILD_HEIGHT")), cursor.getString(cursor.getColumnIndex("CHILD_WEIGHT")));
List.add(child);
} while (cursor.moveToNext());
}
cursor.close();
return List;你能不能试一下这段代码，看看它是否对你有用？
Stack Overflow用户
发布于 2019-03-31 23:58:30
public ArrayList<Child> readFromDB()
{
List list = new ArrayList<Child>();
Cursor cursor = database.rawQuery("select * from " +
ChildMonitoringAppDBHelper.CHILD_TABLE_NAME, null);
SQLiteDatabase database = this.getWritableDatabase();
Cursor cursor = database.rawQuery(selectQuery, null);
if (cursor.moveToFirst())
{
do
{
Child child = new Child(cursor.getString(cursor.getColumnIndex("CHILD_NAME")),
cursor.getString(cursor.getColumnIndex("CHILD_AGE")),
cursor.getString(cursor.getColumnIndex("CHILD_DOB")),
cursor.getString(cursor.getColumnIndex("CHILD_HEIGHT")),
cursor.getString(cursor.getColumnIndex("CHILD_WEIGHT")));
list.add(child);
}
while (cursor.moveToNext());
}
cursor.close();
// return list of inserted values
return list;
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/55442545
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