Optional (numeric) attributes without default value in Core Data - why are they discouraged?

可选的（数字）的属性没有默认值的核心数据-他们为什么沮丧？

youdao

After they went up to the Valley of Eshcol and viewed the land, they discouraged the Israelites from entering the land the LORD had given them.

他们上以实各谷，去窥探那地回来的时候，使以色列人灰心丧胆，不进入耶和华所赐给他们的地。

youdao

But children are frequently discouraged from involvement with natural spaces, for health and safety reasons, for fear that they might get dirty or that they might cause damage.

但出于健康和安全方面的考虑，担心它们会弄脏或造成损害，孩子们经常被劝阻不要接触自然空间。

youdao

Forty percent said they were discouraged from pursuing their chosen career, typically in college and often by their professors, an experience Jemison remembers from her undergraduate days.

VOA: standard.2010.03.26

If Korean students are having trouble with articles, I really recommend they don't get discouraged.

如果韩国学生学习冠词有问题的话，我真地建议他们不要气馁。

韩国人经常犯的失误 - SpeakingMax英语口语达人

Dr.Vallenas says many mothers are discouraged from breast-feeding because they do not know how to get their baby to latch on properly to the breast's nipple, or because they suffer pain and discomfort.

VOA: standard.2009.08.01

He saw a lot of more talented pilots fall out of the training program because they became discouraged at all of the criticism they had to endure.

FORBES: Robert Greene: How to Become the Master of Any Skill

The very fact that they get discouraged is what prevents them from getting rich.

FORBES: Acres Of Diamonds Occupy Wall Street

They were discouraged from consuming more than two tablespoons of vegetable oils, including olive oil, each day.

CNN: Mediterranean diet lowers risk of heart attack, stroke