Breadline は違う意味です。パン屋さんに関係ありません。
英語では「パン屋さん」は「bakery」になります。なので、「学校にあるパン屋さん」は the school bakery や the bakery at school に相当します。
例文
A: Where did you get that bread? It looks delicious.
そのパンはどこで買ったの？美味しそう。
B: I bought it at the bakery at school. It was only 100 yen,
学校にあるパン屋さんで買ったんですよ。100円だけかかりました。
ご参考までに。
"School bakery" Is the term used to describe a bakery within a school, ex. "We have a bakery at our school"
"I'm going to get a sandwich at the school bakery"
学校の中にあるパン屋のことは "School bakery" と言えます。
例えば：
"We have a bakery at our school"（私たちの学校にはパン屋があります）
"I'm going to get a sandwich at the school bakery"（学校のパン屋でサンドイッチを買います）
We can buy delicious baked treats from the bakery.
Public schools don't usually don't have bakeries but they do have a tuckshop where they can buy snacks and light food.
We can use the above expressions when we go to a school with a bakery.
We have a school bakery within the school premises.
We have a bakery solely for the school within the school premises.
If the bakery serves the school only, it can be called a 'dedicated school bakery'. It can also be simply called a 'school bakery'. However, the location of the bakery must also be mentioned for it to be identilfied as a 'school bakery'. In this case, the bakery's location is within (inside) the school 'premises'. The noun 'school premises' means the school buildings and the land on which the buildings stand. This may be an area inside a fence. The adverb 'solely' used in the third statement means 'specifically for'or 'only' for the school.
So, you may say to someone:
We have a dedicated school bakery at school.
or
We have a school bakery within the school premises.
or
We have a bakery solely for the school within the school premises.
そのパン屋がある学校専用のものであるなら、それは 'dedicated school bakery' と言えます。あるいはシンプルに 'school bakery' と言うこともできます。
ただ、パン屋の場所についても伝える必要があります。この場合は、パン屋は学校の敷地内にあるわけです。'school premises' は、学校とその土地を指します。これはフェンスで囲まれていることもあります。
三つ目の例の 'solely' は、「（その学校）専用の」という意味です。
次のように言うことができます。
We have a dedicated school bakery at school.
（学校に専用のパン屋があります）
We have a school bakery within the school premises.
（校内にパン屋があります）
We have a bakery solely for the school within the school premises.
（校内に専用のパン屋があります）
If you have a bakery at school, it would probably be referred to as a 'school bakery'. However, that would be quite unusual. In the normal case, a school would have a kitchen, or more precisely, 'an industrial kitchen' if it is a big school, and all cooking, baking and food preparation would take place in this location.
"We have our own bakery at school."
もし学校にパン屋があるなら、おそらくそれは 'a school bakery' と呼ばれるでしょう。しかし、これはかなり珍しいです。普通、学校には 'a kitchen'（あるいはもしそれが大きな学校でベーキングを含めあらゆる調理が行われるということなら、'an industrial kitchen'）があります。
"We have our own bakery at school."（私たちの学校にはパン屋があります）
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