Dtjytyk

If I make a sentence like:

Das ist meine Familie.

Is the sentence correct at first place? Is it a nominative case for Familie or is it accusative? It looks confusing to me because here the subject of the sentence comes after the ist so I am not sure about which case applies here. Generally, I find it difficult to determine the grammatical case when the verbs are sein and haben.

Some verbs can be used as couplers (they are called copula in linguistic terms). In a narrow sense these are sein, werden, and bleiben. These verbs take a Prädikativ, which may be an "object" in the nominative case.

Das ist meine Familie.

Er wird nochmal Vater.

Ein Fehler bleibt ein Fehler.

The other common option is an adjective phrase as in

Diese Übung war recht einfach.

Other verbs may be sometimes used as couplers, too. For example

Er gilt als begabter Koch.

Diese Sache erweist sich als Glücksfall.

Du siehst in diesen Sachen aus wie deine Oma.

and some more. You can often spot that use by the comparative conjunctions als and wie.

Yes, your sentence is correct. (apart from the capitalisation of "Familie")

"Something/someone is something/someone" the latter "something" can be considered an object in nominative, which is often called a "Subjektsprädikativ"

It is Nominativ - you can ask "wer?" (who) - Wer ist das? Das ist meine Familie.

If the sentence was "Ich sehe meine Familie", it would be Akkustaiv, for you could ask "wen sehe ich?" (whom do I see?).

Unfortunately for foreign learners of German, the "meine Familie" looks the same in both cases.

I agree with the other answers but I will try to explain why it is so confusing for English and French speakers.

1. English: We can't tell the difference between nominative and accusative at all for nouns and adjectives, so our understanding is based solely on pronoun examples. We are taught at school to say That's I "Das ist ich" but most people say That's me. We are taught that this is wrong (despite it being normal, and therefore right by definition according to some people) on the same grounds that "das is mich" would be wrong. However, although English is considered to be a Germanic language (and so should use the same rules as German) it is heavily influenced by French (see 2 below) and the Celtic languages (see 3 below), and these influences probably explain (in my opinion) why we normally say That's me.




2. French: Normally they distinguish nominative and accusative for pronouns, e.g. je "ich" versus me "mich" (or "mir") but in certain situations they use a special, caseless form moi "ich/mich/mir" so when they say C'est moi you cannot tell what case the moi is and it does look more like "mich" than "ich". It is easy to see how C'est moi could have become It's me in English.




3. The various Celtic languages use cases to varying degrees, but what they all have in common is a complete lack of distinction between nominative and accusative, applying to nouns, adjectives and pronouns. Thus a Scots Gaelic speaker, for example, when first learning English, would be tempted to translate 'S mì as [It]'s me as it sounds almost the same even though mì corresponds to both "ich" and "mich".