Question: “What did The Buddha realize the night he attained enlightenment under the Bodi tree. Was it paticcasamuppada or the four noble truths? What is Idapaccayata?”
The Buddha wanted to know how to get out of the cycle of suffering, he wanted to know how to end it. He had a lavish lifestyle growing up as a prince and still saw suffering, and then tried extreme asceticism and still could not find the answer to his question. Then he realized the Middle Way. When he gained Enlightenment, he gained the knowledge of the Four Noble Truths; the means of ending suffering, and from it the Eightfold Path; the path to ending suffering.
Buddha preached about Pratītyasamutpāda (dependent origination) later on when he turned the Dharma Wheel.
Idapaccayatā can roughly be translated as the conditioned nature of things, or the universal principle of conditionality. Basically the cause and effect of things. It refers to the principal of causality–that all things arise and exist due to certain causes (or conditions), and cease once these causes (or conditions) are removed.
This is, because that is.
This is not, because that is not.
This ceases to be, because that ceases to be.
Smile and be well!