As modern computing has evolved toward global distributed architectures, consistency maintenance across diverse data has become a fundamentally different challenge. The ACID properties of traditional transactional models do not meet the availability and performance requirements of large distributed integration systems. The transition from strong consistency to eventual consistency model is the subject of this report. The paper explores the theoretical underpinnings of the CAP and PACELC theorems, which depict the fundamental trade-offs between consistency, availability, and latency in the presence of network partitions. The technical mechanisms through which states converge are the focus of this discussion. The three important mechanisms that help achieve states converge are anti-entropy gossip protocols, logical vector clocks, and Conflict-Free Replicated Data Types (CRDTs). Moreover, the analysis studies enterprise integration patterns i.e. EDA and Saga patterns that enable long-running transactions without the need for global locking. The difficulties of heterogeneous data integration, particularly the structural and semantic variations in data, are also addressed in the research. The paper concludes that although eventual consistency may add architectural complexity, academic research and industrial implementations have demonstrated that it can be a viable solution for data integrity in distributed systems with high availability.