Modeling of the decision-supporting process on the possibility of concluding the contract on the therapeutic services provision. РОЗВИТОК АРХІТЕКТУР, ТЕОРЕМ ТА МОДЕЛЕЙ ВЛАСТИВОСТЕЙ РОЗПОДІЛЕНИХ СИСТЕМ ЗБЕРІГАННЯ ІНФОРМАЦІЇ

Today, we live in the world of information technologies, which have penetrated into all possible spheres of human activity. Recent developments in database management systems have coincided with advances in parallel computing technologies. In view of this fact, a new class of data storage has appeared, namely globally distributed non-relational database management systems, and they are now widely used in Twitter, Facebook, Google and other modern distributed information systems to store and process huge volumes of data. Databases have undergone a certain evolution from mainframe architecture to globally distributed non-relational repositories designed to store huge amounts of information and serve millions of users. The article indicates the drivers and prerequisites of this development, and also considers the transformation of models of properties of database management systems and theorems that formalize the relationship between them. In particular, the conditionality of the transition from the ACID property model to the BASE model is considered, which relaxes the requirements for data consistency, which is necessary to ensure the high performance of distributed databases with many replicas. In addition, a concise justification of the SAR and PACELC theorems, which establish mutually exclusive relationships between availability, consistency, and speed in replicated information systems, is provided, and their limitations are analyzed. The compatibility issues of the consistency models used by different non-relational data stores are noted, and, as an example, the possible consistency settings of the NoSQL databases Cassandra, MongoDB, and Azure CosmosDB are discussed in detail. The results of the evolution of distributed database architectures are summarized using the GSN (Goal Structuring Notation). Further directions of scientific research and ways of further developing globally distributed information systems and data repositories are also outlined.