ACID Properties To preserve integrity of data, the database system must ensure Atomicity. Either all operations of the transaction are properly reflected in the database or none are Consistency. EXecution of a transaction in isolation preserves the consistency of the database Isolation. Although multiple transactions may execute concurrently, each transaction must be unaware of other concurrently executing transactions. Intermediate transaction results must be hidden from other concurrently executed transactions t That is, for every pair of transactions T; and T, it appears to Ti that either Ti, finished execution before Ti started, or Ti started execution after T finished Durability. After a transaction completes successfully, the changes it has made to the database persist, even if there are system failures Database System Concepts 15.3 OSilberschatz. Korth and SudarshanDatabase System Concepts 15.3 ©Silberschatz, Korth and Sudarshan ACID Properties Atomicity. Either all operations of the transaction are properly reflected in the database or none are. Consistency. Execution of a transaction in isolation preserves the consistency of the database. Isolation. Although multiple transactions may execute concurrently, each transaction must be unaware of other concurrently executing transactions. Intermediate transaction results must be hidden from other concurrently executed transactions.  That is, for every pair of transactions Ti and Tj , it appears to Ti that either Tj , finished execution before Ti started, or Tj started execution after Ti finished. Durability. After a transaction completes successfully, the changes it has made to the database persist, even if there are system failures. To preserve integrity of data, the database system must ensure: