1. A method for modifying data contained in a database; wherein such method comprises a plurality of steps intended to modify the data forms a transaction; wherein said transaction comprises statements that operate within the database, of which statements at least one statement is arranged to transmit information between that statement and another statement, and parameters both regarding the statements and regarding the transaction; wherein at least one statement of the transaction contains a logical operation in order to check the transaction's validity, whereby the information about the result of said logical operation after its performance is added to the common information exchange space of the transaction.