Error reporting and recovery in Sangrah

• Published in: Software: Practice and Experience
• Main Authors: Prakash, Naveen, Gejji, P. N.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1981
• Subjects: DML
• Online Access: http://dx.doi.org/10.1002/spe.4380110605; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fspe.4380110605; https://onlinelibrary.wiley.com/doi/pdf/10.1002/spe.4380110605

Abstract In Sangrah, exception conditions of CODASYL have been replaced by fatal errors and by boolean valued functions. Fatal errors can occur either because all the preconditions necessary for a DML statement are not fulfilled or because of the state of the data base at the time when this statement is executed. A mechanism which anticipates the former situation and thereby saves the data base from corruption is presented. Another recovery scheme which protects the data base from an abnormal termination of the user program is also described. This scheme uses a differential file.