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CUSTOMER_CODE SMUDE DIVISION_CODE SMUDE EVENT_CODE APR2016 ASSESSMENT_CODE BC0050_APR2016 QUESTION_TYPE DESCRIPTIVE_QUESTION QUESTION_ID 4175 QUESTION_TEXT Explain the different modes of shutting down process in database. SCHEME OF EVALUATION The syntax of the SHUT DOWN command is SHUT DOWN [NORMAL|IMMEDIATE|TRANSACTIONAL|ABORT] NORMAL: This is default mode for shutting down the database. The oracle server waits for all currently connected users to disconnected users to disconnect their sessions. No new connections are permitted. A checkpoint is performed on the entire database and the files are closed. When a database is shutdown in this mode an instance recovery will not need to be done during the subsequent startup. (2.5 marks) IMMEDIATE: when a database is shutdown in this mode. The oracle server automatically rolls back all currently active transactions. After the transactions have been rolled back the user sessions are terminated. No new connections are allowed. The database is then closed, dismounted and the instance released. No instance recovery will be performed during subsequent startup. (2.5 marks) TRANSACTIONAL: when the database is shutdown using this option, all currently active transactions completes the user is automatically dismounted. No new user connections will be allowed. The database is then closed dismounted and the instance released. No instance recovery will be performed during subsequent startup. (2.5 marks) ABORT: When the database is shutdown using this option, the instance is shutdown. This is a case of an improper shutdown. No check pointing is done. All user connections are abnormally terminated. The database is not closed or dismounted. (2.5 marks) Total 10 marks QUESTION_TYPE DESCRIPTIVE_QUESTION QUESTION_ID 4179 QUESTION_TEXT Explain any FIVE features of Heterogeneous Services agent 1.Distributed transactions 2.Transparent SQL access SCHEME OF EVALUATION 3.Procedural access 4.Data dictionary translations 5.Pass-through SQL 6.Accessing stored procedures 7.National language support 8.Multi-threaded agents 9.Agent self-registration 10.Management interface (Any FIVE from the above which carries 2 marks each) QUESTION_TYPE DESCRIPTIVE_QUESTION QUESTION_ID 72868 QUESTION_TEXT Explain any 4 physical files of the database. SCHEME OF EVALUATION Datafiles Control files Parameter file Archive file (Each with Explanation 2.5*4) QUESTION_TYPE DESCRIPTIVE_QUESTION QUESTION_ID 113960 Give the description of the following 5 characteristics of query processors: QUESTION_TEXT a. Languages b. Types of optimization c. Optimization timing d. e. a. b. SCHEME OF EVALUATION Statistics Decision sites Languages: The input language to the query processor can be based on relational calculus or relational algebra. In distributed context, the output language is generally some form of relational algebra augmented with communication primitives. Types of Optimization: Conceptually, query optimization is to choose a best point of solution space that leads to the minimum cost. A popular approach called exhaustive search is used. This is a method where heuristic techniques are used. In both centralized and distributed systems a common heuristic is to minimize the size of intermediate relations. Performing unary operations first and ordering the binary operations by the increasing size of their intermediate relations can do this. c. d. e. Optimization Timing: A query may be optimized at different times relative to the actual time of query execution. Optimization can be done statically before executing the query or dynamically as the query is executed. The main advantage of the later method is that the actual sizes of the intermediate relations are available to the query processor, thereby minimizing the probability of a bad choice. Statistics: The effectiveness of the query optimization is based on statistics on the database. Dynamic query optimization requires statistics in order to choose the operation that has to be done first. Static query optimization requires statistics to estimate the size of intermediate relations. The accuracy of the statistics can be improved by periodical updating. Decision Sites: Most of the systems use centralized decision approach, in which a single site generates the strategy. However, the decision process could be distributed among various sites participating in the elaboration of the best strategy. The centralized approach is simpler but requires the knowledge of the complete distributed database where as the distributed approach requires only local information. (2 marks each) QUESTION_TYPE DESCRIPTIVE_QUESTION QUESTION_ID 113966 Briefly explain the properties of Transaction application QUESTION_TEXT a. i. ii. SCHEME OF EVALUATION b. c. d. Atomicity (2 marks) Transaction aborts System crashes (1 mark each) Durability (2 marks) Serializability (2 marks) Isolation (2 marks) QUESTION_TYPE DESCRIPTIVE_QUESTION QUESTION_ID 113967 QUESTION_TEXT Explain the notions of Transparency and Site autonomy Transparency: (5 marks) SCHEME OF EVALUATION a. Location transparency b. Replication transparency Site autonomy (5 marks)