Lecture
Work with raBD is provided by distributed DBMS. RDBMS is a set of programs designed to manage a distributed database and allows you to make the distribution of information “transparent” to the end user. Components of RDBMS: - workstations (nodes); - network equipment and software; - communication equipment; - transaction manager; - data manager; - scheduler. Basics Holy Island DBMS:
1. The transparency of the location is given.
2. The heterogeneity of the system
3. Network Transparency
4. Support Responsive Queries, Changes, Transactions
5. Security
6. Universality of access.
The reasons for the inefficiency of the RDBMS:
1. Reduced processing performance;
2. Long-term blocking of changeable data during the execution of distribution transactions;
3. The compatibility is given;
4. Selecting the layout. system directories;
5. Provide. combining DBMS of different types and suppliers;
6. Increase consumers in resouras. There must be at least one global application in a RDBMS, so any RDBMS must have the following features:
1. a set of logically related shared data;
2. the stored data is divided into a number of fragments;
3. between fragments can be organized data replication;
4. fragments and their replicas are distributed among different nodes;
5. nodes are interconnected by network connections;
6. work with data on each node is controlled by a local DBMS. The DBMS at each node is able to support the autonomous operation of local applications.
12 rules of C. Data
The basis of these rules is that RABD should be perceived by the user in the same way as the usual centralized database.
1. Local autonomy. local data belong to local owners; all local processes remain purely local; all processes on a given node are controlled only by that node.
2. Lack of support on the central node. The system should not have a single node, without which the system can not function.
3. Continuous operation. Ideally, the system should not need to stop its operation.
4. Independence from location. The user must access the database from any node, and to gain access to any data, no matter where they are physically stored.
5. Independence from fragmentation. The user must access the data regardless of how it is fragmented.
6. Independence from replication. The user will not have the means to obtain direct access to a specific copy of the data element, and should not care about updating an existing copy.
7. Processing distributed requests. The system must support the processing of queries that refer to data located on more than one node.
9. Independence from the type of equipment. The system must be able to operate on equipment with various computing platforms.
10. Independence from network architecture.
11. Independence from the operating system.
12. Independence from the type of DBMS.
Advantages of RDBMS:
1. Reflection of the structure of the organization.
2. Separability and local autonomy.
3. Increase data availability.
4. Increased reliability.
5. Increased productivity.
6. Economic benefits.
7. Modularity of the system.
Disadvantages of RDBMS:
1. Increasing the complexity of the RDBMS itself.
2. The increase in the cost of the acquisition and maintenance of RDSUBD.
3. Problems of protection of D, network connections, access control to D.
4. Complicating data integrity monitoring.
5. Lack of standards.
6. Lack of experience with distributed systems
7. Complication of the database development procedure.
8. The complexity of management.
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Databases, knowledge and data warehousing. Big data, DBMS and SQL and noSQL
Terms: Databases, knowledge and data warehousing. Big data, DBMS and SQL and noSQL