Hospital or healthcare database is used to healthcare systems for Data management for resources, patient, doctors, medicine, labs, clinic, etc. Task.2 evaluation of Database features Relational keys There are two kinds of keys in relations. Primary key is the main concept, while two other keys super key and candidate key foreign key identity keys: Super keys: it is a set of field whose values can be uniquely identify a tuple within a table. More than one super key can have in a relation, but it always has at least one set of attributes that make up the relation. Candidate keys: It is a super key that is minimal A relation can have more than one candidate key, and the different candidate keys may have a different number of attributes. Primary key: it is a relation is a candidate key to uniquely identify a record. In other words, only one candidate key designated to be the primary key.
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Providing isolation is the best main goal of concurrency control. Depending on concurrency control method, the effects of an incomplete transaction might not even be visible to another transaction. Durability durability means that once a transaction has been committed, it will remain so, even in the event of power loss, crashes, or errors. In a relational database, for instance, once a group of sql statements execute, the results need to be stored permanently (even if the database crashes immediately thereafter). To defend against power loss, transactions (or their effects) must be recorded in a non-volatile memory. Task.1 Application of Database banking Managing Customer data and financial Transaction Retail to achieve the near real-time data availability and to reap the fruits of near real-time data in the retail-value chain. Database is used for maintaining all the data and information about all the process flow of Retail System. Human Resource database is used to maintain all the record of employee and company resources, job and Resume details, company department and Office details like address, regions, and countries. Human Resource management System also maintain information about history of employees, Ex-employees and all other hrms relation business process information. Hrms is a pure database management Domain. Transport Domain Database is used in Transport System to maintain daily Travel service, customer information, booking related information, including payment, order and marketing.
The potential passenger must either: both pay for front and reserve a seat; or neither pays for nor reserves a seat. The booking system does not consider it acceptable for a customer to pay for a ticket without securing the seat, nor to reserve the seat without payment succeeding. Consistency This ensures that any transaction will bring the database from one valid state to another. Any data written to the database must be valid according to all defined rules, including but not limited to constraints, cascades, triggers, and any combination thereof. This does not guarantee correctness of the transaction in all ways the application programmer might have wanted as it is the responsibility of application-level code but merely that any programming errors do not violate any defined rules. Data consistency means that each user sees a consistent view of the data, including visible changes made by the users own transactions and transactions of other users. Example of Consistency ( Transactions and read Consistency ) Database provides statement-level read consistency using data in rollback segments. Isolation It ensures that the concurrent execution of transactions results in a system state that would be obtained if transactions were executed serially.
Three classic problems PB: two (more) transactions read / write on the same part of the. Although transactions execute correctly, results may interleave in different ways 3 classic problems Lost Update Uncommitted Dependency Inconsistent Analysis Example of concurrency best Example of Data concurrency is Ticket booking transaction Atomicity It is part of Database Transaction acid property which guarantees reliability. Atomicity requires that each transaction is all or nothing: if one part of the transaction fails, the entire transaction fails, and the database state is left unchanged. An atomic system must guarantee atomicity in each and every situation, including power failures, errors, and crashes. To the outside world, a committed transaction appears to be indivisible (atomic) and an aborted transaction does not happen. A guarantee of atomicity prevents updates to the database occurring only partially, which can cause greater problems than rejecting the whole series outright. Atomicity means indivisibility and irreducibility. Example of atomicity is ordering an airline ticket where two actions are required: payment, and a seat reservation.
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Using deferred update, writes are done initially to the log only and log records are used to perform actual updates to the database. If the system fails, it examines the log to determine which transactions for it needs to redo, but there is no need to undo any writes. Using immediate updates, an update may be made to the database itself any time after a long record is written. The log can be used to undo and redo transactions in the event of failure. (greenyer, andrew, 2007) Example recovery Application The Active/Passive pattern is the choice that many companies favor.
This pattern provides improvements to the rto with a relatively small increase in cost over the redeploy pattern. In this scenario, there is again a primary and a secondary data center. All of the traffic goes to the active deployment on the primary data center. The secondary data center is better prepared for disaster recovery because where the database is running on both data centers. Concurrency many database transactions at the same time and Databases shared is called as Database concurrency In Database concurrency Transactions must be isolated need of concurrency control to ensure no interference.
Database uses schemas and security domains to control access to data and to restrict the use of various database resources by any user. Database access control regulates all user access to named objects through privileges. A privilege is permission to access a named object in a prescribed manner;. For example, permission to sql queries a table. Privileges are granted (i.e.
Grant permission) to users at the discretion of other users. Database security rules that protect the database against intentional or accidental threats. Database security avoiding the following situations: Theft and fraud Loss of confidentiality loss of privacy loss of integrity loss of availability computing based security controls for multi-user environment as follow Authorization views Backup and recovery Integrity Encryption raid technology Application of Data security Above diagram. Encrypted data is transparently decrypted for a database user who has access to the data. Transparent data encryption helps protect data stored on media in the event that the storage media or data file gets stolen or theft. Learn about Computing and System development Assignment Recovery restoring database to a correct state of data in case of failure is called as Recovery of database. Recovery technique maintain a log file containing transactions records that identify the start/end of transactions and the before-and after-images of the write operation.
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Foreign keys must be Primary keys and therefore non-null) Example of Data Integrity Example shows tables dept and emp: Table dept (deptno, dname, loc) dname column must having unique value. Table emp(empno, ename, sal, comm, deptno) Column ename must have value in each row. Column empno must have unique value in each row. Each value in the deptno column must match a value in the deptno column of the dept table. Sal column value must be lower than 10,000. Data redundancy The repetition of data in the data is known as data redundancy. Same data in more than one field or table of data, or including a data as a separate. This resumes repetition of the data can cause some anomalies and distortions results. (smalltree, essay hannah, 2007) Example of Data redundancy data security db-threats Database security is to allowing or disallowing user actions on the database and the objects.
Types of funniest Data Integrity, the rules that can be applied to table columns to enforce different types of data integrity. Null Rule: this rule defined on a column of table that allows or disallows inserts/updates of rows having a null as value (in case of empty value) in that column. Unique column Values: this rule defines on a column (or group of columns) it allows the insert or update of a row only if it contains a unique value in that column (or group of columns). Primary key values: this defined on a key (a column or group of columns) specifies that each row in the table can be uniquely identified by the values in the key (a column or group of columns). Integrity rules, domain Rules: give correct values for domains. Attribute rules: give correct values for attributes. Relation Rules: governing single relations (i.e. Primary keys must be unique and Non-null) Database rules: governing interrelationships between relations (i.e.
true or must always be false. Data Integrity technique, designing database application requires guarantee integrity of data stored. Below are the data Integrity techniques. Applying business rules with triggered stored database procedures in database. Stored procedures used to completely control access to data. Applying business rules in the code of a database application. Using Database integrity constraints, which are rules defined at the column or object level to restrict values in the database.
Distributed database is a database in which data is stored in storage devices that are located in distributed physical location but its controlled using a central. In a centralized database, all dillard the data of an organization is stored in one location such as a mainframe computer or a server. It is accessible by remote user through the. Wide Area network (WAN) using the application programs or system provided to access the data. The centralized database. Able to handle all the requests coming to the system, since all the data reside in a single place it easier to maintain and back up data and it is easier to maintain data integrity. Example: Major disadvantages of this type of Database solution: Network requirements, single point of failure, server Scalability.
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Database Analysis mother and Design Assignment 08-04-16, rochio varela 3 comments, database Analysis and Design Assignment development is fundamental in the area of software development, database management Systems provide the systems, tools and interfaces by which handles the storage, retrieval, and updating of data. Databases offer many features in areas such as programming, systems analysis, etc. In this report database architecture, dbms and the use of databases in an organizational context is explored. Database design techniques are investigated and will be able to apply theoretical understanding to design, create and document a database system. This report includes the answer of all tasks of Database management Topics and Case Study implementation. Structured Systems Analysis and Design Method (ssadm). Task 1 database Analysis and Design Assignment Management Systems. Task.1 key issues of Database. Centralized control of data, data stored and maintained in a single location is Centralized database.