Database transaction - Database transaction A database transaction is a unit of interaction with a Database management system or similar system that is treated in a coherent and reliable way independent of other transactions. Ideally, a database system will guarantee all of the ACID properties for each transaction. In practice, these properties are often relaxed somewhat to provide better performance. In database products the ability to handle transactions allows the user to ensure that integrity of a database is maintained. A single transaction might require several queries, each reading and/or writing information in the database. When this happens it is usually important to be sure that the database is not left with only some of the queries carried out. For example, when doing a money transfer, if the money.
Java Transaction API - Java Transaction API The Java Transaction API is one of the J2EE APIs allowing distributed transactions to be done across multiple XA resources. It provides for: demarcation of transaction boundaries X/Open XA API allowing resources to participate in transactions. Table of contents showTocToggle("show","hide") 1 X/Open XA architecture 2 JTA implementation of the X/Open XA Architecture 3 Examples 3.1 Transaction Management in a Simple Application 3.2 Transaction Management in an EJB 4 Additional Resources X/Open XA architecture In the X/Open XA architecture, a transaction manager or transaction processing monitor AKA TP monitor, coordinates the transactions across multiple resources such as a database. Each resource has its own manager. The resource manager typically has its own API for manipulating the resource, for example the JDBC API used by relational.
Database - Database A database is an information set with a regular structure that allows automated searches and updates. There are a wide variety of databases, from simple tables stored in a single file to very large databases with many millions of records, stored in rooms full of disk drives. Databases resembling modern versions were first developed in the 1960s. A pioneer in the field was Charles Bachman. One way of classifying databases is by the programming model associated with the database. Several models have been in wide use for some time. Historically, the hierarchical model was implemented first, then the network model, then the relational model and flat models reached their zeniths. Database models The flat (or table) model consists of a single, two-dimensional array of data.
Database management system - Database management system A database management system (DBMS) is a computer program (or more typically, a suite of them) designed to manage a database, a large set of structured data, and run operations on the data requested by numerous users. Typical examples of DBMS use include accounting, human resources and customer support systems. Originally found only in large companies with the computer hardware needed to support large data sets, DBMSs have more recently emerged as a fairly standard part of any company back office. DBMS's contrast with the more general concept of a database applications in that they are designed as the "engine" of a multi-user system. In order to fill this role, DBMSs are typically built around a private multitasking kernel with built-in networking support..
Database log - Database log In computer science, in the field of databases, a Database Log is a history of actions executed by a database management system. Physically, a log is a file of records stored in stable storage, designed to withstand crashes. Table of contents showTocToggle("show","hide") 1 Anatomy of a General Database Log 2 Types of Database Logs Records 3 Tables Anatomy of a General Database Log A database log record is made up of (FIXME: resource managers, xid not universal) Log Sequence Number: A unique id for a log record. With LSNs, logs can be recovered in constant time. Most logs' LSNs are assigned in monotonically increasing order, which is useful in recovery algorithms, like ARIES. Prev LSN: A link to the last log record. This implies.
Transaction processing - Transaction processing In computer science, a transaction is a group of logical operations that must all succeed or fail as a group. Systems dedicated to supporting such operations are known as transaction processing systems. As an example, consider a typical banking operation, moving $500 from your savings account to your checking account. This seems like a single operation to the user, but in fact consists of two: debiting the savings account by $500, and crediting the checking account by $500. Imagine what would happen if the debit operation succeeded and the credit did not, $500 would disappear. Transaction processing systems allow these two operations to be "grouped" into a single transaction, so these sorts of problems cannot occur. They do this by making copies of the.
Jim Gray - computer scientist who received the Turing Award in 1998 "for seminal contributions to database and transaction processing research and technical leadership in system implementation". Gray studied at the University of California, Berkeley, receiving his PhD in 1969. Gray worked as an industrial researcher and software designer at a number of industrial companies, including IBM, Tandem and DEC, and now works as a Distinguished Engineer for Microsoft Research. He has contributed to the building of several major database and transaction processing systems, including the ground-breaking System R while at IBM, as well as an extensive record of publication in academic journals. External Links Gray's Microsoft Research home page.
IMS - IMS IMS began as a hierarchical database designed by IBM for Rockwell for the Apollo program. It was used to track the bill of materials for the Saturn V. IMS is still running thirty five years later and over time has seen some interesting developments as IBM S/360 technology developed into the current z/OS operating system. There are three basic forms of hierarchical database. 1. Full Function databases Full function, which is basically the same Data Language/1 (DL/I) databases as developed for Apollo. Full function databases can have primary and secondary indexes and are accessed using DL/I calls from your application program. Full function databases can have a variety of access methods, although Hierarchical Direct (HDAM) and Hierarchical Indexed Direct (HIDAM) prevail. The other formats are Simple Hierarchical Indexed Sequential.
InterBase - InterBase InterBase is a database management system (DBMS) currently developed and marketed by Borland. InterBase is distinguished from other DBMSs by its small footprint, close to zero administration requirements, and multi-generational architecture. InterBase runs on the Linux, Microsoft Windows, and Solaris operating systems. History Jim Starkey was working at DEC on their Datatrive network database product when he came up with an idea for a new system to manage concurrent changes by many users. Now known as multi-generational or versioning systems, his idea would dramatically simplify the existing problems of locking which were proving to be a serious problem for the new relational database systems being developed at the time. He wanted to work on his idea at DEC, but at the time DEC had just started a.
Financial Crimes Enforcement Network - Crimes Enforcement Network (FinCEN) maintains a comprehensive database of financial records created in 1990 as an arm of the United States Department of the Treasury to combat money laundering. Their primary purpose is to gather information on the movement of large or suspicious amounts of money, and to increase the communication about that movement to various domestic and international law enforcement agencies, including the Bureau of Alcohol, Tobacco, and Firearms, the Drug Enforcement Administration, the Federal Bureau of Investigation, the Secret Service, the Internal Revenue Service, the Customs Service, and the U.S. Postal Inspection Service. All banks, casinos, brokerage firms, or financial institutions that transfer money must notify FinCEN of any cash transaction over $10,000 in value, as well as any other "suspicious" activity..
Electronic Data Interchange - may also be called a mapping but the term mapping is typically reserved for specific machine readable instuctions given to the translation software.) Larger companies have existing specification sheets and are usually unwilling to negotiate. Often in a large company these sheets will be written to be used by different branches or divisions and therefore will contain information not needed for a particular exchange. (Deviations from and clarification to the specification sheets should alway be obtained in writing.) Often missing from the specifications are real world descriptions of how the data should be interpreted. This is particularly important when specifying quantity. For example, suppose candy is packaged in a large box that contains 5 display boxes and each display box contains 24 boxes of candy packaged for the consumer. If an.
Durability (computer science) - successfully committed will survive permanently and will not be undone by system failure. For example, if a flight booking database system reports that a seat has successfully been booked, then the seat will remain booked even if the system crashes. Durability also guarantees that the system will not rollback the transaction because the seat was double-booked. (The system must check this before it acknowledges the seat has been booked) The only way a transaction can be undone after it has been committed is by a compensatory transaction. Durability is usually implemented by flushing the transaction's log records to disk before acknowledging commitment. In distributed transactions, all participating servers must acknowledge that they have stored all data and checked all consistency constraints before commit can be acknowledged. This is usually done by.
Digital Equipment Corporation - systems supported several operating system of the day, including DEC's RSTS system, their most important role was to run Bell Labs' new UNIX operating system that was being made available to educational institutions. These PDP-11 systems were destined to be the sandbox for a generation of computer scientists. The PDP-11 had a 64K address space. Most models had a paged architecture and memory protection features to allow timesharing, and could support split Instruction & Data architectures for an effective address size of 128K. In 1976 DEC decided to move to an entirely new 32-bit platform, which they referred to as the super-mini. They released this as the VAX 11/780 in 1978, and immediately took over the vast majority of the minicomputer market. Desperate attempts by competitors such as Data General (which.
Data warehouse - system used to store information regarding an organization's activities in a database. The database design favours reporting on and analysing the data in order to gain strategic information and to facilitate decision making. Data warehouses may hold large amounts of information, sometimes in smaller logical units called Data marts. Often the schemas of data marts are stored in what are known as "Star Schemas", or Dimensional Modeling form; however there is no industry standard requiring that the schemas of data marts be in any particular form. There is, in fact, some controversy about the most useful form of data mart schemas. Conventional database systems use highly normalized data formats so that they execute transactions and queries as fast as possible, in minimal time and space. Data Warehouses often use a more.
ACID - Atomicity, Consistency, Isolation, and Durability. They are considered to be the key transaction processing features of a database management system, or DBMS. Without them, the integrity of the database cannot be guaranteed. In the context of databases, a single logical operation on the data is called a transaction. A transfer of funds from one account to another is considered a transaction, for example, even though it might consist of multiple tasks (debiting one account and crediting another). The ACID properties guarantee that such transactions are processed reliably. Atomicity refers to the ability of the DBMS to guarantee that either all of the tasks of a transaction are performed or none of them are. The transfer of funds can be completed or it can fail for a multitude of reasons, but atomicity.
Tandem Computers - of fault tolerant computer systems, marketed to the growing number of transaction processing customers who used them for ATMss, banks, stock exchanges and other similar needs. Tandem systems used a number of redundant processors and storage devices to provide high-speed "failover" in the case of a hardware failure, an architecture that they called NonStop. Over the two decades from the 1970s into the mid-90s, Tandem systems evolved into software-only solutions running on other platforms. The company was eventually purchased by Compaq in 1997 in order to provide that company with more robust server offerings. Today their software is still known as NonStop, as a separate product line offered by Hewlett-Packard. History Tandem Computers was founded in 1974 by a group of engineers from Hewlett-Packard, led by James Treybig. Their business plan.
Adaptive Server Enterprise - (ASE) is Sybase Corporation's flagship relational database product. ASE is a direct descendant of Sybase SQL Server as it was a change in name only starting from version 11.5 in 1996. In 1998, ASE 11.9.2 was rolled out with support for row-level locking and distributed joins and improved SMP performance. ASE 12.0 was released in 1999 providing support for Java, high availability and distributed transaction management. In 2001, ASE 12.5 was released providing features such as dynamic memory allocation and support for XML and SSL among others..
Concurrency control - in the field of databases -- concurrency control is a method used to ensure that database transactions are executed in a safe manner (i.e., without data loss). Concurrency control is especially applicable to relational databases and database management systems, which must ensure that transactions are executed safely and that they follow the ACID rules. The DBMS must be able to ensure that only serializable, recoverable schedules are allowed, and that no actions of committed transactions are lost while undoing aborted transactions. Transaction ACID Rules Atomicity - either all or no operations are completed. (UNDO) Consistency - all transactions must leave the database in consistent state Isolation - transactions cannot interfere with each other Durability - successful transactions must persist through crashes (REDO) There are several methods for concurrency control, the majority.
Turing Award - libraries) 1968 Richard Hamming (numerical methods, automatic coding systems, error-detecting and error-correcting codes) 1969 Marvin Minsky 1970 James H. Wilkinson (numerical analysis, linear algebra, "backward" error analysis) 1971 John McCarthy (artificial intelligence) 1972 Edsger Dijkstra (the science and art of programming languages) 1973 Charles W. Bachman (database technology) 1974 Donald E. Knuth (analysis of algorithms and the design of programming languages) 1975 Allen Newell and Herbert A. Simon (artificial intelligence, the psychology of human cognition, list processing) 1976 Michael O. Rabin and Dana S. Scott (nondeterministic machines) 1977 John Backus (high-level programming systems, formal procedures for the specification of programming languages) 1978 Robert W. Floyd (methodologies for the creation of efficient and reliable software) 1979 Kenneth E. Iverson (programming languages and mathematical notation, implementation of interactive systems, educational uses of APL,.
Schedule (computer science) - schedule that is equivalent to a serial schedule. Given E, the order of D has been changed, but in the end, E gives the same result as D. Recoverable: Transactions commit only after all transactions whose changes they read commit. These schedules are recoverable. F is recoverable because T1 commits before T2, that makes the value read by T2 correct. Then T2 can commit itself. In F2, if T1 aborted, T2 has to abort because the value of A it read is incorrect. In both cases, the database is left in a consistent state. Unrecoverable: If a transaction T1 aborts, and a transaction T2 commits, but T2 relied on T1, we have an unrecoverable schedule. In this example, G is unrecoverable, because T2 read the value of A written by T1,.
