Database

qas: question: What does DBMS stand for?
answers: text: database management system

question: What is the purpose of a DBMS?
answers: text: to allow the definition, creation, querying, update, and administration of databases

question: How are DBMSs classified?
answers: text: according to the database model that they support

question: What is the most popular DBMS?
answers: text: SQL language

question: What does DBMS stand against?

question: What is a DBMS designed to avoid?

question: What is generally portable across different DBMSs?

question: What is the least popular DBMS?

question: When did popular database systems stop releasing updates?
context: A database management system (DBMS) is a computer software application that interacts with the user, other applications, and the database itself to capture and analyze data. A general-purpose DBMS is designed to allow the definition, creation, querying, update, and administration of databases. Well-known DBMSs include MySQL, PostgreSQL, Microsoft SQL Server, Oracle, Sybase, SAP HANA, and IBM DB2. A database is not generally portable across different DBMSs, but different DBMS can interoperate by using standards such as SQL and ODBC or JDBC to allow a single application to work with more than one DBMS. Database management systems are often classified according to the database model that they support; the most popular database systems since the 1980s have all supported the relational model as represented by the SQL language.[disputed – discuss] Sometimes a DBMS is loosely referred to as a 'database'.

qas: question: How is data accessed?
answers: text: by a "database management system" (DBMS)

question: A DBMS consists of what?
answers: text: an integrated set of computer software

question: How much data can a DBMS store?
answers: text: large quantities

question: What does a database refer to informally?

question: What requires a user to use more than one database?

question: What allows the entry, storage and retrieval of only small quantities of information?

question: How much data is typically lost by a DBMS?
context: Formally, a "database" refers to a set of related data and the way it is organized. Access to these data is usually provided by a "database management system" (DBMS) consisting of an integrated set of computer software that allows users to interact with one or more databases and provides access to all of the data contained in the database (although restrictions may exist that limit access to particular data). The DBMS provides various functions that allow entry, storage and retrieval of large quantities of information and provides ways to manage how that information is organized.

qas: question: What is used to recover data if disks suffer a failure?
answers: text: RAID

question: How can large quantities of data be accessed?
answers: text: Hardware database accelerators

question: What do most database applications contain?
answers: text: DBMSs

question: What is required for a modern DBMS to function?
answers: text: standard operating system

question: What is used to destroy data if disks suffer a failure?

question: How can no quantities of data be accessed?

question: What do most database applications not integrate?

question: What is required for a broken DBMS to function?

question: What are non-dedicated computers that hold databases called?
context: Physically, database servers are dedicated computers that hold the actual databases and run only the DBMS and related software. Database servers are usually multiprocessor computers, with generous memory and RAID disk arrays used for stable storage. RAID is used for recovery of data if any of the disks fail. Hardware database accelerators, connected to one or more servers via a high-speed channel, are also used in large volume transaction processing environments. DBMSs are found at the heart of most database applications. DBMSs may be built around a custom multitasking kernel with built-in networking support, but modern DBMSs typically rely on a standard operating system to provide these functions. from databases before the inception of Structured Query Language (SQL). The data recovered was disparate, redundant and disorderly, since there was no proper method to fetch it and arrange it in a concrete structure.[citation needed]

qas: question: How long can it take to create a DBMS?
answers: text: thousands of human years

question: Name three DBMSs that have been used since the 1970s.
answers: text: Adabas, Oracle and DB2

question: How is the cost to create a DBMS distributed?
answers: text: spread over a large number of users

question: Name an example of a general-purpose DBMS.
answers: text: an email system

question: How long can it take to search for a DBMS?

question: What are three DBMSs that have been used during the 1960s?

question: How is the cost to remove a DBMS distributed?

question: What is always the optimal solution to manage databases?
context: A DBMS has evolved into a complex software system and its development typically requires thousands of human years of development effort.[a] Some general-purpose DBMSs such as Adabas, Oracle and DB2 have been undergoing upgrades since the 1970s. General-purpose DBMSs aim to meet the needs of as many applications as possible, which adds to the complexity. However, the fact that their development cost can be spread over a large number of users means that they are often the most cost-effective approach. However, a general-purpose DBMS is not always the optimal solution: in some cases a general-purpose DBMS may introduce unnecessary overhead. Therefore, there are many examples of systems that use special-purpose databases. A common example is an email system that performs many of the functions of a general-purpose DBMS such as the insertion and deletion of messages composed of various items of data or associating messages with a particular email address; but these functions are limited to what is required to handle email and don't provide the user with all of the functionality that would be available using a general-purpose DBMS.

qas: question: How are many databases accessed?
answers: text: application software

question: How do administrators work with the DBMS?
answers: text: through dedicated interfaces

question: What is a way for programmers to use the DBMS?
answers: text: wire protocol

question: How are no databases accessed?

question: How do administrators no longer work with the DBMS?

question: What is a way for programmers to avoid DBMS?

question: Who is not typically allowed to interact with a DBMS?

question: Who needs less knowledge and understanding about how DBMSs operate?
context: Many other databases have application software that accesses the database on behalf of end-users, without exposing the DBMS interface directly. Application programmers may use a wire protocol directly, or more likely through an application programming interface. Database designers and database administrators interact with the DBMS through dedicated interfaces to build and maintain the applications' databases, and thus need some more knowledge and understanding about how DBMSs operate and the DBMSs' external interfaces and tuning parameters.

qas: question: Who created the relational model of DBMS?
answers: text: Edgar F. Codd

question: Instead of using links, how was information found in a relational model?
answers: text: by content

question: In what decade did computer hardware become able to handle a relational system?
answers: text: 1980s

question: What type of system in still prominent to this day?
answers: text: relational systems

question: What database language is the most prominent?
answers: text: SQL

question: Who was falsely misrepresented as having created the relational model of DBMS?

question: How was information lost in a relational model?

question: What decade did computer hardware lose the ability to handle a relational system?

question: What type of system in rarely seen to this day?

question: What database language is now outlawed?
context: The relational model, first proposed in 1970 by Edgar F. Codd, departed from this tradition by insisting that applications should search for data by content, rather than by following links. The relational model employs sets of ledger-style tables, each used for a different type of entity. Only in the mid-1980s did computing hardware become powerful enough to allow the wide deployment of relational systems (DBMSs plus applications). By the early 1990s, however, relational systems dominated in all large-scale data processing applications, and as of 2015[update] they remain dominant : IBM DB2, Oracle, MySQL and Microsoft SQL Server are the top DBMS. The dominant database language, standardised SQL for the relational model, has influenced database languages for other data models.[citation needed]

qas: question: When were DBMSs first used commercially?
answers: text: mid-1960s

question: What group discovered COBOL?
answers: text: Database Task Group

question: Why was COBOL created?
answers: text: Interest in a standard

question: What was the standard protocol called?
answers: text: CODASYL approach

question: When was the standard protocol completed?
answers: text: 1971

question: When were DBMSs last used commercially?

question: What group destroyed COBOL?

question: Why was COBOL removed?

question: When was the standard taken away?

question: What was the name of the incomplete standard?
context: As computers grew in speed and capability, a number of general-purpose database systems emerged; by the mid-1960s a number of such systems had come into commercial use. Interest in a standard began to grow, and Charles Bachman, author of one such product, the Integrated Data Store (IDS), founded the "Database Task Group" within CODASYL, the group responsible for the creation and standardization of COBOL. In 1971 the Database Task Group delivered their standard, which generally became known as the "CODASYL approach", and soon a number of commercial products based on this approach entered the market.

qas: question: What was the DBMS created by IBM called?
answers: text: Information Management System (IMS)

question: What was the purpose of the IBM DBMS?
answers: text: the Apollo program

question: What is the classification of IMS?
answers: text: hierarchical database

question: What was the name of Bachman's Turing Award presentation in 1973?
answers: text: The Programmer as Navigator

question: What was the DBMS designed for IBM by a third-party called?

question: What was irrelevant to the IBM DBMS?

question: What is the classification of IMS not considered?

question: What was the name of Bachman's Turing Award presentation in 1972?

question: When did IBM lose their own DBMS?
context: IBM also had their own DBMS in 1966, known as Information Management System (IMS). IMS was a development of software written for the Apollo program on the System/360. IMS was generally similar in concept to CODASYL, but used a strict hierarchy for its model of data navigation instead of CODASYL's network model. Both concepts later became known as navigational databases due to the way data was accessed, and Bachman's 1973 Turing Award presentation was The Programmer as Navigator. IMS is classified[by whom?] as a hierarchical database. IDMS and Cincom Systems' TOTAL database are classified as network databases. IMS remains in use as of 2014[update].

qas: question: Who proposed using a table to store data?
answers: text: Codd

question: How is data accessed in a table?
answers: text: A linked-list system

question: What model solved the problem of databases where information was missing?
answers: text: relational

question: What system assists a user in seeing a table?
answers: text: DBMS

question: Who proposed using a table to remove data?

question: How is data lost in a table?

question: What model couldn't solve the problem of databases where information was missing?

question: What system can't assist a user in seeing a table?
context: In this paper, he described a new system for storing and working with large databases. Instead of records being stored in some sort of linked list of free-form records as in CODASYL, Codd's idea was to use a "table" of fixed-length records, with each table used for a different type of entity. A linked-list system would be very inefficient when storing "sparse" databases where some of the data for any one record could be left empty. The relational model solved this by splitting the data into a series of normalized tables (or relations), with optional elements being moved out of the main table to where they would take up room only if needed. Data may be freely inserted, deleted and edited in these tables, with the DBMS doing whatever maintenance needed to present a table view to the application/user.

qas: question: How was the relational model able to improve over time?
answers: text: without constant rewriting of links and pointers

question: What is the relationship called in a hierarchical model?
answers: text: one-to-many

question: What is the relationship called in a navigational model?
answers: text: many-to-many

question: What is a third type of model that can be combined with heirarchical and navigation models?
answers: text: tabular

question: How was the relational model able to degrade over time?

question: What is the only kind of relationship called?

question: What is the relationship that is avoided in a navigational model?

question: What is a third type of model that can't be combined with hierarchical and navigation models?
context: The relational model also allowed the content of the database to evolve without constant rewriting of links and pointers. The relational part comes from entities referencing other entities in what is known as one-to-many relationship, like a traditional hierarchical model, and many-to-many relationship, like a navigational (network) model. Thus, a relational model can express both hierarchical and navigational models, as well as its native tabular model, allowing for pure or combined modeling in terms of these three models, as the application requires.

qas: question: How is a database system frequently used?
answers: text: to track information about users

question: How is information stored in a navigational system?
answers: text: in a single record

question: What happens to blank data fields in a navigational system?
answers: text: not be placed in the database

question: How is information stored in a relational system?
answers: text: normalized into a user table

question: How is a database system rarely used?

question: How is information discarded in a navigational system?

question: What happens to full data fields in a navigational system?

question: How is information lost in a relational system?
context: For instance, a common use of a database system is to track information about users, their name, login information, various addresses and phone numbers. In the navigational approach all of this data would be placed in a single record, and unused items would simply not be placed in the database. In the relational approach, the data would be normalized into a user table, an address table and a phone number table (for instance). Records would be created in these optional tables only if the address or phone numbers were actually provided.

qas: question: How is information accessed in a relational model?
answers: text: a "key"

question: What is a key used for?
answers: text: uniquely defining a particular record

question: What technique is used to collect into one place?
answers: text: re-linking

question: How is data in an optional table accessed?
answers: text: by searching for this key

question: How is information hidden in a relational model?

question: What is a key no longer used for?

question: What technique is used to collect into nowhere?

question: How is data in an optional table removed?
context: Linking the information back together is the key to this system. In the relational model, some bit of information was used as a "key", uniquely defining a particular record. When information was being collected about a user, information stored in the optional tables would be found by searching for this key. For instance, if the login name of a user is unique, addresses and phone numbers for that user would be recorded with the login name as its key. This simple "re-linking" of related data back into a single collection is something that traditional computer languages are not designed for.

qas: question: How does a program collect information using a navigational system?
answers: text: require programs to loop

question: What is used to solve the problem of looping?
answers: text: a set-oriented language

question: What computer language came about as a result of the looping problem?
answers: text: SQL

question: What type of math was used to create a system to find data sets?
answers: text: tuple calculus

question: Who used tuple calculus to show the functionality of databases?
answers: text: Codd

question: How does a program collect information using a normalized system?

question: What is used to create the problem of looping?

question: What computer language lost popularity as a result of the looping problem?

question: What type of physics was used to create a system to find data sets?

question: Who used tuple calculus to hide the functionality of databases?
context: Just as the navigational approach would require programs to loop in order to collect records, the relational approach would require loops to collect information about any one record. Codd's solution to the necessary looping was a set-oriented language, a suggestion that would later spawn the ubiquitous SQL. Using a branch of mathematics known as tuple calculus, he demonstrated that such a system could support all the operations of normal databases (inserting, updating etc.) as well as providing a simple system for finding and returning sets of data in a single operation.

qas: question: Who used Codd's paper at Berkeley to improve a geographical database?
answers: text: Eugene Wong and Michael Stonebraker

question: What was the name of the project to create a geographical database?
answers: text: INGRES

question: When was INGRES first tested?
answers: text: 1973

question: What computer language was used in INGRES to access data?
answers: text: QUEL

question: Is QUEL still used to access data in INGRES?
answers: text: INGRES moved to the emerging SQL standard

question: Who used Codd's paper at Yale to improve a geographical database?

question: What was the name of the project to steal a geographical database?

question: When was INGRES first avoided?

question: What computer language was used in INGRES to fabricate data?

question: What year did INGRES stop widespread use?
context: Codd's paper was picked up by two people at Berkeley, Eugene Wong and Michael Stonebraker. They started a project known as INGRES using funding that had already been allocated for a geographical database project and student programmers to produce code. Beginning in 1973, INGRES delivered its first test products which were generally ready for widespread use in 1979. INGRES was similar to System R in a number of ways, including the use of a "language" for data access, known as QUEL. Over time, INGRES moved to the emerging SQL standard.

qas: question: What is a CAFS accelerator?
answers: text: a hardware disk controller with programmable search capabilities

question: Did the CAFS accelerator work as planned?
answers: text: efforts were generally unsuccessful

question: How are today's database systems run?
answers: text: general-purpose hardware

question: Name a company that is still working on the CAFS accellerator?
answers: text: Netezza and Oracle (Exadata)

question: What is a CAFS decelerator?

question: What is no longer used in modern database systems?

question: What companies still work on the CAFS decelerator?

question: What are rarely seen nowadays?

question: What was a failed approach to hardware support for database management?
context: Another approach to hardware support for database management was ICL's CAFS accelerator, a hardware disk controller with programmable search capabilities. In the long term, these efforts were generally unsuccessful because specialized database machines could not keep pace with the rapid development and progress of general-purpose computers. Thus most database systems nowadays are software systems running on general-purpose hardware, using general-purpose computer data storage. However this idea is still pursued for certain applications by some companies like Netezza and Oracle (Exadata).

qas: question: What is the system IBM created using Codd's research?
answers: text: System R

question: When was IBM's system released?
answers: text: 1974/5

question: What did System R work on to change the way data was stored?
answers: text: multi-table systems

question: When customers first tested IBM's system, what computer language had been added? 
answers: text: SQL

question: What was the name of the database product created by IBM?
answers: text: SQL/DS, and, later, Database 2 (DB2)

question: What is the system IBM lost using Codd's research?

question: When was IBM's system stolen?

question: What did System R avoid to change the way data was stored?

question: When customers first tested IBM's system, what computer language had been removed?

question: What was the name of the database product created by IBN?
context: IBM started working on a prototype system loosely based on Codd's concepts as System R in the early 1970s. The first version was ready in 1974/5, and work then started on multi-table systems in which the data could be split so that all of the data for a record (some of which is optional) did not have to be stored in a single large "chunk". Subsequent multi-user versions were tested by customers in 1978 and 1979, by which time a standardized query language – SQL[citation needed] – had been added. Codd's ideas were establishing themselves as both workable and superior to CODASYL, pushing IBM to develop a true production version of System R, known as SQL/DS, and, later, Database 2 (DB2).

qas: question: Who created dBASE?
answers: text: C. Wayne Ratliff

question: Why was dBASE successful?
answers: text: lightweight and easy for any computer user to understand out of the box

question: Why was dBASE unique?
answers: text: data manipulation is done by dBASE

question: What is a benefit of using dBASE?
answers: text: managing space allocation

question: Who created BASE?

question: Why was dBASE unsuccessful?

question: Why was dBASE considered common?

question: What is the only benefit of using dBASE?

question: When was BASE the top selling software title?
context: The 1980s ushered in the age of desktop computing. The new computers empowered their users with spreadsheets like Lotus 1-2-3 and database software like dBASE. The dBASE product was lightweight and easy for any computer user to understand out of the box. C. Wayne Ratliff the creator of dBASE stated: "dBASE was different from programs like BASIC, C, FORTRAN, and COBOL in that a lot of the dirty work had already been done. The data manipulation is done by dBASE instead of by the user, so the user can concentrate on what he is doing, rather than having to mess with the dirty details of opening, reading, and closing files, and managing space allocation." dBASE was one of the top selling software titles in the 1980s and early 1990s.

qas: question: In the 1990s, what type of programming changed the handling of databases?
answers: text: object-oriented

question: What term is used for the difficulty in database table and programmed object translation?
answers: text: object-relational impedance mismatch

question: How is the problem of object-relational impedance mismatch corrected?
answers: text: object-oriented language

question: What is the library programmers use to solve object-relational impedance mismatch?
answers: text: object-relational mappings (ORMs)

question: What type of programming did not influence databases?

question: What term is no longer used for the difficulty in database table and programmed object translation?

question: How is the problem of object-relational impedance mismatch started?

question: What is the hardware programmers use to solve object-relational impedance mismatch?
context: The 1990s, along with a rise in object-oriented programming, saw a growth in how data in various databases were handled. Programmers and designers began to treat the data in their databases as objects. That is to say that if a person's data were in a database, that person's attributes, such as their address, phone number, and age, were now considered to belong to that person instead of being extraneous data. This allows for relations between data to be relations to objects and their attributes and not to individual fields. The term "object-relational impedance mismatch" described the inconvenience of translating between programmed objects and database tables. Object databases and object-relational databases attempt to solve this problem by providing an object-oriented language (sometimes as extensions to SQL) that programmers can use as alternative to purely relational SQL. On the programming side, libraries known as object-relational mappings (ORMs) attempt to solve the same problem.

qas: question: What kind of database is XML?
answers: text: structured document-oriented database

question: Where are XML databases frequently used?
answers: text: enterprise database management

question: How is XML used in enterprise database management?
answers: text: machine-to-machine data

question: What type of processing is used in enterprise database software?
answers: text: ACID-compliant transaction processing

question: What kind of database is ZML?

question: Where are XML databases never used?

question: How is XML bypassed in enterprise database management?

question: What type of processing is forbidden in enterprise database software?
context: 
XML databases are a type of structured document-oriented database that allows querying based on XML document attributes. XML databases are mostly used in enterprise database management, where XML is being used as the machine-to-machine data interoperability standard. XML database management systems include commercial software MarkLogic and Oracle Berkeley DB XML, and a free use software Clusterpoint Distributed XML/JSON Database. All are enterprise software database platforms and support industry standard ACID-compliant transaction processing with strong database consistency characteristics and high level of database security.

qas: question: What explains the difficulty in a system containing availability, consistency, and partition tolerance guarantees?
answers: text: the CAP theorem

question: How many guarantees will most databases tolerate?
answers: text: two

question: What is used to offer a balance in guarantees?
answers: text: eventual consistency

question: What can't explain the difficulty in a system containing availability, consistency, and partition tolerance guarantees?

question: How many guarantees will most databases destroy?

question: What can satisfy all guarantees at the same time?

question: What is used to discourage eventual consistency?

question: What has had low demand in recent years?
context: In recent years there was a high demand for massively distributed databases with high partition tolerance but according to the CAP theorem it is impossible for a distributed system to simultaneously provide consistency, availability and partition tolerance guarantees. A distributed system can satisfy any two of these guarantees at the same time, but not all three. For that reason many NoSQL databases are using what is called eventual consistency to provide both availability and partition tolerance guarantees with a reduced level of data consistency.

qas: question: What should a conceptual data model do?
answers: text: reflects the structure of the information to be held

question: What makes a successful data model?
answers: text: accurately reflect the possible state of the external world being modeled

question: What must one understand in order to create a successful data model?
answers: text: the application domain

question: Asking questions about an organization's needs will help to create what?
answers: text: definitions of the terminology used for entities

question: What does a conceptual data model never do?

question: What data model is no longer a popular approach?

question: What must one have no knowledge of in order to create a successful data model?

question: Who is not allowed to produce a conceptual data model?

question: What involves asking shallow questions to improve a data model?
context: The first task of a database designer is to produce a conceptual data model that reflects the structure of the information to be held in the database. A common approach to this is to develop an entity-relationship model, often with the aid of drawing tools. Another popular approach is the Unified Modeling Language. A successful data model will accurately reflect the possible state of the external world being modeled: for example, if people can have more than one phone number, it will allow this information to be captured. Designing a good conceptual data model requires a good understanding of the application domain; it typically involves asking deep questions about the things of interest to an organisation, like "can a customer also be a supplier?", or "if a product is sold with two different forms of packaging, are those the same product or different products?", or "if a plane flies from New York to Dubai via Frankfurt, is that one flight or two (or maybe even three)?". The answers to these questions establish definitions of the terminology used for entities (customers, products, flights, flight segments) and their relationships and attributes.

qas: question: In what form is the output of a logical database design?
answers: text: schema

question: Which data model is displayed as a specific model that uses DBMS?
answers: text: logical

question: A conceptual data model in separate from the choice of what?
answers: text: database technology

question: What form is the input of a logical database design?

question: Which data model is displayed as a nonspecific model that uses DBMS?

question: What is the conceptual data model dependent on?

question: What terms are no longer used interchangeably?
context: Having produced a conceptual data model that users are happy with, the next stage is to translate this into a schema that implements the relevant data structures within the database. This process is often called logical database design, and the output is a logical data model expressed in the form of a schema. Whereas the conceptual data model is (in theory at least) independent of the choice of database technology, the logical data model will be expressed in terms of a particular database model supported by the chosen DBMS. (The terms data model and database model are often used interchangeably, but in this article we use data model for the design of a specific database, and database model for the modelling notation used to express that design.)

qas: question: What decisions must be made in the last stage of database design?
answers: text: performance, scalability, recovery, security

question: What is an important goal in in this final stage?
answers: text: data independence

question: What factor is reflected in performance requirements?
answers: text: Physical design

question: What decisions are optional in the last stage of database design?

question: What is an irrelevant goal in the final stage?

question: What factor is not reflected in performance requirements?

question: What requires no knowledge of the expected workload?

question: What is no longer a key goal during the final stage?
context: The final stage of database design is to make the decisions that affect performance, scalability, recovery, security, and the like. This is often called physical database design. A key goal during this stage is data independence, meaning that the decisions made for performance optimization purposes should be invisible to end-users and applications. Physical design is driven mainly by performance requirements, and requires a good knowledge of the expected workload and access patterns, and a deep understanding of the features offered by the chosen DBMS.

qas: question: How many conceptual or physical views of data are there?
answers: text: one

question: How many different external views of data are there?
answers: text: any number

question: What is the benefit of external views of data?
answers: text: see database information in a more business-related way

question: How many conceptual or physical views of data do not exist?

question: How many duplicated external views of data are there?

question: What is the disadvantage of external views of data?

question: Who is not allowed to see database information?
context: While there is typically only one conceptual (or logical) and physical (or internal) view of the data, there can be any number of different external views. This allows users to see database information in a more business-related way rather than from a technical, processing viewpoint. For example, a financial department of a company needs the payment details of all employees as part of the company's expenses, but does not need details about employees that are the interest of the human resources department. Thus different departments need different views of the company's database.

qas: question: What does the conceptual view offer?
answers: text: a level of indirection between internal and external

question: How does the conceptual view handle how data is managed?
answers: text: abstracts away details

question: What type of view does the conceptual view offer?
answers: text: common

question: What does the conceptual view ignore?

question: How does the conceptual view handle how data is erased?

question: What type of view does the conceptual view degrade?

question: What view can't be presented by a different data model?
context: The conceptual view provides a level of indirection between internal and external. On one hand it provides a common view of the database, independent of different external view structures, and on the other hand it abstracts away details of how the data are stored or managed (internal level). In principle every level, and even every external view, can be presented by a different data model. In practice usually a given DBMS uses the same data model for both the external and the conceptual levels (e.g., relational model). The internal level, which is hidden inside the DBMS and depends on its implementation, requires a different level of detail and uses its own types of data structure types.

qas: question: What is responsible for putting information into permanent storage?
answers: text: database engine

question: What is database storage?
answers: text: physical materialization of a database

question: What do database administrators closely monitor?
answers: text: storage properties and configuration setting

question: While working, does DBMS store information in one place?
answers: text: several types of storage

question: What are huge quantities of information stored as?
answers: text: bits

question: What is responsible for losing information in permanent storage?

question: What is no longer considered database storage?

question: What do database administrators loosely monitor?

question: How many types of storage are not utilized for DBMS?

question: What are no quantities of information stored as?
context: Database storage is the container of the physical materialization of a database. It comprises the internal (physical) level in the database architecture. It also contains all the information needed (e.g., metadata, "data about the data", and internal data structures) to reconstruct the conceptual level and external level from the internal level when needed. Putting data into permanent storage is generally the responsibility of the database engine a.k.a. "storage engine". Though typically accessed by a DBMS through the underlying operating system (and often utilizing the operating systems' file systems as intermediates for storage layout), storage properties and configuration setting are extremely important for the efficient operation of the DBMS, and thus are closely maintained by database administrators. A DBMS, while in operation, always has its database residing in several types of storage (e.g., memory and external storage). The database data and the additional needed information, possibly in very large amounts, are coded into bits. Data typically reside in the storage in structures that look completely different from the way the data look in the conceptual and external levels, but in ways that attempt to optimize (the best possible) these levels' reconstruction when needed by users and programs, as well as for computing additional types of needed information from the data (e.g., when querying the database).

qas: question: What does database access limit?
answers: text: who (a person or a certain computer program) is allowed to access what information

question: What are examples of database objects?
answers: text: record types, specific records, data structures

question: Who sets database access?
answers: text: special authorized (by the database owner) personnel

question: What does database access have no influence on?

question: What are examples of the only kind of database errors?

question: Who has no database access?

question: Who uses dedicated unprotected security DBMS interfaces?
context: Database access control deals with controlling who (a person or a certain computer program) is allowed to access what information in the database. The information may comprise specific database objects (e.g., record types, specific records, data structures), certain computations over certain objects (e.g., query types, or specific queries), or utilizing specific access paths to the former (e.g., using specific indexes or other data structures to access information). Database access controls are set by special authorized (by the database owner) personnel that uses dedicated protected security DBMS interfaces.

qas: question: What does data security avoid?
answers: text: unauthorized users from viewing or updating the database

question: What is a subset of a database called that can be accessed by using a password?
answers: text: subschemas

question: What is possible when a DBMS interrogate and update a database?
answers: text: managing personal databases

question: What does data security support?

question: What is a subset of a database called that can be accessed by using a spell?

question: What is possible when a DBMS corrupts a database?

question: Who can view the entire contents of an employee database?
context: This may be managed directly on an individual basis, or by the assignment of individuals and privileges to groups, or (in the most elaborate models) through the assignment of individuals and groups to roles which are then granted entitlements. Data security prevents unauthorized users from viewing or updating the database. Using passwords, users are allowed access to the entire database or subsets of it called "subschemas". For example, an employee database can contain all the data about an individual employee, but one group of users may be authorized to view only payroll data, while others are allowed access to only work history and medical data. If the DBMS provides a way to interactively enter and update the database, as well as interrogate it, this capability allows for managing personal databases.

qas: question: What is a unit of work called in a database?
answers: text: transaction

question: How can database transactions ensure accuracy after a crash?
answers: text: fault tolerance

question: Are transactions limited?
answers: text: Each transaction has well defined boundaries

question: What is a unit of play called in a database?

question: How can database transactions lower accuracy after a crash?

question: What has poorly defined boundaries in a database?

question: What has no ability to recover from a crash?

question: What always encapsulates only one transaction?
context: Database transactions can be used to introduce some level of fault tolerance and data integrity after recovery from a crash. A database transaction is a unit of work, typically encapsulating a number of operations over a database (e.g., reading a database object, writing, acquiring lock, etc.), an abstraction supported in database and also other systems. Each transaction has well defined boundaries in terms of which program/code executions are included in that transaction (determined by the transaction's programmer via special transaction commands).

qas: question: Can a DBMS be transfered to a different DBMS?
answers: text: ano

question: Why would someone attempt to unite two different databases?
answers: text: primarily economical

question: In order to merge, what must the database maintain?
answers: text: database related application

question: What are the important parts of the database related application that should be moved?
answers: text: conceptual and external architectural levels

question: How can a DBMS database migration be made easier?
answers: text: vendor provides tools

question: What is portable from one DBMS to another?

question: What kind of database is migration impossible from?

question: What is always an easy and cheap project for an individual?

question: What no longer exist to help migration between specific DBMSs?

question: What is not typically provided by a DBMS vendor?
context: A database built with one DBMS is not portable to another DBMS (i.e., the other DBMS cannot run it). However, in some situations it is desirable to move, migrate a database from one DBMS to another. The reasons are primarily economical (different DBMSs may have different total costs of ownership or TCOs), functional, and operational (different DBMSs may have different capabilities). The migration involves the database's transformation from one DBMS type to another. The transformation should maintain (if possible) the database related application (i.e., all related application programs) intact. Thus, the database's conceptual and external architectural levels should be maintained in the transformation. It may be desired that also some aspects of the architecture internal level are maintained. A complex or large database migration may be a complicated and costly (one-time) project by itself, which should be factored into the decision to migrate. This in spite of the fact that tools may exist to help migration between specific DBMSs. Typically a DBMS vendor provides tools to help importing databases from other popular DBMSs.

qas: question: Name a reason to take a database backward in time?
answers: text: database is found corrupted

question: Is each database backup kept in the same file?
answers: text: dedicated backup files

question: Who can restore a database that has been corrupted?
answers: text: database administrator

question: What parameter is requiret to restore a database?
answers: text: desired point in time

question: What is not a reason to take a database backward in time?

question: What type of file has no dedicated ones involved?

question: Who can restore a database that has been deleted?

question: What can't be restored to a previous date?

question: What operation can be done only once per year?
context: Sometimes it is desired to bring a database back to a previous state (for many reasons, e.g., cases when the database is found corrupted due to a software error, or if it has been updated with erroneous data). To achieve this a backup operation is done occasionally or continuously, where each desired database state (i.e., the values of its data and their embedding in database's data structures) is kept within dedicated backup files (many techniques exist to do this effectively). When this state is needed, i.e., when it is decided by a database administrator to bring the database back to this state (e.g., by specifying this state by a desired point in time when the database was in this state), these files are utilized to restore that state.

qas: question: How can static analysis be useful with query languages?
answers: text: software verification

question: What do query languages support in abstract interpretation frameworks?
answers: text: sound approximation techniques

question: What is a security measure that uses a relational database system?
answers: text: watermarking

question: Can query languages be adjusted?
answers: text: according to suitable abstractions of the concrete domain of data

question: Why is static analysis impossible with query languages?

question: What do query languages oppose in abstract interpretation frameworks?

question: What is a security measure that no longer uses a relational database system?

question: What has very few interesting applications?

question: What techniques are now forbidden for software verification?
context: Static analysis techniques for software verification can be applied also in the scenario of query languages. In particular, the *Abstract interpretation framework has been extended to the field of query languages for relational databases as a way to support sound approximation techniques. The semantics of query languages can be tuned according to suitable abstractions of the concrete domain of data. The abstraction of relational database system has many interesting applications, in particular, for security purposes, such as fine grained access control, watermarking, etc.