The History of The History of DatabasesDatabases

•By Patrick Rogers-Ostema

What is a Database?What is a Database?

Webster.com: A usually large Webster.com: A usually large collection of data organized collection of data organized especially for rapid search and especially for rapid search and retrieval.retrieval.

Why are we here?Why are we here?Information Storage has been a challenge throughout human Information Storage has been a challenge throughout human

history and existed long before modern computer systems :history and existed long before modern computer systems :

• Government RecordsGovernment Records

• Dewey Decimal System(1870)Dewey Decimal System(1870)

While examples such as the Dewey Decimal System made While examples such as the Dewey Decimal System made information retrieval and indexing more efficient, it still information retrieval and indexing more efficient, it still required vast amounts of physical volume to store data and required vast amounts of physical volume to store data and relied on the human intellect to process trivial relations in relied on the human intellect to process trivial relations in that data.that data.

And along came the And along came the computer...computer...

Databases are Flower Databases are Flower Children of the 60’sChildren of the 60’s

• Charles Bachmann developed the first DBMS called Charles Bachmann developed the first DBMS called IDS while working at HoneywellIDS while working at Honeywell

– Network model where data relationships are represented Network model where data relationships are represented as a graphas a graph

• First commercially successful DBMS developed at IBM First commercially successful DBMS developed at IBM called IMScalled IMS

– Hierarchical model where data relationships are Hierarchical model where data relationships are represented as a treerepresented as a tree

– still in use today in IBM’s and American Airline’s SABRE still in use today in IBM’s and American Airline’s SABRE reservation systemreservation system

• Conference On DAta SYstems Languages(CODASYL) Conference On DAta SYstems Languages(CODASYL) model definedmodel defined

– network model but more standardizednetwork model but more standardized

Problems with first DBMS’Problems with first DBMS’

• Access to database was through low level pointer Access to database was through low level pointer operationsoperations

• Storage details depended on the type of data to be storedStorage details depended on the type of data to be stored

• Adding a field to the DB required rewriting the underlying Adding a field to the DB required rewriting the underlying access/modification schemeaccess/modification scheme

• Emphasis on records to be processed, not overall structureEmphasis on records to be processed, not overall structure

• User had to know physical structure of the DB in order to User had to know physical structure of the DB in order to query for informationquery for information

Overall first DBMS’ were very complex and inflexible Overall first DBMS’ were very complex and inflexible which made life difficult when it came to adding which made life difficult when it came to adding new applications or reorganizing the datanew applications or reorganizing the data

Relational DB’s to the rescue...

Edgar (Ted) CoddEdgar (Ted) Codd• Father of The Relational ModelFather of The Relational Model

• Oxford-trained mathematician working for IBM @ San Jose Oxford-trained mathematician working for IBM @ San Jose LaboratoryLaboratory

• In 1970, Codd released “A Relational Model of Data for In 1970, Codd released “A Relational Model of Data for Large Shared Data Banks.” This text first defined the Large Shared Data Banks.” This text first defined the Relational Model.Relational Model.– ““It provides a means of describing data with its natural It provides a means of describing data with its natural

structure only--that is, without superimposing any additional structure only--that is, without superimposing any additional structure for machine representation purposes. Accordingly, structure for machine representation purposes. Accordingly, it provides a basis for a high level data language which will it provides a basis for a high level data language which will yield maximal independence between programs on the one yield maximal independence between programs on the one hand and machine representation on the other.”(Codd 1970)hand and machine representation on the other.”(Codd 1970)

• In other words the Relational Model consisted of:In other words the Relational Model consisted of:– Data independence from hardware and storage Data independence from hardware and storage

implementation implementation

– Automatic navigation, or a high level, nonprocedural Automatic navigation, or a high level, nonprocedural language for accessing data. Instead of processing one language for accessing data. Instead of processing one record at a time, a programmer could use the language to record at a time, a programmer could use the language to specify single operations that would be performed across the specify single operations that would be performed across the entire data set.entire data set.

Codd’s 12(13) RulesCodd’s 12(13) Rules• 0. A relational DBMS must be able to manage databases entirely

through its relational capabilities.1. Information rule-- All information in a relational database (including table and column names) is represented explicitly as values in tables.2. Guaranteed access--Every value in a relational database is guaranteed to be accessible by using a combination of the table name, primary key value, and column name.3. Systematic null value support--The DBMS provides systematic support for the treatment of null values (unknown or inapplicable data), distinct from default values, and independent of any domain.4. Active, online relational catalog--The description of the database and its contents is represented at the logical level as tables and can therefore be queried using the database language.5. Comprehensive data sublanguage--At least one supported language must have a well-defined syntax and be comprehensive. It must support data definition, manipulation, integrity rules, authorization, and transactions.6. View updating rule--All views that are theoretically updatable can be updated through the system.

Codd’s 12(13) RulesCodd’s 12(13) Rules• 7. Set-level insertion, update, and deletion--The DBMS

supports not only set-level retrievals but also set-level inserts, updates, and deletes.8. Physical data independence--Application programs and ad hoc programs are logically unaffected when physical access methods or storage structures are altered.9. Logical data independence--Application programs and ad hoc programs are logically unaffected, to the extent possible, when changes are made to the table structures.10. Integrity independence--The database language must be capable of defining integrity rules. They must be stored in the online catalog, and they cannot be bypassed.11. Distribution independence--Application programs and ad hoc requests are logically unaffected when data is first distributed or when it is redistributed.12. Nonsubversion rule--It must not be possible to bypass the integrity rules defined through the database language by

using lower-level languages.

Codd vs. IBMCodd vs. IBM• Codd’s model had an immediate impact on research, Codd’s model had an immediate impact on research,

however, to become a legitimacy within the field, it had however, to become a legitimacy within the field, it had to survive at least two battles:to survive at least two battles:

– One in the technical community at largeOne in the technical community at large

– One within IBMOne within IBM

• Within IBMWithin IBM

– Conflict with existing product IMS which had been heavily Conflict with existing product IMS which had been heavily invested intoinvested into

– New technology had to prove itself before replacing New technology had to prove itself before replacing existing revenue producing productexisting revenue producing product

– Codd published his paper in open literature because no Codd published his paper in open literature because no one at IBM (himself included) recognized its eventual one at IBM (himself included) recognized its eventual impactimpact

– Outside technical community showed that the idea had Outside technical community showed that the idea had great potentialgreat potential

Codd vs. IBM (Continued)Codd vs. IBM (Continued)• Within IBMWithin IBM

– IBM declared IMS its sole strategic product, setting up Codd IBM declared IMS its sole strategic product, setting up Codd and his ideas as counter to company goalsand his ideas as counter to company goals

– Codd speaks out in spite of IBM’s dissatisfaction and Codd speaks out in spite of IBM’s dissatisfaction and promotes relational model to computer scientists. He promotes relational model to computer scientists. He arranges a public debate between himself and Charles arranges a public debate between himself and Charles Bachmann, who at the time was a key proponent of the Bachmann, who at the time was a key proponent of the CODASYL standard.CODASYL standard.

– Debate produced further criticism from IBM for undermining Debate produced further criticism from IBM for undermining its goals, but also proved his relational model as a its goals, but also proved his relational model as a cornerstone to the technical community.cornerstone to the technical community.

• Finally, Two main relational prototypes emerge in the Finally, Two main relational prototypes emerge in the 70’s70’s

– System R from IBMSystem R from IBM

– Ingres from UC-Berkeley Ingres from UC-Berkeley

System RSystem R• Prototype intended to provide a high-level, Prototype intended to provide a high-level,

nonnavigational, data-independent interface to many nonnavigational, data-independent interface to many users simultaneously, with high integrity and users simultaneously, with high integrity and robustness.robustness.

• Led to a query language called SEQUEL(Structured Led to a query language called SEQUEL(Structured English Query Language) later renamed to Structured English Query Language) later renamed to Structured Query Language(SQL) for legal reasons. Now a Query Language(SQL) for legal reasons. Now a standard for database access.standard for database access.

• Project finished with the conclusion that relational Project finished with the conclusion that relational databases were a feasible commercial productdatabases were a feasible commercial product

• Eventually evolved into SQL/DS which later became Eventually evolved into SQL/DS which later became DB2DB2

IngresIngres• Two scientists, Michael Stonebraker and Eugene Wong at Two scientists, Michael Stonebraker and Eugene Wong at

UC-Berkeley) became interested in relational databasesUC-Berkeley) became interested in relational databases

• Used QUEL as its query languageUsed QUEL as its query language

• Similar to System R, but based on different hardware and Similar to System R, but based on different hardware and operating systemoperating system

• Developers eventually branched off to form Ingres Corp, Developers eventually branched off to form Ingres Corp, Sybase, MS SQL Server, Britton-Lee.Sybase, MS SQL Server, Britton-Lee.

System R and Ingres inspire the development of System R and Ingres inspire the development of virtually all commercial relational databases, virtually all commercial relational databases, including those from Sybase, Informix, including those from Sybase, Informix, Tandem, and even Microsoft’s SQL ServerTandem, and even Microsoft’s SQL Server

Where’s Oracle!?Where’s Oracle!?• Larry Ellison learned of IBM’s work and founded Larry Ellison learned of IBM’s work and founded

Relational Software Inc. in 1977 in CaliforniaRelational Software Inc. in 1977 in California

• Their first product was a relational database based off Their first product was a relational database based off of IBM’s System R model and SQL technologyof IBM’s System R model and SQL technology

• Released in 1979, it was the first commercial RDBMS, Released in 1979, it was the first commercial RDBMS, beating IBM to the market by 2 years.beating IBM to the market by 2 years.

• In the 1980’s the company was renamed to Oracle In the 1980’s the company was renamed to Oracle Corporation and throughout the 80’s new features were Corporation and throughout the 80’s new features were added and performance improved as the price of added and performance improved as the price of hardware came down and Oracle became the largest hardware came down and Oracle became the largest independent RDBMS vendor.independent RDBMS vendor.

Entity-Relationship(ER) Entity-Relationship(ER) ModelsModels• Proposed by Peter Chen in 1976 for database design Proposed by Peter Chen in 1976 for database design

giving an important insight into conceptual data modelsgiving an important insight into conceptual data models

• Allows the designer to concentrate on the use of data Allows the designer to concentrate on the use of data instead of the logical table structureinstead of the logical table structure

1980’s1980’s• Birth of IBM PC. RDBMS market begins to boom.Birth of IBM PC. RDBMS market begins to boom.

• SQL becomes standardized through ANSI (American SQL becomes standardized through ANSI (American National Standards Institute) and ISO (International National Standards Institute) and ISO (International Organization for Standardization) Organization for Standardization)

• By Mid 80’s it had become apparent that there were some By Mid 80’s it had become apparent that there were some fields(medicine, multimedia, physics) where relational fields(medicine, multimedia, physics) where relational databases were not practical, due to the types of data databases were not practical, due to the types of data involved. involved.

– More flexibility was needed in how their data was represented More flexibility was needed in how their data was represented and accessed.and accessed.

• This led to research in Object Oriented Databases in which This led to research in Object Oriented Databases in which users could define their own methods of access to data users could define their own methods of access to data and how to represent and manipulate it. This coincided and how to represent and manipulate it. This coincided with the introduction of Object Oriented Programming with the introduction of Object Oriented Programming languages such as C++ which started to appearlanguages such as C++ which started to appear

1990’s1990’s• First OODBMS’ start to appear from companies like First OODBMS’ start to appear from companies like

Objectivity. Object Relational DBMS’ hybrids also begin Objectivity. Object Relational DBMS’ hybrids also begin to appear. to appear.

• Industry shakeout begins with fewer surviving companies Industry shakeout begins with fewer surviving companies offering increasingly complex products at higher prices. offering increasingly complex products at higher prices. Much of the development centers on client tools for Much of the development centers on client tools for application development such as: PowerBuilder(Sybase), application development such as: PowerBuilder(Sybase), Oracle Developer, Visual Basic, etcOracle Developer, Visual Basic, etc

• Development of personal/small business productivity Development of personal/small business productivity tools such as Excel and Access from Microsoft.tools such as Excel and Access from Microsoft.

• New application areas: Data warehousing and New application areas: Data warehousing and OLAP(Online Analytical Processing, a category of OLAP(Online Analytical Processing, a category of software tools that provides analysis of data stored in a software tools that provides analysis of data stored in a database), internet, multimedia, etc database), internet, multimedia, etc

Late 90’s-2000’sLate 90’s-2000’s• Large investment in internet companies fuels tools-Large investment in internet companies fuels tools-

market boom for Web/Internet/DB connectors:market boom for Web/Internet/DB connectors:

– Active Server Pages, Front page, Java Servlets, JDBC, Java Active Server Pages, Front page, Java Servlets, JDBC, Java Beans, ColdFusion, Dream Weaver, Oracle Developer Beans, ColdFusion, Dream Weaver, Oracle Developer 2000, etc2000, etc

• Open source projects come online with widespread use Open source projects come online with widespread use of gcc,cgi, Apache, MySQLof gcc,cgi, Apache, MySQL

• Three main companies dominate in the large DB Three main companies dominate in the large DB market: IBM, Microsoft, and Oraclemarket: IBM, Microsoft, and Oracle

OverviewOverview

The EndThe End

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