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The computer UNIVAC 1 was created
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The UNIVAC was followed by IBM’s 701 in 1953 and 650 in 1954. Data could now be processed much faster and with fewer errors compared with manual systems.
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Are individual files were composed of records organised in some predetermined order. Although not a database because there was no one integrated data source
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IBM introduced hard disk drives which allowed direct access to data, these were relatively low capacity and expensive compared to tape system.
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COBOL and CODASYL languages were developed
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Hierarchical databases are no longer common, the structure of a hierarchical database relies on pointers.
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IBM created PL/1 programming language and a database know as IMS for the IBM´s series 360
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ACID (Atomicity, Consistency, Isolation, Durability) is a set of properties of database transactions intended to guarantee validity even in the event of errors, power failures, etc. In the context of databases, a sequence of database operations that satisfies the ACID properties is called a transaction.
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- The request phase a coordinating process sends a query to commit message to all other processes.
- In the commit phase the coordinator sends a message to the other processes which attempt to complete the commit. If any one process fails, all processes will execute a rollback
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The basis of a relational system is a series of tables of records each with specific attributes linked by a series of joins. These joins are created using foreign keys which are attribute(s) containing the same data as another tables primary key. A primary key is a unique identifier of a record in a table.
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It´s a type of database model where multiple member records or files can be linked to multiple owner files and vice versa.
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The data/information is represented in the form of objects. Object oriented structures such as hierarchies, aggregation and pointers are being introduced.
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SQL is a language used in programming and designed for managing data . Was the first commercial language for relational model.
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The concept behind a data warehouse is that it can store data generated by different systems in the organisation, not just transactions form the database. It´s a central repository of data in an organisation storing historical data and being constantly added to by current transactions