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  2. Database normalization - Wikipedia

    en.wikipedia.org/wiki/Database_normalization

    For this example it is assumed that each book has only one author. A table that conforms to the relational model has a primary key which uniquely identifies a row. In our example, the primary key is a composite key of {Title, Format} (indicated by the underlining):

  3. Block (data storage) - Wikipedia

    en.wikipedia.org/wiki/Block_(data_storage)

    Block storage is normally abstracted by a file system or database management system (DBMS) for use by applications and end users. The physical or logical volumes accessed via block I/O may be devices internal to a server, directly attached via SCSI or Fibre Channel , or distant devices accessed via a storage area network (SAN) using a protocol ...

  4. Block contention - Wikipedia

    en.wikipedia.org/wiki/Block_contention

    In database management systems, block contention (or data contention) refers to multiple processes or instances competing for access to the same index or data block at the same time. In general this can be caused by very frequent index or table scans, or frequent updates.

  5. First normal form - Wikipedia

    en.wikipedia.org/wiki/First_normal_form

    In a hierarchical database, a record can contain sets of child records ― known as repeating groups or table-valued attributes.If such a data model is represented as relations, a repeating group would be an attribute where the value is itself a relation.

  6. Database transaction schedule - Wikipedia

    en.wikipedia.org/wiki/Database_transaction_schedule

    In this example, the columns represent the different transactions in the schedule D. Schedule D consists of three transactions T1, T2, T3. First T1 Reads and Writes to object X, and then Commits. Then T2 Reads and Writes to object Y and Commits, and finally, T3 Reads and Writes to object Z and Commits.

  7. Category:Database management systems - Wikipedia

    en.wikipedia.org/wiki/Category:Database...

    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.

  8. Record locking - Wikipedia

    en.wikipedia.org/wiki/Record_locking

    Record locking is the technique of preventing simultaneous access to data in a database, to prevent inconsistent results.. The classic example is demonstrated by two bank clerks attempting to update the same bank account for two different transactions.

  9. Relational model - Wikipedia

    en.wikipedia.org/wiki/Relational_model

    The purpose of the relational model is to provide a declarative method for specifying data and queries: users directly state what information the database contains and what information they want from it, and let the database management system software take care of describing data structures for storing the data and retrieval procedures for ...