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  2. Partition (database) - Wikipedia

    en.wikipedia.org/wiki/Partition_(database)

    They take a partitioning key and assign a partition based on certain criteria. Some common criteria include: Range partitioning: selects a partition by determining if the partitioning key is within a certain range. An example could be a partition for all rows where the "zipcode" column has a value between 70000 and 79999. It distributes tuples ...

  3. Shard (database architecture) - Wikipedia

    en.wikipedia.org/wiki/Shard_(database_architecture)

    Horizontal partitioning splits one or more tables by row, usually within a single instance of a schema and a database server. It may offer an advantage by reducing index size (and thus search effort) provided that there is some obvious, robust, implicit way to identify in which partition a particular row will be found, without first needing to search the index, e.g., the classic example of the ...

  4. CAP theorem - Wikipedia

    en.wikipedia.org/wiki/CAP_theorem

    The PACELC theorem, introduced in 2010, [8] builds on CAP by stating that even in the absence of partitioning, there is another trade-off between latency and consistency. PACELC means, if partition (P) happens, the trade-off is between availability (A) and consistency (C); Else (E), the trade-off is between latency (L) and consistency (C).

  5. PACELC theorem - Wikipedia

    en.wikipedia.org/wiki/PACELC_theorem

    The tradeoff between availability, consistency and latency, as described by the PACELC theorem. In database theory, the PACELC theorem is an extension to the CAP theorem.It states that in case of network partitioning (P) in a distributed computer system, one has to choose between availability (A) and consistency (C) (as per the CAP theorem), but else (E), even when the system is running ...

  6. List of archive formats - Wikipedia

    en.wikipedia.org/wiki/List_of_archive_formats

    The replacement for the .sit format that supports more compression methods, UNIX file permissions, long file names, very large files, more encryption options, data specific compressors (JPEG, Zip, PDF, 24-bit image, MP3). The free StuffIt Expander is available for Windows and OS X. .sqx SQX: Windows: Windows: Yes A royalty-free compressing format

  7. Hierarchical and recursive queries in SQL - Wikipedia

    en.wikipedia.org/wiki/Hierarchical_and_recursive...

    In SQL:1999 a recursive (CTE) query may appear anywhere a query is allowed. It's possible, for example, to name the result using CREATE [ RECURSIVE ] VIEW . [ 15 ] Using a CTE inside an INSERT INTO , one can populate a table with data generated from a recursive query; random data generation is possible using this technique without using any ...

  8. SQL syntax - Wikipedia

    en.wikipedia.org/wiki/SQL_syntax

    SQL includes operators and functions for calculating values on stored values. SQL allows the use of expressions in the select list to project data, as in the following example, which returns a list of books that cost more than 100.00 with an additional sales_tax column containing a sales tax figure calculated at 6% of the price.

  9. Comparison of relational database management systems - Wikipedia

    en.wikipedia.org/wiki/Comparison_of_relational...

    The SQL specification defines what an "SQL schema" is; however, databases implement it differently. To compound this confusion the functionality can overlap with that of a parent database. An SQL schema is simply a namespace within a database; things within this namespace are addressed using the member operator dot ".". This seems to be a ...