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  2. Database index - Wikipedia

    en.wikipedia.org/wiki/Database_index

    The non-clustered index tree contains the index keys in sorted order, with the leaf level of the index containing the pointer to the record (page and the row number in the data page in page-organized engines; row offset in file-organized engines). In a non-clustered index, The physical order of the rows is not the same as the index order.

  3. Unique key - Wikipedia

    en.wikipedia.org/wiki/Unique_key

    In SQL, the unique keys have a UNIQUE constraint assigned to them in order to prevent duplicates (a duplicate entry is not valid in a unique column). Alternate keys may be used like the primary key when doing a single-table select or when filtering in a where clause, but are not typically used to join multiple tables.

  4. Materialized view - Wikipedia

    en.wikipedia.org/wiki/Materialized_view

    In computing, a materialized view is a database object that contains the results of a query.For example, it may be a local copy of data located remotely, or may be a subset of the rows and/or columns of a table or join result, or may be a summary using an aggregate function.

  5. Data control language - Wikipedia

    en.wikipedia.org/wiki/Data_Control_Language

    Create, alter, and drop schema objects; Grant and revoke privileges and roles; Analyze information on a table, index, or cluster; Establish auditing options; Add comments to the data dictionary; So Oracle Database DDL commands include the Grant and revoke privileges which is actually part of Data control Language in Microsoft SQL server.

  6. Extensible Storage Engine - Wikipedia

    en.wikipedia.org/wiki/Extensible_Storage_Engine

    Tables grow automatically in response to data creation. Tables have one or more indexes. There must be at least one clustered index for record data. When no clustered index is defined by the application, an artificial index is used which orders and clusters records by the chronological order of record insertion.

  7. 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 ...

  8. Adaptive Server Enterprise - Wikipedia

    en.wikipedia.org/wiki/Adaptive_Server_Enterprise

    The key feature that made SQL Server attractive from the start was its high performance due to shared log writes, clustered indexes and a small memory footprint per user. As a result of these and other design features it performed well "out of the box". Sybase released SQL Server 4.2 in 1992.

  9. Block Range Index - Wikipedia

    en.wikipedia.org/wiki/Block_Range_Index

    A large database index would typically use B-tree algorithms. BRIN is not always a substitute for B-tree, it is an improvement on sequential scanning of an index, with particular (and potentially large) advantages when the index meets particular conditions for being ordered and for the search target to be a narrow set of these values.