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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.
The files have names that begin with the table name and have an extension to indicate the file type. MySQL uses a .frm file to store the definition of the table, but this file is not a part of the MyISAM engine; instead it is a part of the server. The data file has a .MYD (MYData) extension. The index file has a .MYI (MYIndex) extension.
To find the Name for ID 13, an index on (ID) is useful, but the record must still be read to get the Name. However, an index on (ID, Name) contains the required data field and eliminates the need to look up the record. Covering indexes are each for a specific table.
Views can make it easier to create lossless join decomposition. Just as rows in a base table lack any defined ordering, rows available through a view do not appear with any default sorting. A view is a relational table, and the relational model defines a table as a set of rows.
MySQL (/ ˌ m aɪ ˌ ɛ s ˌ k juː ˈ ɛ l /) [6] is an open-source relational database management system (RDBMS). [6] [7] Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, [1] and "SQL", the acronym for Structured Query Language.
(A database segment is a database object which occupies physical space such as table data and indexes.) Once created, a tablespace can be referred to by name when creating database segments. Once created, a tablespace can be referred to by name when creating database segments.
Indexes, a data structure providing faster queries (at the expense of slower writing and storage to maintain the index structure) Views, a virtual table that is made as it is queried; Synonyms, alternate names for a table, view, sequence or other object in a database; Stored procedures and user-defined functions
In databases, a partial index, also known as filtered index is an index which has some condition applied to it so that it includes a subset of rows in the table.. This allows the index to remain small, even though the table may be rather large, and have extreme selectivity.