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To process this statement without an index the database software must look at the last_name column on every row in the table (this is known as a full table scan). With an index the database simply follows the index data structure (typically a B-tree ) until the Smith entry has been found; this is much less computationally expensive than a full ...
Microsoft Access versions from Access 2000 to Access 2010 included an "Upsizing Wizard" which could "upsize" (upgrade) a Jet database to "an equivalent database on SQL Server with the same table structure, data, and many other attributes of the original database". Reports, queries, macros and security were not handled by this tool, meaning that ...
Tables normally include a hidden rowid index column, which provides faster access. [29] If a table includes an INTEGER PRIMARY KEY column, SQLite will typically optimize it by treating it as an alias for the rowid, causing the contents to be stored as a strictly typed 64-bit signed integer and changing its behavior to be somewhat like an auto ...
The column set of the base table is the union of the column sets of these logical tables. Tagged columns make this possible because of their good handling of both multi-valued and sparse valued data. Since related data is stored together in the same record, it is accessed together thereby minimizing the number of disk accesses to perform the join.
In relational databases a virtual column is a table column whose value(s) is automatically computed using other columns values, or another deterministic expression. Virtual columns are defined of SQL:2003 as Generated Column, [1] and are only implemented by some DBMSs, like MariaDB, SQL Server, Oracle, PostgreSQL, SQLite and Firebird (database server) (COMPUTED BY syntax).
SpatiaLite is a spatial extension to SQLite, providing vector geodatabase functionality. It is similar to PostGIS, Oracle Spatial, and SQL Server with spatial extensions, although SQLite/SpatiaLite aren't based on client-server architecture: they adopt a simpler personal architecture. i.e. the whole SQL engine is directly embedded within the application itself: a complete database simply is an ...
The "help" index of commands in VFP 9 has several hundred commands and functions described. The examples below show how to code the creation and indexing of tables, however VFP has table and database builder screens which create the tables and indexes without making you write code. Output of the Data handling program.
LevelDB outperforms both SQLite and Kyoto Cabinet in write operations and sequential-order read operations. LevelDB also excels at batch writes, but is slower than SQLite when dealing with large values. The currently published benchmarks were updated after SQLite configuration mistakes were noted in an earlier version of the results. [12]