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Overview |
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Overview |
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Virtual Data Access Components (VirtualDAC) is a library of components that extends data processing capabilities in Delphi, C++Builder and Lazarus (FPC) on Windows, macOS, Linux, iOS, Android, for both 32-bit and 64-bit platforms. VirtualDAC consists of components that provides such capabilities as working with non-tabular data, performing SQL-queries to data in memory or to data from sources in different RDBMS'es etc., that are not available for standard data access components.
The TVirtualQuery component is used to retrieve data with SQL queries from sources, that are any TDataSet descendants. Due to this, you can build complex SQL queries to in-memory data (data sources are TVirtualTable, TVirtualDataSet or another TVirtualQuery) or to data stored in different RDBMS'es (data sources can be TUniQuery, TOraQuery, TMSQuery, TMyQuery, etc. at the same time).
The TVirtualTable component represents an in-memory data storage that does not have linked data files. TVirtualTable allows to load data from a XML file, or from an existing dataset, and then process the data in the usual way, as in any TDataSet descendant.
The TVirtualDataSet component is data wrapper that doesn't store data in memory and interacts with data using event handlers. It allows to represent arbitrary data (arrays, lists, objects, etc.) as TDataSet descendants and link it with any DB-aware components to display data or modify it.
The TVirtualTable component represents an in-memory data storage that does not have linked data files. TVirtualTable allows to load data from a XML file, or from an existing dataset, and then process the data in the usual way, as in any TDataSet descendant.
The TVirtualDataSet component does not store data in memory and interacts with data using event handlers. It can be used to represent of arbitrary data (arrays, lists etc.) in tabular form, and for modifying the data using usual TDataSet methods.
The TVirtualQuery component is used to retrieve data simultaneously from several different RDBMS'es. Instead of a database connection, it use a collection of TDataSet descendants as the data source, to which a SQL-query can be performed.
The following list describes the main features of Virtual Data Access Components.