File Extension DCX

File type: FoxPro Database Index File

About the DCX file type:

If Windows cannot find the appropriate program associated with .DCX files, then your registry may have errors. Check your Windows registry for errors (includes file association errors).

The FoxPro Database Index file is represented by the DCX file extension for the purpose of improving the search and sort functionality of the objects contained in the database. Essentially, a database index file is considered as a type of data structure which improves the operational speed of the database table. The index file is created based on one or more columns that are part of the database table. These columns form the basis for the speedy and efficient look up of data which are accessed in an orderly manner. The storage space required by the DCX format file would largely depend on the stored data and is considerably less than the database file itself. This is because the index file essentially contains information from key fields in the database depending on how it is arranged in the table and explicitly discards all other information. This file type also makes it possible to store database indexes in system memory for database tables that are too large to fit in the available memory. The DCX file extension supports the functionality of controlling the existence of duplicate values, establishing referential integrity, optimizing indexes using logical expressions, organizing records depending on the first specific value, and optimizing the query and search operation. All types of the DCX format files except for the binary indexes can be used in performing seek, ordering, viewing, and querying operation on the existing database records. All index types however can be used for optimizing filter conditions using the WHERE and ON quantifiers for SQL SELECT instructions.


Detailed information for file extension DCX

Category: Miscellaneous Files
File format: Proprietary
Open with Windows: Microsoft Visual Foxpro
Open with Linux: N/A
The types of the DCX file extensions generated by the Visual FoxPro development language include Primary, Candidate, Regular, Binary, and Unique Indexes. The Primary type stores an index key for every record that exists within the table and is the default type used by the application. This index prohibits the use of duplicate values under the index expression or fields key used to generate the index key. This type of index is an important part of the table and is removed when the user frees the table from the database. The Candidate index is similar to the Primary variant with the difference being a user able to create multiple candidate indexes for every table. This is presented as an alternative to the Primary index selection. When a candidate index is specified and duplicate data is encountered on any of the fields, an error would be generated by the Visual FoxPro language. Regular indexes are those which are not unique, candidate, or primary. These indexes allow the existence of duplicate values in index expressions and fields. Binary indexes are created based on logical expressions like indexing of deleted records. This type of index however has no support for the evaluation of null expressions or the use of the FOR clause in filtering expressions. Unique indexes are normally used by older versions of the Visual FoxPro development language.