What Is a Data File?
In a bulk copy operation, data is transferred from an outward bulk copy operation to an inbound bulk copy operation. In a SQL Server 2000 database, a data file stores the data stored in the database. Each SQL Server 2000 database has at least one primary data file, and there can be multiple secondary data files to hold data that is not suitable for placement in the primary data file. There are many data files, and the concept of data is relatively broad. Graphics, sound, numbers, and various code systems are data. The files that store these data are data files.
- The primary data file consists of the initial data files in the primary file group. A file group is a named collection of data files. Contains all database system tables, as well as objects and data that are not assigned to custom filegroups. The main data file is the starting point of the database, which points to other files in the database. Each database has a primary data file and a primary file group. The extension of the primary data file is .mdf.
- on primary-belongs to the primary file group by default and can be omitted
- (
- / *-Specific description of the data file-* /
- name = 'Database Name_data',-the logical name of the main data file
- filename = 'Saved location: \ database name_data.mdf',-the physical name of the master data file
- size = value mb,-initial size of the main data file
- maxsize = value mb,-the maximum growth of the master data file
- filegrowth = value%-growth rate of the master data file
- )
- When performing hard disk data recovery, if you scan from beginning to end every time, it takes a lot of time, and most of the recovered data is unnecessary. To save time and increase efficiency, specific important data files should be recovered. Based on the principles of hard disk startup and file reading and writing, analyze the operation of the operating system when the file is modified or deleted, and compare and analyze the changes of the file allocation table (FAT) and file directory table (FDT) when a specific file is modified or deleted To solve the problem that the existing data recovery technology cannot automatically recover discontinuous cluster files, specific file recovery is performed through the distribution rule of continuous clusters in the FAT table. [1]
- The data file formats in 3D printing are mainly divided into 2 categories: CAD 3D data file formats and 2D layer file formats. CAD 3D data file formats include: STL (stereolithography), STEP (standard for the exchange of product modal data), IGES (initial graphics exchange specification), LEAF (layer exchange ASCII format), RPI (rapid prototyping interface), LMI (layer manufacturing interface), etc .; The two-dimensional layer file formats include: SLC (stereo lithographycontour), CLI (common layer interface), HPGL (Hewlett-Packard graphics language) and so on. Among them, STL is the earliest file format used for data exchange between CAD and CAPP, and has been widely used. Currently, most 3D printing systems are designed based on the STL format. [2]