Method and device for recovering deleted records of SQLite database file

Abstract

The invention provides a method and device for recovering deleted records of a SQLite database file. The method for recovering deleted records of a SQLite database file comprises the following steps: analyzing the SQLite structure; obtaining the SQLite file encoding mode and the page size information; creating the base library of the field number and type of each table and realizing the association of the free pages with the base library; judging whether the free-block is covered or not and checking the integrity of the free-block; classifying the missing cases combined with the known data parameters which can be extracted from the free-block; and refactoring the control header information of the deleted records quickly and realizing the recovery of the SQLite deleted records. According to the invention, the base library of the field number and type of each table is created; the integrity check of the free-block is performed, so that the recovery accuracy rate is increased; the Rowid width of the free-block is calculated by means of the Rowid of the adjacent data unit that has not been deleted; the first four bytes in the memory structure of the free-block are calculated and reconstructed by means of the free-block size. Therefore, the data recovery of the SQLite deleted records can be realized generally, quickly and accurately by means of the invention, and the recovery rate and the recovery accuracy can be improved compared with the traditional method.

Description

technical field [0001] The invention relates to the field of databases, in particular to a method and a device for recovering and deleting records of SQLite database files. Background technique [0002] SQLite is a lightweight database that can support mainstream operating systems such as Windows / Linux / Unix and can be combined with many programming languages. SQLite has been widely used in embedded devices, Android devices and various application platforms with a series of characteristics such as very low resource occupation, fast processing speed, convenient use, and open source code. [0003] Because SQLite is widely used, it stores rich and diverse data information, including Android device address book, SMS, call records, WeChat / QQ chat records, and various browser Internet access records, etc. How important this amount of information is to users, once it is accidentally deleted and lost by mistake, it will often bring a lot of inconvenience to users. Similarly, in the...

AI Technical Summary

Problems solved by technology

Since the data header of the deleted record item has an indefinite length, and the data encoding method is different, the first 4 key bytes of the deleted record item are erased. It is not accurate to simply use the table field to infer the data length and locate the offset position of the data area. Whether the deleted record item is overwritten and the integrity check is performed, the number and field type of the table field to which the deleted record item belongs is not checked, resulting in the restored data containing more useless data, resulting in garbled characters

Therefore, the data recovered by the existing solutions is inaccurate, there are many invalid information and garbled characters, and the recovery rate and recovery effect are not good, which cannot meet the needs of the actual situation.

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