CN101430705A - Memory method and apparatus based on embedded database - Google Patents

Abstract

The invention discloses a storage method and device based on an embedded database, wherein the method includes: presetting a first storage area and a second storage area on a memory, wherein the memory is used to store data of the embedded database; Multiple sets of data in the embedded database are updated, and each set of updated data is stored in the first storage area; if the updated multiple sets of data are successfully stored in the first storage area, the first Multiple sets of data stored in the storage area are copied to the second storage area. With the help of the technical solution of the present invention, by setting two storage areas on the memory and storing the data in these two areas respectively, it is ensured that the system can recover when a serious error occurs during the storage process, and the error data can be monitored where it happened.

Description

Storage method and device based on embedded database

technical field

The invention relates to the communication field, in particular to a storage method and device based on an embedded database.

Background technique

The embedded database is stored in the storage in units of tables. If you want to modify the data in the embedded database in the memory, you need to save the new data to the storage again. However, during the process of saving the new data to the storage, if the system crashes Power-on or reset will cause some new data and some old data to be stored in the memory, which will destroy the consistency of the data.

At present, XML is mainly used to store data. The past method is to save the new data in an intermediate format to the memory after modifying a table, and then rename the intermediate format file to an XML file. If 3 tables are modified at the same time, when the 1st and 2nd tables are all saved, and the system resets when the 3rd table is saved, then the data of the 1st and 2nd tables are modified, and the data of the 3rd table is modified previous. This cannot guarantee the consistency and correctness of the embedded database data.

Contents of the invention

In consideration of the problems existing in the related art in the data storage process of the embedded database, the consistency and correctness of the embedded database data cannot be guaranteed and the present invention is proposed. For this reason, the main purpose of the present invention is to provide a A storage method and device for a database to solve the above problems.

According to one aspect of the present invention, a storage method based on an embedded database is provided.

The storage method based on the embedded database according to the present invention includes: presetting the first storage area and the second storage area on the memory, wherein the memory is used to store the data of the embedded database; updating multiple sets of data of the embedded database operation, and, for each set of data that has been updated, store them in the first storage area; if the multiple sets of data that have been updated are all successfully stored in the first storage area, copy the multiple sets of data stored in the first storage area to the second storage area.

Further, the method further includes: if storing the multiple sets of data in the first storage area fails, re-updating the multiple sets of data of the embedded database.

In addition, before performing the update operation, the method also includes: presetting a first flag indicating to store the modified multiple sets of data in the first storage area, and instructing to store the modified multiple sets of data in the first storage area To the second identification under the second storage area; storing the multiple sets of data modified in the embedded database into the first storage area includes: writing the first identification in the memory, and storing the multiple sets of data modified in the embedded database Stored in the first storage area; copying the multiple sets of data stored in the first storage area to the second storage area includes: writing the second identification in the internal memory, and copying the multiple sets of data stored in the first storage area to the second storage area.

Preferably, after writing the first identification, the method further includes: calculating and saving the check code corresponding to the first identification, and copying the first identification and the check code corresponding to the first identification to the memory; After the second identification, the method further includes: writing the second identification in the memory to cover the first identification, calculating and saving the verification code corresponding to the second identification, and copying the second identification and the verification code corresponding to the second identification Overwrite the first identifier and the check code corresponding to the first identifier in the memory.

Further, the method further includes: reading the current identification in the memory, and calculating the reference check code of the read identification, and if the calculated reference check code is consistent with the check code corresponding to the identification stored in the memory, then reading Get the storage area indicated by the identifier, where the identifier is the first identifier or the second identifier.

Wherein, if the reference check code read in the memory is inconsistent with the check code corresponding to the logo, the method further includes: reading the current logo in the memory, and calculating the reference check code of the read logo, if the calculated The reference check code is consistent with the check code corresponding to the identifier stored in the memory, and then the storage area indicated by the identifier is read, wherein the identifier is the first identifier or the second identifier.

Further, the above method also includes: respectively setting corresponding data identifiers for multiple sets of data, and the data identifiers are written into the memory when the corresponding data is stored in the first storage area and overwrite the previously written data identifiers; When storing the updated multiple sets of data in the first storage area fails, the data identification is read from the memory, and the data of the read data identification is determined as the data that fails to be stored.

According to another aspect of the present invention, a storage device based on an embedded database is provided.

The storage device based on the embedded database according to the present invention includes: a first setting module, which is used to pre-set the first storage area and the second storage area on the memory, wherein the memory is used to store data of the embedded database; an update module, It is used to update multiple sets of data in the embedded database, and each set of updated data is stored in the first storage area; the processing module is used to successfully store multiple sets of updated data in the first storage When the area is selected, multiple sets of data stored in the first storage area are copied to the second storage area.

Further, the device further includes: a second setting module, configured to set a first flag indicating to store the modified multiple sets of data in the first storage area, and indicate to store the modified multiple sets of data in the first storage area The second identification stored in the second storage area; the writing module is used to write the first identification and/or the second identification in the memory; correspondingly, the processing module is used to write multiple sets of data modified in the embedded database Store in the first storage area, and/or copy multiple sets of data stored in the first storage area to the second storage area.

Through at least one of the above-mentioned technical solutions of the present invention, by setting two storage areas on the memory and storing data in these two areas respectively, it is ensured that the system can be restored when a serious error occurs during the storage process, and can monitor The location where the erroneous data occurred.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the attached picture:

Fig. 1 is the flow chart of the storage method based on embedded database according to the method embodiment of the present invention;

Fig. 2 is the processing flowchart of the data storage procedure according to the method embodiment of the present invention;

Fig. 3 is the processing flowchart of the data loading process according to the method embodiment of the present invention;

Fig. 4 is the structural block diagram of the storage device based on embedded database according to the device embodiment of the present invention;

Fig. 5 is a preferred structural frame diagram of the storage device based on the embedded database according to the device embodiment of the present invention.

Detailed ways

Functional Overview

As described above, the correctness of the data is very important to the embedded database. After the data is rewritten in the memory, if the rewritten data cannot be stored in the memory correctly, the system will load the wrong data when it is loaded again. data, resulting in system errors. Based on this, the present invention provides a structure using double directories to ensure that the system can be rolled back even if an error occurs during the data storage process, and three identification files are added to mark the location of the error during the system storage process, which is convenient for System error in positioning.

The term "storage medium" may refer to one or more devices for storing data, including read-only memory (ROM), random-access memory (RAM), magnetic RAM, magnetic core memory, magnetic disk storage media, optical storage media, flash memory device and/or other machine-readable medium for storing information. The term "machine-readable medium" includes, but is not limited to, portable or fixed storage devices, optical storage devices, wireless channels, or various other media capable of storing, containing, or carrying instructions and/or data.

Additionally, embodiments may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or combinations thereof. When implemented in software, firmware, middleware or microcode, the program code or code segments for performing the necessary tasks may be stored in a machine-readable medium such as a storage medium. The processor(s) can perform the necessary tasks. A code segment may represent a process, function, subroutine, program, routine, subroutine, module, object, software package, class, or any combination of instructions, data structures, or programming languages. A code segment is coupled to another code segment or a hardware circuit by transmitting and/or receiving information, data, arguments, or stored content. Information, arguments, parameters, data, etc. may be communicated, transmitted, or communicated via any suitable means including memory sharing, message passing, token passing, network transmission, and the like.

In the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

The present invention will be described in detail below with reference to the accompanying drawings.

method embodiment

According to an embodiment of the present invention, a storage method based on an embedded database is provided.

It should be noted that, for the convenience of description, the technical solutions of the method embodiments of the present invention are shown and described below in the form of steps, and the steps shown below can be executed in a computer system such as a set of computer-executable instructions implement. Although a logical order is shown in the associated figures, in some cases the steps shown or described may be performed in an order different from that herein.

Fig. 1 is the flowchart of the storage method based on embedded database according to the embodiment of the present invention, as shown in Fig. 1, this method comprises the following steps (step S102 to step S106):

Step S102, presetting a first storage area and a second storage area on the memory, wherein the memory is used to store data of the embedded database;

Step S104, performing an update operation on multiple sets of data in the embedded database, and storing each set of updated data in the first storage area;

Step S106, if the updated multiple sets of data are successfully stored in the first storage area, copy the multiple sets of data stored in the first storage area to the second storage area; if the multiple sets of data are stored in the first storage area If it fails in the region, it will re-update multiple sets of data in the embedded database.

In the specific implementation process, the first flag indicating to store the modified multiple sets of data in the first storage area can be preset, and the modified multiple sets of data in the first storage area can be stored in the second storage area. In this way, storing the multiple sets of data modified in the embedded database into the first storage area includes: writing the first identifier in the memory, and storing the multiple sets of data modified in the embedded database into the first storage area. In the storage area, calculate and save the check code corresponding to the first identification, and copy the first identification and the check code corresponding to the first identification to the memory; copy the multiple sets of data stored in the first storage area to the second The storage area includes: writing the second identification in the memory, writing the second identification in the memory to cover the first identification, calculating and saving the check code corresponding to the second identification, and storing the second identification and the corresponding The verification code is copied into the memory to cover the first identification and the verification code corresponding to the first identification, and multiple sets of data stored in the first storage area are copied to the second storage area.

When the system is powered on, read the current logo in the memory, and calculate the reference check code of the read logo, if the calculated reference check code is consistent with the check code corresponding to the logo stored in the memory, then read the logo The indicated storage area, wherein the identification is the first identification or the second identification, if the reference check code read in the memory is inconsistent with the check code corresponding to the identification, read the current identification in the memory, and calculate the read The reference check code of the identification, if the calculated reference check code is consistent with the check code corresponding to the identification stored in the memory, read the storage area indicated by the identification, wherein the identification is the first identification or the second identification.

Through the technical solution provided by the embodiment of the present invention, by setting two storage areas on the memory and storing data in these two areas respectively, it is ensured that the system can be restored when a serious error occurs during the storage process, and can monitor The location where the erroneous data occurred.

The embodiment of the present invention will be described in detail below. In the specific implementation process, it is mainly divided into file organization process (corresponding to the above-mentioned step S102), data storage (corresponding to the above-mentioned step S104) and data loading (corresponding to the above-mentioned step S104). S106) Three processes, each process will be described below.

First, the file organization process

About storage: Add two flat directories under the system's running directory, one directory is used to save the current data, called the backup directory (that is, the first storage mentioned above), and the other directory is used to save the backup data , becomes the current directory (that is, the second storage described above).

Regarding the reserved memory (that is, the memory mentioned above): set the flag bit, and judge whether the system loads data from the current directory or from the backup directory according to the system flag bit of the flag file. Open up an area on the reserved memory of the system to save the logo file of the saving process, and save a copy of the data of the embedded database in binary form under the running directory. Under normal circumstances, the copy of the data saved in the backup directory and the current directory is the same as Keep the data content in the memory exactly the same. Among them, the cyclic redundancy check (Cyclic Redundancy Check, referred to as CRC) check value is saved in the reserved memory, the total number of tables in the embedded database, the flag bits set above, and the flag bits stored in each table data (i.e., the data flags described above).

Second, the data storage process

The entire data storage process is divided into three stages in advance: the first stage is the initial stage, and the data is stored, in which, no error occurred in the last process of storing data, and the data stored in the reserved memory is correct data; The second stage is the saving stage, saving the data to be updated to the backup directory; the third stage is the copying stage, copying the successfully updated data in the backup directory to the current directory.

The system provides an interface for storing data, which can store single tables and batch tables in units of collections. Since the maximum number of tables currently supported by the system is 256, the set has 256 bits, and each bit represents a table. If a certain table needs to be saved, the corresponding bit is set to valid. The function body will parse this collection to determine which tables need to be saved.

In the specific implementation process, the system flag and the flag position of the table to be saved are the first stage, and the data in the memory is saved to the backup directory in XML data format. After saving a table, the table's The flag position is the second stage, that is, the table that has successfully saved the data to the backup directory. If an error occurs during the process of storing the table to the backup directory, the flag of the table is the first stage, that is, the data has not been saved to the backup directory. Back up the tables in the directory. After all the tables that need to be saved have been saved, the system identifies the position as the third stage. Copy the data on all the tables that need to be saved from the backup directory to the current directory. If a table is copied successfully, the corresponding table will be marked as the first stage. If an error occurs during the process of copying the table from the backup directory to the current directory , the flag bit of the table is the third stage, that is, the table that has not copied data from the backup directory to the current directory, when all the tables have been successfully copied, the system flag position is set to the first stage, and the storage process ends.

The data storage process is described below in conjunction with FIG. 2 .

Step S201, first read the system flag, judge the stage of the data storage process according to the system flag, if the flag is not normal, it means that the system has an error in the last save. If the system flag bit is used to indicate the system flag bit of the initial stage, then enter step S202, if the system flag bit is used to indicate the system flag bit of the second stage, then enter step S209, if the system flag bit is used to indicate the second stage Indicate the system flag bit of the third stage, then enter step S210;

Step S202, writing the system flag bit used to indicate the second stage;

Step S203, judging whether there are tables to be saved, if the judging result is yes, go to step S204, otherwise go to step S205;

Step S204, save all the modified data to the backup directory, and write into the system flag for indicating the third stage;

Step S205, writing the system flag bit used to indicate the third stage;

Step S206, judging whether there are tables to be copied, if the judging result is yes, go to step S207, otherwise go to step S208;

Step S207, copy the data to the current directory, and write the system flag for indicating the first stage;

Step S208, write the system flag bit used to indicate the first stage;

Step S209, if the read system flag is the second stage, it means that an error occurred when saving the data to the backup directory, it is necessary to restore the wrong data first, save the error table to the backup directory, and then copy the table Go to the current directory, that is, copy the table marked as the second stage in the identification file from the backup directory to the current directory, and modify the identification file accordingly;

In step S210, if the read system flag is the third stage, it means that an error occurred when copying data to the current directory, and the table in which the error occurred is copied to the current directory again. Then start the save process, first set the logo position of the logo file as the second stage, save the data to the backup directory, put the logo file in the third stage, copy the data from the backup directory to the current directory, and finally set the logo file as the first stage.

The third process, data loading process

Data loading is judged according to the system flag bit in the flag file. If the system flag bit of the flag file is the first stage and the second stage, it indicates that the available complete data is in the current directory. At this time, the data in the current directory is loaded. If the system flag bit of the flag file is the third stage, it indicates that the available complete data is in the backup directory, and the data in the backup directory is loaded at this time; if the flag file does not exist, the flag file is initialized to the first stage, and the corresponding directory is loaded The data. Synchronization of the three logo files, since the three logo files are equal under normal circumstances, no matter which logo file is operated, it must be synchronized to the other two logo files. When the database is powered on, it will provide a function for selecting a logo file. This function does not have parameters, and its function is to select a valid file from the three logo files. The principle of selection is to reserve the system flags stored in the memory first, and then judge the copies of the other two flag files. The specific process is as follows: first, judge whether the system flags in the reserved memory are valid through CRC check, because if there is When the system is powered off, the content in the reserved memory will be rewritten randomly. If the flag bit saved in the reserved memory is valid, the system can judge whether the system loads data from the current directory or the backup directory according to the flag bit of the flag file saved in the reserved memory. If the content of the reserved memory is invalid, judge the copy of the reserved memory. If the copy is valid, load the data according to the system flag bit of the flag file copy. If both the reserved memory and its copy are invalid, reinitialize the reserved memory and the copy of the reserved memory. Both are initialized to the first stage.

The data loading process will be described below with reference to FIG. 3 .

Step S301, judging whether the flag file exists, if the judging result is yes, go to step S302, otherwise go to step S305;

Step S302, read the storage flag bit of the flag file;

Step S303, the flag bit is the first stage and the second stage;

Step S304, loading data from the current directory of the system;

Step S305, creating a flag file and initializing it as the first stage of the stored procedure;

Step S306, loading data from the backup directory of the system.

Device embodiment

According to an embodiment of the present invention, a storage device based on an embedded database is provided.

FIG. 4 shows a schematic diagram of a storage device based on an embedded database according to an embodiment of the present invention. As shown in FIG. 4 , the device includes a setting module 10 , an updating module 20 and a processing module 30 .

The first setting module 10 is used to pre-set the first storage area and the second storage area on the memory, wherein the memory is used to store the data of the embedded database; the update module 20 is connected to the first setting module 10 and is used for Multiple sets of data in the embedded database are updated, and each set of data that completes the update is stored in the first storage area respectively; the processing module 30 is connected to the first setting module 10 and the update module 20, and is used to complete the update. When multiple sets of data are successfully stored in the first storage area, the multiple sets of data stored in the first storage area are copied to the second storage area.

Fig. 5 shows a preferred structural frame diagram of a storage device based on an embedded database according to an embodiment of the present invention. As shown in Fig. 5, on the basis of the device shown in Fig. 4, the device also includes a second setting module 40 and Write module 50.

The second setting module 40 is used to set the first flag indicating to store the modified multiple sets of data under the first storage area, and indicate to store the modified multiple sets of data in the first storage area under the second storage area The second identification of; write module 50, be connected to the second setting module 40, be used for writing the first identification and/or the second identification that the second setting module 40 sets in memory; Processing module 30, be connected to write A module 50, configured to store multiple sets of data modified in the embedded database into the first storage area after the writing module 50 writes the first identification, and/or after the writing module 50 writes the second identification, Multiple sets of data stored in the first storage area are copied to the second storage area.

Through the storage device based on the embedded database provided by the embodiment of the present invention, by setting up two storage areas on the memory and saving the data in these two areas respectively, it is ensured that the system can be restarted when a serious error occurs during the storage process. recovery, and can monitor where erroneous data occurs.

As mentioned above, with the help of the storage method and/or device based on the embedded database provided by the present invention, by setting two storage areas on the memory and storing the data in these two areas respectively, it is guaranteed that the system can save data during the storage process. It can be recovered when a serious error occurs in the system, and it can monitor the location of the wrong data. For example, if two sets of data are saved in the electronic disk, if an error occurs during the process of saving the data, the data can be rolled back; the new logo file for saving can indicate the step where the error occurred in the storage process, and the error table .

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. the storage means based on embedded database is characterized in that, comprising:

Set in advance first storage area and second storage area on storer, wherein, described storer is used to store the data of embedded database;

Multi-group data to described embedded database upgrades operation, and, for every group of data finishing renewal, store described first storage area respectively into;

All successfully store described first storage area into if will finish the multi-group data of renewal, then the described multi-group data of storing in described first storage area is copied in described second storage area.

2. method according to claim 1 is characterized in that, described method also comprises:

If described multi-group data stored in described first storage area fail, then again the multi-group data of described embedded database is upgraded operation.

3. method according to claim 1 and 2 is characterized in that, upgrades before the operation, and described method also comprises:

Set in advance the described multi-group data that indication will revise and store the sign of first under described first storage area into, and indication will the amended described multi-group data in described first storage area be stored second under described second storage area into and identified;

The described multi-group data of revising in the described embedded database stored in described first storage area comprises:

In internal memory, write described first sign, and the described multi-group data of revising in the described embedded database is stored in described first storage area;

The described multi-group data of storing in described first storage area copied in described second storage area comprises:

In described internal memory, write described second sign, and the described multi-group data of storing in described first storage area is copied in described second storage area.

4. method according to claim 3 is characterized in that, after described first sign of said write, also comprises:

Calculate and preserve the described first sign corresponding check sign indicating number, and described first sign and the described first sign corresponding check sign indicating number are copied in the described storer.

5. method according to claim 3 is characterized in that, after described second sign of said write, also comprises:

In described internal memory, write described second sign and cover described first sign, calculate and preserve the described second sign corresponding check sign indicating number, and described second sign and the described second sign corresponding check sign indicating number are copied to described first sign of covering and the described first sign corresponding check sign indicating number in the described storer.

6. method according to claim 3 is characterized in that, described method also comprises:

Read sign current in the described internal memory, and calculate the reference check code of the described sign read, if that calculates is described consistent with reference to the described sign corresponding check sign indicating number of storing in check code and the described internal memory, then read the indicated storage area of described sign, wherein, described described first sign or described second sign of being designated.

7. method according to claim 6 is characterized in that, if in described internal memory, read described inconsistent with reference to check code and described sign corresponding check sign indicating number, described method also comprises:

Read sign current in the described storer, and calculate the reference check code of the described sign read, if that calculates is described consistent with reference to the described sign corresponding check sign indicating number of storing in check code and the described storer, then read the indicated storage area of described sign, wherein, described described first sign or described second sign of being designated.

8. method according to claim 3 is characterized in that, described method also comprises:

For described multi-group data is provided with corresponding Data Identification respectively, described Data Identification when its corresponding data are stored in first storage area, be written to described internal memory and cover before the Data Identification that writes;

When the multi-group data that will finish renewal stores the failure of described first storage area into, reading of data sign from described internal memory, and the data of the described Data Identification that will read are defined as storing the data of failure.

9. the memory storage based on embedded database is characterized in that, comprising:

First is provided with module, is used for setting in advance on storer first storage area and second storage area, and wherein, described storer is used to store the data of embedded database;

Update module is used for the multi-group data of described embedded database is upgraded operation, and, for every group of data finishing renewal, store described first storage area respectively into;

When processing module, the multi-group data that is used to finish renewal all successfully store described first storage area into, the described multi-group data of storing in described first storage area is copied in described second storage area.

10. device according to claim 9 is characterized in that, described device also comprises:

Second is provided with module, be used to be provided with the described multi-group data that indication will revise and store the sign of first under described first storage area into, and indication will the amended described multi-group data in described first storage area be stored second under described second storage area into and identified;

Writing module is used for writing described first sign and/or described second sign at internal memory;

Described processing module is used for the described multi-group data that described embedded database is revised is stored in described first storage area, and/or the described multi-group data of storing in described first storage area is copied in described second storage area.

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