GB2445366A

GB2445366A - Method for preserving access to deleted documents in a document management system

Info

Publication number: GB2445366A
Application number: GB0516995A
Authority: GB
Inventors: Rajesh Kapur
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-04-14
Filing date: 2005-08-18
Publication date: 2008-07-09
Also published as: GB0516995D0; CA2506167A1

Abstract

A method for preserving access to deleted document data within a system, wherein said document data is stored in a system filestore associated with a system database containing reference data to point to the document data within the system filestore, the method comprising the steps of: ```determining that a delete command has been issued; ```recording the reference data prior to or after deleting of the reference data; ```inserting the recorded reference data in a set of access-preservation tables; and ```providing the set of access-preservation tables to point to the deleted document data within the filestore.

Description

2445366

TITLE: METHOD FOR RETRIVING DELETED DOCUMENTS

METHOD FOR RETRIVING DELETED DOCUMENTS

Many companies use document management software. The purpose of such software is to help companies keep track of large volumes of documents in an organized way, so that documents can be easily stored, found and retrieved. In many cases, there will be more than one version of a particular document. Thus, version control is another aspect of most document management systems.

Version control is an issue of particular importance in situations where different people are able to share documents. Amongst the most popular is Documentum

The document management systems typically includes a system database that is associated with a filestore. The filestore stores the actual document data, while the system database stores reference information that points to the document within the filestore. Also, the system database typically stores supplementary document information regarding each document.

As part of the management of documents, documents get deleted from the database associated with the filestore. One useful requirement is that on delete the document and all its versions can be retrieved, this process of recovering deletes is useful but the catching the deleted files is extremely, useful when applied to migration of documents out from Documentum before it runs a standard clean-up routine that makes it effectively impossible to retrieve the deleted files. Currently no system or method exists of extracting a document if required out from Documentum. One application of this would be if the company wanted to move to another documentum system, or even back to filemanager. Another to archive,

hive of documents back to storage disk.

What is required is a method for allowing users to migrate documents managed by a document management system by retrieving documents deleted intentionally and for the purpose of migration.

One aspect of the present invention provides a method for preserving access to deleted document data within a documentum system, wherein said document data is stored in a system filestore associated with a system database containing reference data to point to the document data within the system filestore, the method comprising the steps of:

determining that a delete command has been issued;

recording the reference data prior to the deleting or updating of the reference data;

inserting the recorded reference data in a set of access-preservation tables;

and

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providing the set of access-preservation tables to point to the deleted document data within the filestore.

Preferably, the reference data is contained within three system tables in the system database, and wherein the recording step comprises the step of recording reference data from said three system tables.

The system, in response to a delete command, deletes reference data from first and second system tables and updates reference data from a third system table. The system comprises a Documentum document management system, and wherein the first system table comprises a dm_sysobject_s table, the second system table comprises a dm_sysobject_r table, and the third table comprises a dmr_content_r table.

Preferably, the reference data comprises object identification data from the first table, version identification data from the second table, and a parent identification within the third table, wherein the parent identification can be joined to a fourth table which points to the document data in the system filestore.

The system comprises a Documentum document management system, wherein the fourth table comprises a dmr_content_s table.

Preferably, the recording step comprises recording the reference data using a first Oracle trigger associated with the first table, a second Oracle trigger associated with the second table, and a third Oracle trigger associated with the third table,

Preferably, the set comprises a first access-preservation table to receive reference data recorded from the first system table, a second access-preservation table to receive reference data recorded from the second system table, and a third access preservation table to receive reference data recorded from the third system table.

Preferably, the method further comprises the step of using the reference data from the access preservation data to obtain supplementary document information,

related to the deleted document, from system tables.

Preferably, the supplementary document information includes information selected from the following group: a name of the document deleted, a folder within the system database from the document was deleted, a storage identification of the deleted document that indicates the position of storage within the filestore, a parent identification of the deleted/overwritten document to permit checking of the document path within the filestore, an object identification to provide filestore path information, a type of object that was deleted, a version of the deleted document and a date that the document was deleted, together with any information attached

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or stored in attributes against the document by the user.

Preferably, the method further comprises combining the access-preservation table and the supplementary document information into a combined table. Preferably, the combining step comprises combining prior to the system executing a method that cleans the system tables to prevent access to supplementary document information for deleted documents from the system tables. Preferably, the system comprises a Documentum document management system, and wherein the method is carried out by a dm_clean routine. Preferably, the recording, inserting and providing steps are executed by the execution of Oracle software code. Preferably, the recording, inserting and providing steps are executed by the execution of SQL Server software code.

Figure 1 is a schematic diagram of a system for preserving access to deleted documents for the purposes of migration/Archiving according to a first embodiment of this invention.

Figure 1 shows a system 100 according to a first embodiment of the invention which allows the capture of relevant reference and supplementary document information at the exact time it is deleted or updated by means of three database triggers 103. These triggers 103 are added to the relevant Documentum tables 102 and they automatically fire to capture the salient information needed to retrieve the pointer information to the physical data for the file by running a stored procedure.

A typical Documentum system database 101 has a number of system tables 102 that store reference information and supplementary document information. These tables include (but are not typically limited to) the dm_sysobject_s table (first table), which stores object IDs for the documents; the dm_sysobject_r table (second table) which stores, inter alia, version IDs for documents; the dmr_content_r table (third table) which stores, inter alia, parent ID needed to find the pointer to the document within the filestore; and the dmr_content_s table (fourth table), which stores an robjectJD that, together with the parentJD, determines the pointer to the location of the document within the filestore.

When a document is deleted, the relevant reference data from the first two tables is deleted, and the relevant reference data from the third table (including the parent ID) is updated to a Null.

According to the invention, at least three, database triggers 103 are used to catch and record the reference data that was deleted. These reference data are then inserted into access-preservation tables 104 ,this access-preservation data preserved points to the deleted document within the filestore 108.

In the invention, the reference data from the access preservation tables 104 is

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used to obtain supplementary document information, related to the deleted document, from the system tables 102. The supplementary document information preferably includes a name of the document deleted , a folder within the system database 101 from which the document was deleted, a storage identification of the deleted document that indicates the position of storage within the filestore 108, a parent identification of the deleted document to permit checking of the document path within the filestore, an object identification to provide filestore path information, a type of object that was deleted, a version of the deleted document and a date that the document was deleted, together with any information attached or stored in attributes against the document by the user.

The invention further comprises the step of combining the access preservation tables 104 and the supplementary document information into at least one combined table 107. This step is preferably performed before the system executes a cleaning of the system tables, because at least some of the supplementary document information will not be available once a cleaning, such as a dm_clean routine, is run.

In typical operation, the data location within the filestore at which a document is located is obtained by combining the parent ID from the third table with the r_object_ID from the fourth table to obtain the data ticket (i.e. the pointer) along with the storage ID which can be used to find the file path of the document on the' filestore.

This pointer information can then be translated through commonly available Documentum support notes. The Data Ticket and the storagejd (pointer info)are two pieces of data that need to be obtained to help retrieve the document's physical file. The other information required is the r_object_id and the parentjd.

The actual path and filename are typically encrypted within the filestore to protect the document from unauthorized access. To decrypt, support note 310 is used and the parentjd taken from the combination tables described further below;

before dm_clean is run, the parent ID is plugged into the Documentum APIs shown on the note through the API interface in Documentum Administrator.

For example apply,c, 090106d450cgbs3b, GET PATH

next,c,q0

get,c,q0,result

This should give you the path of the file on the content store(but only works before dm_clean is run).

As described below, another Documentum support note can also be used to calculate the full file path and name of the document stored on the server. This is

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done using the r_object_id , storagejd and Datajicket (all values contained in the combination tables This alternate calculation of the file path and name can be compared with the above calculation using note 310 to increase the probability that the correct file path and name are known. Once dm_clean has been run, the note 310 calculation will not work, but the alternate calculation will function to find the exact place on the server or backup tape at which a deleted file resides. The method of the present invention can then be used from the time of successful comparison of the two name and path calculations, i.e. by running the procedures below automatically through either a Cron / or Veritas job.

When an object or document is deleted or overwritten, the parentjd of the document is updated and set to Null. Once this occurs there is no way to link the dmr_content_r table to the dmr_content_s table. The purpose of the recording of reference information was, inter alia, to ensure that the parent ID was recorded in order to get storage location and data ticket.

The invention can be implemented in a multi-database embodiment. Below is sample code, which illustrates the use of before and after row triggers to capture the data.

Oracle:-

Create or replace trigger capture_del_rjrigger before delete on dm_sysobject_r for each row Begin

Insert into capture_rjable val ues(: old. r_objectJd,: old. r_version Jabel,: old. ijolderjd);

EXCEPTION when others then RAISE;

END;

/

create or replace trigger capturejjrigger before update on dmr_content_r for each row Begin

Insert into capturejjable values(:old.r_objectJd,:old.parentJd);

EXCEPTION

When others then

RAISE;

END;

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create or replace trigger capture_del_s_trigger before delete on dm_sysobject_s for each row Begin

Insert into capture_del_s_table values

(:old.r_objectJd,:old_r_object_type,:old.object_name,SYSDATE);

EXCEPTION when others then RAISE;

END;

/

create or replace trigger capture_upd_s_trigger before update on dm_sysobject_s for each row Begin

Insert into capture_upd_s_table (r_object_id,

r_object_type,object_name,r_versionJabeU_folder_id,date_saved)

select

:old_r_objectJd,:old_r_object_type,:old.object_name,r_versionJabel,i_folderJd,sy sdate from dm_sysobject_r where r_object_id = :old.r_object_id and r_version_label != 'current';

EXCEPTION when others then RAISE;

END;

/

then Sql Server-

create trigger capture_del_r_trigger on dbo.dm_sysobject_r After Delete ~ FOR Delete as if exists (insert into capture_del_r_table values (r_object_id, r_version_label, i_folder_id)

select r_object_id, r_version_label, i_folder_id from deleted where r_object_id in (select r_object_id from deleted)

)

go

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create trigger capture_i_trigger on dbo.dmr_content_r After Update -- FOR Update as if exists (insert into capturejjable values (r_object_id, parentjd)

select r_objectJd, parentjd from deleted where r_objectJd in (select r_object_id from deleted)

)

go create trigger capture_del_sjrigger on dbo.dm_sysobject_s After Delete -FOR Delete as if exists (insert into capture_del_s Jable values (r_objectJd, r_objectJype, object_name,date_saved)

select r_objectJd, r_object_type, object_name,getdate() from deleted where r_objectJd in (select r_object_id from deleted)

)

go

In the the dm_sysobject_s and dm_sysobject_r tables, a "before row delete" is preferably used, meaning the data the is about to be deleted is captured. For the dmr_content_r table, a "before update row" is preferably used, meaning that the data to be updated is captured. This ensures that all salient and/or relevant information is captured.

It will be appreciated that an "after row delete" and "after row update" could also be used and are comprehended by the invention. In such a case, the old values are captured immediately upon the deletion or update.

The reference data is trapped (i.e. recorded) and inserted into three tables:-

create table capturejJable (

robjectjd varchar2(16),

parentjd varchar2(32),

date_saved date)

/

create table capture_del_s Jable (

r_objectJd varchar2(16),

r_objectJype varchar2(32),

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object_name varchar2(255), date_saved date)

/

create table capture_del_rJable (

r_object_id varchar2(16),

r_version_label varchar2(32),

i_folder_id varchar2(16))

/

More columns for extra data can of course be added to these tables, but the preferred method comprises recording the salient reference data from three tables.

The procedure, given the name capture_del_data.plb is used to combine the three access-preservation tables with the dmr_content_s table to produce the combination tables and to get the all important datajicket value which must be converted to a char using to_char(data Jicket) as well as combining other data as described above to obtain a location of the encrypted file.

The combination table for deletes.

create table date_deleted storagejd data_ticket full_format r_object_id r_object_type object_name capture_del_ro_table ( date,

varchar2(16), varchar2(20), varchar2(64), varchar2(16), varchar2(32), varchar2(255), r_version_label varchar2(32), r_parent_id varchar2(32), r_folder_path varchar2(255))

/

Once the storagejd , datajicket, r_objectJd , parentjd are available in the above tables the method of the present invention is preferably every night and just before dm_clean runs. This will ensure that all of the necessary reference data is captured.

The following is the "alternate" process referred to above for calculating the file path and name. Take the storagejd obtained and use it as the r_objectJd into the table dm_store_s. This should give you the filestore concerned (there could be more than one filestore, which collectively act as the "filestore" for the document management system. The path of the filestore can be found through the Documentum administrator

Part of the file path on the filestore is stored as a hex code. The first part of this

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hex code is usually contained within the r_object_id of the deleted row corresponding to the deleted document. The remainder of the filepath can be obtained by converting the data_ticket from dec to hex using the dword function on the standard scientific calculator on Microsoft windows, as the support notes will indicate.

For example if you have a data ticket say -2147561899 this converts into

75FECE55...i.e the path to the file could look something like this c:\filestore1\documentum\docbase_name\00\06d450\75\FE\CE\55 where 55 is the file name on the server and 0006d450 comes from the r_object_id.

Once the formula for the file paths has been worked out by comparing with the above API method then a plsql routine could even be written to give this automatically.

Basically once the path is known and the date is known, the document that was deleted can be retrieved from a Backup tape if it has been cleaned off the server. This is because the path and name are known, so the tape copy of the filestore can be used to locate the deleted file.

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Claims

CLAIMS:

1. A method for preserving access to deleted document data within a system, wherein said document data is stored in a system filestore associated with a system database containing reference data to point to the document data within the system filestore, the method comprising the steps of:

determining that a delete command has been issued;

recording the reference data prior to or after the deleting of the reference data;

inserting the recorded reference data in a set of access-preservation tables;

and providing the set of access-preservation tables to point to the deleted document data within the filestore.

2. A method as claimed in claim 1, wherein the reference data is contained within three system tables in the system database, and wherein the recording step comprises the step of recording reference data from said three system tables.

3. A method as claimed in claim 2, wherein the system, in response to a delete command, deletes reference data from first and second system tables and updates reference data from a third system table.

4. A method as claimed in claim 3, wherein the system comprises a Documentum document management system, and wherein the first system table comprises a dm_sysobject_s table, the second system table comprises a dm_sysobject_r table, and the third table comprises a dmr_content_r table.

5. A method as claimed in claim 3 or claim 4, wherein the reference data comprises object identification data from the first table, version identification data from the second table, and a parent identification within the third table, wherein the parent identification can be joined to a fourth table which points to the document data in the system filestore.

6. A method as claimed in claim 5, wherein the system comprises a Documentum document management system and wherein the fourth table comprises a dmr_content_s table.

7. A method as claimed in any one of claims 1 to 6, wherein the recording step corpprises recording the reference data using at least one Oracle trigger.

II

8. A method as claimed in any one of claims 3 to 6, wherein the recording step comprises recording the reference data using a first Oracle trigger associated with the first table, a second Oracle trigger associated with the second table, and a third Oracle trigger associated with the third table.

9. A system according to claim 7 or claim 8, wherein the combination table comprises deleted data.The system as substantially herein described with reference to the accompanying drawing.

/~7

9. A method as claimed in claim 3 or claim 5, wherein the set comprises a first access-preservation table to receive reference data recorded from the first system table, a second access-preservation table to receive reference data recorded from the second system table, and a third access preservation table to receive reference data recorded from the third system table.

10. A method as claimed in claim 1, 3 or 9, wherein the method further comprises the step of using the reference data from the access preservation table to obtain supplementary document information, related to the deleted document, from system tables.

11. A method as claimed in claim 10, wherein the supplementary document information includes information selected from the following group: a name of the document deleted , a folder within the system database from the document was deleted , a storage identification of the deleted document that indicates the position of storage within the filestore, a parent identification of the deleted document to permit checking of the document path within the filestore, an object identification to provide filestore path information, a type of object that was deleted a version of the deleted document and a date that the document was deleted.

12. A method as claimed in claim 10 or claim 11, wherein the method further comprises combining the access-preservation table and the supplementary document information into a combined table.

13. A method as claimed in claim 12, wherein the combining step comprises combining prior to the system executing a method that cleans the system tables to prevent access to supplementary document information for deleted documents from the system tables.

14. A method as claimed in claim 13, wherein the system comprises a Documentum document management system, and wherein the method is carried out by a dm_clean routine.

15. A method as claimed in any one of claims 1 to 14, wherein the recording, inserting and providing steps are executed by the execution of Oracle software code.

16. A method as claimed in any preceding claim, wherein the recording, inserting

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and providing steps are executed by the execution of SQL Server software code.

17. A system for preserving access to deleted or overwritten document data, comprising:

a database for storing reference information and supplementary document information;

at least one trigger for catching and recording reference data that has been deleted and/or updated from the database;

at least one access preservation table for storing access preservation data, the access preservation data being operable to point to the data that has been deleted and/or updated; and at least one stored procedure to combine data captured in the at least one combination table.

18. A system according to claim 17, wherein the database comprises a filestore.

19. A system according to claim 17 or claim 18, further comprising at least one system table provided in the database for storing the reference data and supplementary document information.

20. A system according to claim 19, wherein the at least one access preservation table corresponds to the at least one system table.

21. A system according to any one of claims 17 to 20, further comprising storage identification means for indicating position of storage within the filestore.

22. A system according to any one of claims 17 to 21, further comprising object identification means.

23 A system according to any one of claims 17 to 22, further comprising at least one combination table.

24. A system according to claim 23, further comprising at least one data combination means operable to combine the at least one access preservation table and the supplementary document information into the at least one combination table.

25. A system according to claim 23 or claim 24, wherein the combination table comprises deleted data.

26. A system according to claim 23 or claim 24, wherein the combination table comprises data deleted on purpose for purposes of migration or archiving.

27. A system according to claim 23 or claim 24, wherein the combination table

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comprises deleted data.

28. The system as substantially herein described with reference to the accompanying drawing.

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Amendments to the claims have been filed as follows

1. A method for preserving access to deleted final documents within a system, to allow their identification, separation and manual migration to other document management systems or to conventional systems and or manual archival in case the document is deleted for said purpose , wherein said document is stored in a system filestore associated with a system database or store that contains reference data to point to the document data within the system filestore, the method comprising the steps of:

determining that a delete command has been issued;

recording the reference data prior to or after the deleting or updating of the reference data;

inserting the recorded reference data into a newly added access preservation store or table; and combining and separating final deleted documents from any overwritten documents by means of manual run procedure(s)

, to combine all other salient reference data connected with the reference data before system reference and documents are cleaned; and providing at least one access preservation or combination table to hold the metadata pointing to the deleted documents awaiting storage or transfer.

2. A system for preserving access to deleted document data, for the purpose of migration or mantjgi archival comprising:

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a database for storing reference information and supplementary reference document information;

a filestore storing the physical encrypted file on which the reference data is kept;

at least one database trigger for catching and recording and separating out reference data that has been deleted and/or updated from the database;

at least one access preservation table for storing access preservation data, the access preservation data being operable to point to the data that has been deleted and/or updated; and at least one procedure to combine data captured in the at least one combination preservation table.

3. A system according to claim 2, comprising at least one system table provided in the database for storing the reference data and supplementary document information.

4. A system according to claim 2, wherein the at least one access preservation table corresponds to the at least one system table.

5. A system according to any one of claims 2 to 4, further comprising storage identification means for indicating position of storage within the filestore.

6. A syatefn according to any one of claims 2 to 5, further comprising object identification means.

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7. A system according to any one of claim 2, further comprising at least one combination table.

8. A system according to claim 7, further comprising at least one data combination means operable to combine and separate the data in at least one access preservation table and the supplementary document information in the system in regards to the rows into the at least one combination table.