In a system like EUEDOS DataBase Manager (DBM) the issue of data migration is critical. Indeed in many institutions EUEDOS DataBase Manager (DBM) will substitute some other database application and in such a case an as completely as possible data migration is imperative. Also it is generally admitted that in database applications, the massive data import and export is expedient if not necessary. Usually this is a laborious and error prone effort. For these reasons EUEDOS DataBase Manager (DBM) is accompanied by a relevant software that makes possible the safe, accurate and easy data exchange between databases.
The whole process of data exchange can be divided into two phases: a) Data export from the source database, b) Data import to the target database. Both data export and data import are actions completely autonomous, even though combining them as successive actions, they constitute an integrate process. As data exchange mediator we use XML document.
1) The first phase would deal with the extraction of data required to transfer from the existed database which will be superseded by EUEDOS DataBase Manager (DBM), to an intermediate file format, which will act as the mediator for data transferring. The global acceptance of XML as the most convenient medium in data sharing, indicates our choice of data exchange medium in EDOS system.
The description bellow applies to a fully on-line available application. This feature is necessary in order to implement the data export using a workstation that can connect with the database server, either locally or remotely. The process can be performed on any PC in the network or Internet, where of course the software has been installed, as presented in Fig. 3
How it works
The user acts in three major steps:
A) In the first phase the user enters the necessary parameters to connect with the database (Fig.1 upper panel). Thus:
Fig. 1
B) In the second phase the user defines precisely what he wants to export from the database. Thus:
Fig. 2
C) In the third phase the user designated the output file name and starts the process of data extraction. Thus:
Fig. 3
Fig. 4
Back
The whole process of data exchange can be divided into two phases: a) Data export from the source database, b) Data import to the target database. Both data export and data import are actions completely autonomous, even though combining them as successive actions, they constitute an integrate process. As data exchange mediator we use XML document.
1) The first phase would deal with the extraction of data required to transfer from the existed database which will be superseded by EUEDOS DataBase Manager (DBM), to an intermediate file format, which will act as the mediator for data transferring. The global acceptance of XML as the most convenient medium in data sharing, indicates our choice of data exchange medium in EDOS system.
DATA EXPORT
In this phase the required data are extracted from the existed database which will be superseded by EUEDOS DataBase Manager (DBM), to an XML document, the most ubiquitous data exchange medium with many advantages. An XML file is essentially an ASCII file containing tags, that can even be edited by any ASCII editor. On the other hand, the reading of an XML document is comprehensible even from readers that know nothing about the structure of information which is stored in XML document. Moreover the output xml file can be converted instantly to an html file through an xsl, in order to publish the results. The data export can be done according to the parameters set by the user or the database owner, to an XML file compliant with a agreed schema of data structure. In addition, considering the fact that the data export is going to take place on a regular basis (f.e., every day), the software stores optionally the parameters of a data export process, defining a project that holds these parameters. Via this method, any time the user wishes to repeat the data export, he simply loads the related project. Among many future option of this "Software bridge", is also a schedule mechanism, which will upgrade the Short descriptionThe description bellow applies to a fully on-line available application. This feature is necessary in order to implement the data export using a workstation that can connect with the database server, either locally or remotely. The process can be performed on any PC in the network or Internet, where of course the software has been installed, as presented in Fig. 3
How it works
The user acts in three major steps:
A) In the first phase the user enters the necessary parameters to connect with the database (Fig.1 upper panel). Thus:
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1. Selects the database engine type (e.g. MSSQL, MySQL, Oracle, etc.).
2. Enters the name or IP address of database server that hosts the database.
3. Enters the name of database from which we want to export data, or connects to the database server and selects one of the available databases.
4. Tests the connection with the database.
Fig. 1
B) In the second phase the user defines precisely what he wants to export from the database. Thus:
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5. Chooses either one independent table or two interrelated tables from which he wishes to export data. On Fig.2 on the middle panel, on the left list we can see all the tables of database edos2_vienna, whilst on the middle list we see the selected table to extract.
6. For each table the user chooses the exact fields she/he wants to take part in the extraction process. In the case we have interrelated tables she/he defines the relationship. That means that the user defines the pair of fields upon which the relation is based. On Fig.2 on the right list we see the selected fields of table student_professional_v to extract.
7. She/He further defines the names of the selected fields in the output (bottom panel on Fig.2). For example the field that holds the age of the students may be named as st_age, whilst in the XML file it may be desirable to name it as student_age. Then we need a mapping between the source field names and the target field names.
Fig. 2
C) In the third phase the user designated the output file name and starts the process of data extraction. Thus:
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8. Designates the name of the output file.
9. Saves the data exporting parameters to a project for future use.
10. Selects where to save the output file.
11. Starts the process of data extraction.
Fig. 3
DATA IMPORT
In this phase the data contained in the XML document are imported to EUEDOS DataBase Manager (DBM). It is technically and operationally sound, that the most convenient, effective and secure way of XML file transferring to the EUEDOS DataBase Manager (DBM) vertical database, is via an established internal service of the EDOS system. The service will be offered to the administrator from the "Administration area" through a link labeled as "Massive data import". When the administrator clicks on that link, the related service is invoked and provides a file selection process via which, the administrator can select the XML file desired to upload to the EUEDOS DataBase Manager (DBM) vertical system. After the file selection and subsequent transfer to the EUEDOS DataBase Manager (DBM) vertical system, the service calls another module charged with the XML file parsing and data import to its database. In this way, the database update takes place immediately after the XML file becomes uploaded to the EUEDOS DataBase Manager (DBM). This process is depicted in Fig.4Fig. 4