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Module of the subsystem "DB" <FireBird>

Module: FireBird
Name: DB FireBird
Type: DB
Source: bd_FireBird.so
Version: 1.4
Author: Roman Savochenko, Maxim Lysenko (2009)
Description: DB module. It provides the support for DB FireBird.
License: GPL

Оглавление

Introduction

Module <FireBird> gives the system OpenSCADA support of DB FireBird and InterBase. DB FireBird is a small, embedded database, with the functions of a network database that supports SQL-queries. DB FireBird is built on a commercial DBMS Interbase and distributed under a free license. To familiarize with the DBMS it is possible on the website http://www.firebirdsql.org. The module is based on the library with API of the manufacturer of DBMS on the language "C". The module allows you to perform operations over databases, tables and contents of tables.

1. Operations over the database

The operations of opening and closing of the database is supported, with the possibility of creating a new database when you open and delete existing at the close. In terms of the subsystem "DB" of system OpenSCADA opening of DB is its registration for further using of it in the system. It also supported the operation of requesting the list of tables in the database.


DB FireBird is addressed by specifying the database file name, user name and password. In general, the address database is written in this way: "{file};{user};{pass}[;{conTm}]". Where:

2. Operations over the table

The operations of opening and closing of the table with the possibility of creating a new table when you open and deleting the existing one at the closing, and also the operation of the requesting of the table's structure are supported.

3. Operations over the contents of the table


API of subsystem “DB” suppose the access to the contents of the table on the value of key(s) fields. Thus, the operation of request of the record implies the preset of key columns of the object TConfig, which will fulfill the request. Creating a new record(string) is the installation of the values of record, which does not exist.


The module allows you to dynamically change the structure of the database tables FireBird. Thus, in the event of a discrepancy of the table and the structure determined by record, the structure of the table will be set to the required structure of record. In the case of the request of the value of the record, and mismatching of the structures of record and the table there will be available only to the values of common elements of the record and table. The module does not track the order of the elements in the record and in the structure of the table!


The module is implement support multilanguage text variables. For fields with multilanguage text variable create the column of separated language in format <lang>#<FldID> (en#NAME). In this time the base column contain value for base language. The columns of separated languages created by needs, in time saving to DB and execution OpenSCADA in correspond language. If for work language value no present then will used value for base language.


The types of the elements of DB FireBird correspond to types of elements of system OpenSCADA in the following way:

The types of fields of the system OpenSCADATypes of fields of database FireBird
TFld::StringVARCHAR, BLOB SUBTYPE TEXT
TFld::IntegerINTEGER
TFld::RealDOUBLE
TFld::BooleanSMALLINT

4. DB access

Access rights to the database are defined by the rights to DB file.


Briefly we will look at the initial configuration of the MySQL server to connect for it using by this module:

5. Productivity of the DBMS

Measurement of productivity of DB were carried out by the test "DB" of the module of system tests "SystemTests", by performing operations over the records of the structure: <name char (20), descr char (50), val double (10.2), id int (7), stat bool, reqKey string, reqVal string>.

Operation AMD Turion L625 1.6, 2G, FireBird [2.1.3 Local SuperServer; 100Base-TX; 2.5.2 100Base-TX SuperServer ForcedWrites=Off; ForcedWrites=On] Intel(R) Core(TM) i3 CPU 1.33GHz, 3G, HDD [2.5.2 100Base-TX SuperServer ForcedWrites=Off; ForcedWrites=On]
Creation of the 1000 records (sec.): 0.93; 1.15; 4.4; 5.2 3.68; 4.67
Updating of the 1000 records (sec.): 2.74; 2.94; 5.1; 5.2 3.88; 4.54
Getting of the 1000 records (sec.): 1.64; 2.22; 5.0; 27.8 3.69; 28.8
Seeking of the 1000 records (sec.): - 5.36; 32
Seeking in preload of the 1000 records (sec.): - 0.045; 0.065
Deleting of the 1000 record (sec.): 0.65; 1.04; 2.0; 2.4 1.69; 1.66

6. Notes

The DBMS FireBird has more architecture's limits and problems by the InterBase inheritance and from parent OS MS Windows which prevent it wide using for more tasks. Known limits and problems:

Links

Страницы, ссылающиеся на данную: HomePageEn/Doc
HomePageEn/Doc/OpenSCADA060
HomePageEn/Function


 
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