Promotic
WikipediaLinkedInYoutubeTwitterFacebook

Storage - page of object PmTrend

Description:
Configuration of trend group data saving to disk.
Configuration items:
The data are stored into the computer memory and on the disk. On the disk they are stored either in one file on the disk (cyclic file - after filling up the maximum size of this file, the oldest records are removed) or by the backup mode - the size (in time or in the number of rows or the variable size according to the specific requirements) of one backup file (the backup is represented by one file on the disk or by one table in the database - according to the configuration) and the number of these backup files is defined. The oldest backup is removed on reaching the number of backups and on the creation of a new backup. Note: It is possible to leave the size of the backup unlimited and to create new backups by calling the BackupCreate method as well.

For obtaining information about saving parameters see PmTrend.GetPersistInfo method.

The data archive location can be changed during application runtime by the methods Open and Close.

Use the data on the discEnables data save/read to/from the computer disc archive.
Load data from disk into memory at application startIf the Use the data on the disc option is enabled and a non-zero number of records is set in the memory, then the latest data are read on starting the application from the disk (if any have been stored) into the memory. Thus a certain amount of data is on the disk and in the memory in parallel. The information is entered in percentage according to the maximum number of records in the memory.
Delayed data writing to diskOn the fast period of storing on the disk (e.g. in the order of second units) it is possible to define storing into the memory buffer. Each calling the Run (RunTime) method stores a record into this buffer. Moreover each N-th (N is the value specified by the configurator) storage clears the buffer and it moves all records stored there to the disk. The value 1 (default) means that each calling the Run (RunTime) method is stored at the same time on the disk and the buffer is not used.
Open on application start (valid only in Read only (new records can't be written) mode)Using this setting you can decide whether the object is opened and connected to data archive at application launch, or stays disconnected, i.e. it would be impossible to write new data and object variables data requests will be returned with no data. If it is disconnected, than the object can be opened at any time using the Open method. The object can also be closed by script using the Close method.

Caution: if the PmTrend object needs to enable data read and write immediatelly after start from this object, this option must be enabled.

Storage typeStorage type to disk, see Trend storage technology comparison.
Database dBase backups - Saving the backups into the dBase files in selected folder. The backup is a table (*.dbf file) of the dBase database. The oldest backup (table) is deleted after the defined number of backups is saved.
Promotic binary file cyclic - The storage in the Promotic binary format - in one cyclic file on the disk. After filling up the file by the defined number of records, the oldest records are removed on writing new records.
Database MS SQL server cyclic - The storage in the MS SQL Server database table. After filling up the table the oldest records are removed on writing new records.
Database Oracle cyclic - The storage in the Oracle database table. After filling up the table the oldest records are removed on writing new records.
Database MySQL cyclic - The storage in the MySql database table. After filling up the table the oldest records are removed on writing new records.
Database FireBird cyclic - The storage in the FireBird database table. After filling up the table the oldest records are removed on writing new records.
Database Access cyclic - The storage in the Microsoft Access table. After filling up the table the oldest records are removed on writing new records. The format of the *.MDB file is Access 2000.

This storage type has a limitation: If there are multiple PmTrend objects used with this storage type in the application, then there can be 63 such objects in one application at the most.

Database MS SQL server backups (obsolete) - The storage in the backup mode into the MS SQL Server database. The backup is the table in the SQL server database. The oldest backup (table) is removed after filling up the defined number of backups (tables). See the MS SQL server and MS SQL Express description.
Database Access backups (obsolete) - The storage in the backup mode into the Microsoft Access database. The backup is the table in the database (or *.mdb file). The oldest backup (table) is removed after filling up the defined number of backups (tables). The format of the *.MDB file is Access 2000.

This storage type has a limitation: If there are multiple PmTrend objects used with this storage type in the application, then there can be 63 such objects in one application at the most.

© MICROSYS, spol. s r. o.Tavičská 845/21 703 00 Ostrava-Vítkovice