General HydroStatics
Ship Stability Software |
Command of the Week
(New or interesting aspects of GHS that you may not know about) |
DB
(Requires GHS version 17.00 or later) |
Starting with version 17.00, GHS features a data-base command.
For example, DB PutFixWt copies all your fixed weights (in the current GHS session) into the Data Base. Similarly DB GetFixWt retrieves fixed weights. To find out what fixed weights are currently stored for a particular ship: DELETE ALL WEIGHTS DB GetFixWt STATUS FIXED Weight items stored in the Data Base are kept permanently and do not have to be renewed between GHS sessions. The storage context is keyed to the Geometry file name. To prove it, try this: READ SV.GF ADD "STORES" 1.0, 20.0F, 0.1P, 5.5 DB PutFixWt CLEAR READ FV.GF ADD "STORES" 0.25, 1.0A, 0.0, 6.6 DB PutFixWt CLEAR READ FV.GF DB GetFixWt STATUS FIXED CLEAR READ SV.GF DB GetFixWt STATUS FIXED What are the advantages of using the Data Base to store fixed-weight items?
The first time you issue any DB command, the Data Base folder is created automatically. After that, a subfolder (same name as the Geometry File) is automatically created for each Geometry file where DB commands are used. DB PutFixWt can include a description parameter. For example, if you want to copy only weight items having descriptions beginning with "DECK A", the command is: DB PutFixWt "DECK A*" The effect of this is the same as using the ADD PREFIX command. For example, ADD PREFIX "DECK A" DB PutFixWt Similarly, DB GetFixWt can have a description parameter. Also it can have a second parameter to specify the fraction of the Maximum Weight (if maximum weight and optionally VCG range are included when defining the weight with the ADD command). For example, try this: ADD "CARGO" 0.0, 9.0A, 0.0, 12.0 /MAX:10 /VRANGE: 12.0 DB PutFixWt "CARGO" DB GetFixWt "CARGO", 0.5 STATUS FIXED For deleting fixed weights, DB DeleteFixWt is provided. If a parameter is given, it narrows the target. Finally, DB LockFixWt protects all or selected weights against being modified by PutFixWt. A way to unlock a weight item in the Data Base is by deleting it and putting it back. Light-ship weights are addressed by a parallel set of DB commands: DB PutLSWt copies into the Data Base the main WEIGHT plus any ADDed weights having descriptions beginning with "+" or "*+". The following commands work like the FixWt commands but deal with the light-ship associated ADDed weights that begin with "+" or "*+": DB GetLSWt DB DeleteLSWt DB LockLSWt To view the DB documentation, the command is DB Info or simply DB. |
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