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ardiadminguide:lookup [2016/11/20 10:03]
optrix created 		ardiadminguide:lookup [2018/12/11 02:17] (current)
optrix
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 Lookups are very similar to [[enumeration|enumerations]] - they translate one value into something more human-readable. Lookups are very similar to [[enumeration|enumerations]] - they translate one value into something more human-readable.
  
-The major difference between the two is the //number// of different values they support. Enumerations are suited to smaller, simpler sets of values - for example, having less than 10 distinct ​values.+The major difference between the two is the //number// of different values they support. Enumerations are suited to smaller, simpler sets of values - for example, having less than 10 distinct ​types of output text.
  
 Lookups are different. When you define a lookup, you upload a **lookup table** containing the lookup value and the translation. This can have //​hundreds//​ or even //​thousands//​ of values. Lookups are different. When you define a lookup, you upload a **lookup table** containing the lookup value and the translation. This can have //​hundreds//​ or even //​thousands//​ of values.
  
-This makes them very useful for looking up fault-codes and statuses.+This makes them very useful for looking up fault-codes and statuses ​in systems that share a single, large lookup table to translate those codes into meaningful messages. 
 + 
 +===Table Format=== 
 + 
 +The lookup table should be in //​tab-delimited//​ or //​comma-separated//​ format, with the lookup value first and the displayed value second. The table should **not** include a header. 
 + 
 +|0|OK| 
 +|1|Starting| 
 +|2|Running| 
 +|3|Stopping| 
 +|4|Stopped| 
 +|10|No Air Pressure| 
 +|11|No Power| 
 +|12|Comms Lost| 
 + 
 +===Performance Warning=== 
 + 
 +//Technical Section// 
 + 
 +Why does ARDI have both an //​enumeration//​ and a //lookup// type? The simple answer is **efficiency**. 
 + 
 +When dealing with small numbers of options, it's quite easy to send the complete lookup table out to ARDI clients. When there are only a half-dozen options to choose from, the complete list is trivial to transmit. 
 + 
 +However, when the list is significantly larger, it's puts a lot of load on the client and the network. Lookup properties instead push some of this additional work off to the driver, rather than loading-down the server and the client.  
 + 
 +Please use enumerations where possible, as a large number of small lookup properties will cause additional server load that will negatively impact performance.