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Data Identification
Every variable stored in Mervis DB is identified by set of keys and values. Combination of of keys and values marked with attribute “IsKey=true” defines unique identification of variable (equivalent to primary key known from SQL world).
Keys
Any string that consists of characters: a-z, A-Z, 0-9, ., _, - can be used as a key. The key must not start with underscore (“_”) character and must not be empty.
Values
Any string that consists of characters: a-z, A-Z, 0-9, ., _, - can be used as a value.
Example of Variable Keys and Values
| Key | Value | IsKey | Description |
|---|---|---|---|
| SoftPlcRtId | “MyRTNumber3025” | True | Unique identification of Mervis RT defined by user |
| GUID | 546 | True | Unique identification of Mervis RT variable generated by Mervis IDE |
| VariableName | “Outside Temperature” | False | Non-unique variable name defined by user in Mervis IDE |