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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).

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.

Any string that consists of characters: a-z, A-Z, 0-9, ., _, - can be used as a value.

Example of Variable Keys and Values

KeyValueIsKeyDescription
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