checkDuplicateFunction: Check for duplicated entries before addition
In JamesCuster/CARTMod: Functions and Shiny Modules for CART

This function takes a character vector of fields to check in the database for a possible duplication before an addition occurs

checkDuplicateFunction(
  checkDuplicate,
  reactiveData,
  inputData,
  db,
  dbTable,
  session = shiny::getDefaultReactiveDomain()
)

`checkDuplicate`	character vector specifing which fields to check for possible duplication. Default value is null, and no fields are checked for duplicates
`reactiveData`	Reactive which stores all of the tables from the database as seperate `data.frames`
`inputData`	a `data.frame` containing columns `ids, labels, type, choicesTable, choicesValues, choicesLabels` which correspond to `ids` The field names in the database. These ids will also be used as the inputId for shiny inputs. `labels` These are character values which will be used as the label for shiny inputs and be displayed above the input in the UI. `type` The type of shiny input to be used. `choicesTable, choicesValues, choicesLabels` Only used if the desired input has predefined choices (`selectInput/selectizeInput)`. If neither of these inputs are used, then the values should be `NA`. If one of these inputs is used then: `choicesTable` Is the table in the database where the choices for the given input are. `choicesValues` Is the column in the table which stores the numeric identifier for the choice `choicesLabels` Is the column in the table which stores the character name for the choices
`db`	a `DBIConnection` object, as returned by `dbConnect`. In other words, the object the database connection is saved to.
`dbTable`	The database table the new data will be added to.
`session`	These parameters are handled by `callModule` and can be ignored.