So, I see in the 8.1.27 release notes that there's now a convenient button to add the {this}
field into named SQL update query parameters. But what does {this}
evaluate to? I have no idea what it does and "this" is a pretty awful search keyword so I'm having trouble figuring it out online.
From my prior to ignition coding experiences, I intuitively interpret the word this
in the same way as self
, but in that context this
would be an object, and it simply doesn't make sense to use an object in a query, so...
good question!
The "Scalar Query Update" section on {this} page may help shed some light (section quoted below too). I'm assuming it is intended for a similar use case with the Named Query, but maybe not.
Scalar Query Update
You can bind a non dataset type property to a SQL query to allow a singular value to be returned from the database with a scalar query. Now instead of returning multiple rows and columns, the query returns a single value from the first row of the first column. These types of SQL Query bindings can also be used to update the database on input components like a Text Field. Essentially, we mimic the bidirectionality of Tag and property bindings by adding in an update query to run whenever a value gets entered into the property with the binding. In our update query, we use the special parameter {this} to denote the new value from the bound property. If {this} is a string, it needs single quotes around it.
That's exactly what it is. It only applies to the context of a Vision named query binding.
I rarely wander through the Vision side of the manual, so I had no idea there are bi-directional named queries on that side of the fence. Any plans to add that sort of functionality to Perspective? I know you can get the same effect with an onChange event script and two named queries (one in each direction), so I understand if it's not planned, but I was impressed with the simplicity for the developer on the Vision binding.
I'm not aware of any plans. From what I remember, there are some big caveats with the Vision approach that make it hard to extend, but I'll never say never
Modules can add new binding types, too, if I can try to nerd snipe Phil a second time today
Hah! Busy with other nerdy things.