python - Can SQLAlchemy handle unknown polymorphic identities? -


i have 2 parts of app: ingestion , display. ideally, both of these @ same version of code, alas, reality doesn't allow simultaneous deployments. also, it's useful work on data ingestion before rolling out corresponding frontend.

the problem have i'm using sqlalchemy's polymorphic identities, , when add new class on backend, frontend doesn't know it. here's specific example. have code:

class campaign(basedata):     __tablename__ = 'campaign'     __mapper_args__ = {         'polymorphic_identity': 'parent',         'polymorphic_on': description     }  class subcampaign(campaign):     __mapper_args__ = {         'polymorphic_identity': 'sub'     }

then, add new class:

class othercampaign(campaign):     __mapper_args__ = {         'polymorphic_identity': 'other'     }

when insert rows db description column set other, throw error:

no such polymorphic_identity 'other' defined

is there way work around this? i'd happy ignore rows.

based on discussion zzzeek in comments, ended changing query on read side request valid data. instead of:

rows =  session.query(campaign).all()

i'm doing

valid_descriptions = [m.polymorphic_identity m in                        campaign.__mapper__.polymorphic_iterator()] rows =  session.query(campaign)\                 .filter(campaign.description.in_(valid_descriptions))\                 .all()

Comments

Post a Comment

Popular posts from this blog

authentication - Mongodb revoke acccess to connect test database -

i have ec2 instance mongodb 3.2.0 installed. have user admin access. can connect user , perform operation remotely. 1 can connect database test remote if knows ip mongo 11.11.11.11. although not able make operations, want restrict access user credentials can connect server. first need create users , grant roles users, example: use admin db.createuser( { user: "myuseradmin", pwd: "abc123", roles: [ { role: "useradminanydatabase", db: "admin" } ] } ) then need start server --auth parameter mongod --auth more information here
Read more

r - Update two sets of radiobuttons reactively - shiny -

i have read ( how make choices in radiobuttons reactive in shiny? ) shows me how update radiobutton s in reactive way. however, when try , update 2 sets of buttons same data, 1 set renders. example: server: # create example data wafer <- rep(c(1:3), each=3) length <- c(1,1,2,1,1,1,3,5,1) width <- c(3,1,6,1,1,1,1,1,6) dd <- data.frame(wafer, length, width) shinyserver(function(input, output, session){ # create reactive dataframe store data values <- reactivevalues() values$df <- data.frame() # lengths , widths of wafer user input <- eventreactive(input$do, { subset(dd, wafer %in% input$wafer, select = length:width) }) # update reactive data frame lengths , widths have been selected user input observe({ if(!is.null(a())) { values$df <- rbind(isolate(values$df), a()) } }) output$wl <- renderdatatable({ a() }) # update radio buttons unique length , widths stored in values$df # ever "observe" put first in co...
Read more

ios - Realm over CoreData should I use NSFetchedResultController or a Dictionary? -

i'm working on app using core data , nsfetchedresultcontroller many reasons switch use realm. saw there "realm version" of nsfetchedresultcontroller on github wouldn't compatible current code using core data. the view controller displaying list of people same school, address book. list sublist of people studied in same city. so thinking make 1 unique request database retrieve list of people , filter locally list within 1 dictionary per school [string: anyobject] string section name within tableview , anyobject array of people. first solution, make nsfetchedresultcontroller each school predicate filtering location. delete actions etc.. handled delegates -> not compatible realm create dictionaries , update them each actions... -> works realm it's annoying code. any better solution? edit: i need clarify request: i'd write class inherit uitableviewcontroller. this class has list of people sorted in alphabetical order the tableview has ...
Read more