SQLITE INSERT DUPLICATE TO UNIQUE CODE

I would assume SQLite also uses some kind of a sequence for PK Which hashid value do you use then?Īlso, Access uses something called 'AutoNumber' field as PK for a table, Oracle and SQL Server uses sequences to increment PK value in the tables.

Your 'pseudocode' logic may theoretically work if you always insert a record into the emailprops table related to the last record in email table, but is that always the case? You may have 100 records in email table, and you want to insert a record into emailprops table related to the 27th record in email table.

SQLITE INSERT DUPLICATE TO UNIQUE CODE

But how do you know which record in emailprops table relates to which record in email table before you insert the record into emailprops table? And which hashid value to use as the value for compid in emailprops table? I don't think you can have this logic in the definition of the tables, you need to have it in the code that deals with INSERT INTO emailprops statements. So in order to INSERT any record into emailprops table, you need to have a record in the email table. #> row Sepal.Length Sepal.Width Petal.Length Petal.Width SpeciesĬreated on by the reprex package (v0.3.Well, you have here Parent (email) - Child (emailprops) relationship between the 2 tables. Insert_and_ignore_duplicates(con, iris_new) # iris_new has rows 101-250, so 50 are duplicated #> SQL insert or ignore into final select * from stage #> Warning: Factors converted to character Insert_and_ignore_duplicates(con, iris) # iris has rows 100-150 #> SQL create unique index identity_check on final (row) #> Warning: Closing open result set, pending rows #> The following objects are masked from 'package:base': #> The following objects are masked from 'package:stats': Thanks wrapped up the key commands into a little function, insert_and_ignore_duplicates(): library(DBI) If (nrow(check)= nrow(iris)) print('all is well :)') # make sure by reading the final & comparing row count with original iris # try for the second time - this should have no effect 'insert or ignore into final select * from stage ') 'create unique index identity_check on final (row) ') on conflict do nothing these differ in detail but the principle is the sameĬon <- dbConnect(RSQLite::SQLite(), ':memory:')

the contents of the stage layer are flipped over to final via a SQL command the exact formulation will depend on your dialect - sqlite has insert or ignore, while other dialects may have insert.

one that will be final, in my case called final this should have a constraint - in my case via unique index called identity_check on field row in final table.

one that will accept your R object, in my case called stage this should have no constraints (it should accept everything as it comes) and should be wiped clean before regular processing.

In short, I'm looking for something like the following to add 100 new rows - and to ignore the first 50 with that are duplicates (because of the duplicate row ID): library(DBI)Īn option you may consider - though it may seem like an overkill in your use case - is to use the BI concept known as stage table. If you use the INSERT IGNORE statement, the rows with invalid data that cause the error are ignored and the rows with valid data are inserted into the tableīut, neither DBI::dbWriteTable() and DBI::dbAppendTable() (or any other function from the DBI package) appear to support it. It seems like there is a way to do this in SQLite using an INSERT IGNORE command/part of a query: However, my question is: Is there a way to only add to a table rows that are unique? Here - correctly - none of the rows were inserted, because all were duplicates. #> Error: UNIQUE constraint failed: iris.row The DISTINCT clause allows you to remove the duplicate rows in the result set.

The DISTINCT clause is an optional clause of the SELECT statement. If you manually create a table using DBI::dbSendQuery(), you can specify a primary key my understanding is that this makes it so that duplicate rows cannot be added (by adding as a constraint that there are no duplicated primary keys): library(DBI) Introduction to SQLite SELECT DISTINCT clause. One challenge I've encountered concerns inserting duplicate rows.Īs in the following reprex, it's easy to (advertently or not) add duplicate rows: library(DBI) I am interested in creating and populating a SQLite database via R.

Sqlite insert duplicate to unique