DBI internals

Intermediate Importing Data in R

Filip Schouwenaars

Instructor, DataCamp

dbGetQuery()

dbGetQuery(con, "SELECT * FROM products 
                                   WHERE contract = 1")

  id          name contract
1  2     Call Plus        1
2  9 Biz Unlimited        1

res <- dbSendQuery(con, "SELECT * FROM products 
                                   WHERE contract = 1")

dbFetch(res)

  id          name contract
1  2     Call Plus        1
2  9 Biz Unlimited        1

dbClearResult(res)

TRUE

dbFetch() one by one

res <- dbSendQuery(con, "SELECT * FROM products 
                                   WHERE contract = 1")

while(!dbHasCompleted(res)) {
+   chunk <- dbFetch(res, n = 1)
+   print(chunk)
+ }

  id      name contract
1  2 Call Plus        1
  id          name contract
1  9 Biz Unlimited        1
id       name     contract
<0 rows> (or 0-length row.names)

dbClearResult(res)

TRUE

Disconnect

dbDisconnect(con)

TRUE

Let's practice!

Intermediate Importing Data in R