R 中的 Copy_to 导致日期被转换为数字列

Question

I am attempting to create a small, training database for a package that I am writing. I am using the following code to create the database:

library(tidyverse)
library(DBI)

dat <- data.frame(name = rep("Clyde", 100),
                  DOB = sample(x = seq(as.POSIXct('1970/01/01'), as.POSIXct('1995/01/01'), by="day"), 
                                       size = 100, replace = T))

# Example using schemas with SQLite
train_con <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")

## create tables in primary db
copy_to(dest = train_con, df = dat, name = "client_list", temporary = FALSE)

The above portion works fine. However, when I attempt to pull data from the database, I see that all dates have been converted to numeric.

train_con %>% tbl("client_list")

Can anybody tell me how to fix this? Thanks!

Answer 1

SQLite does not have a datetime type. In the absence of such a type POSIXct objects are sent to the database as seconds since the UNIX Epoch and SQLite does not know that they are intended to represent date times.

Either convert such columns yourself after you read them back into R or else use a different database. Nearly all databases except SQLite support this.