Describe column of table in the DBMS

Source: R/tbl_dbi.R

The get_column_info() retrieves the column information of the DBMS table through the tbl_bdi object of dplyr.

get_column_info(df)

Arguments

df

a tbl_dbi.

Value

An object of data.frame.

Column information of the DBMS table

  • SQLite DBMS connected RSQLite::SQLite():

    • name: column name

    • type: data type in R

  • MySQL/MariaDB DBMS connected RMySQL::MySQL():

    • name: column name

    • Sclass: data type in R

    • type: data type of column in the DBMS

    • length: data length in the DBMS

  • Oracle DBMS connected ROracle::dbConnect():

    • name: column name

    • Sclass: column type in R

    • type: data type of column in the DBMS

    • len: length of column(CHAR/VARCHAR/VARCHAR2 data type) in the DBMS

    • precision: precision of column(NUMBER data type) in the DBMS

    • scale: decimal places of column(NUMBER data type) in the DBMS

    • nullOK: nullability

Examples

library(dplyr)

if (requireNamespace("DBI", quietly = TRUE) & requireNamespace("RSQLite", quietly = TRUE)) {
  # connect DBMS
  con_sqlite <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")

  # copy heartfailure to the DBMS with a table named TB_HEARTFAILURE
  copy_to(con_sqlite, heartfailure, name = "TB_HEARTFAILURE", overwrite = TRUE)

  con_sqlite %>% 
    tbl("TB_HEARTFAILURE") %>% 
    get_column_info() %>%
    print() 
  
  # Disconnect DBMS   
  DBI::dbDisconnect(con_sqlite)
} else {
  cat("If you want to use this feature, you need to install the 'DBI' and 'RSQLite' package.\n")
}
#>                 name      type
#> 1                age   integer
#> 2            anaemia character
#> 3         cpk_enzyme    double
#> 4           diabetes character
#> 5  ejection_fraction    double
#> 6    hblood_pressure character
#> 7          platelets    double
#> 8         creatinine    double
#> 9             sodium    double
#> 10               sex character
#> 11           smoking character
#> 12              time   integer
#> 13       death_event character