makeSQLDataFrame: Construct SQLDataFrame from file.
In Liubuntu/SQLDataFrame: Representation of database tables in DataFrame metaphor.

Description Usage Arguments Details Examples

Given a file name, makeSQLDataFrame will write the file contents into SQLite database, and open the database table as SQLDataFrame.

1 2	makeSQLDataFrame(filename, dbkey = character(), dbname = NULL, dbtable = NULL, overwrite = FALSE, sep = ",", index = TRUE, ...)

`filename`	A `data.frame` or `DataFrame` object, or a character string of the filepath to the text file that to be saved as SQL database table.
`dbkey`	A character vector of column name(s) that could uniquely identify each row of the filename. Must be provided in order to construct a SQLDataFrame.
`dbname`	A character string of the filepath of to-be-saved database file. If not provided, will use a `tempfile(fileext = ".db")`.
`dbtable`	A character string for the to be saved database table name. If not provided, will use the name of the input `data.frame` or `DataFrame` object, or the `basename(filename)` without extension if `filename` is a character string.
`overwrite`	Whether to overwrite the `dbtable` if already exists. Default is FALSE.
`sep`	a character string to separate the terms. Not ‘NA_character_’. Default is `,`.

The provided file must has one or more columns to unique identify each row (no duplicate rows allowed). The file must be rectangular without rownames. (if rownames are needed, save it as a column.)

mtc <- tibble::rownames_to_column(mtcars)

## data.frame input
obj <- makeSQLDataFrame(mtc, dbkey = "rowname")
obj

## character input
filename <- file.path(tempdir(), "mtc.csv")
write.csv(mtc, file= filename, row.names = FALSE)
obj <- makeSQLDataFrame(filename, dbkey = "rowname")
obj