Write a local data frame or file to the database

Functions for writing data frames or delimiter-separated files to database tables.

Usage

# S4 method for SQLiteConnection,character,character
dbWriteTable(
  conn,
  name,
  value,
  ...,
  field.types = NULL,
  overwrite = FALSE,
  append = FALSE,
  header = TRUE,
  colClasses = NA,
  row.names = FALSE,
  nrows = 50,
  sep = ",",
  eol = "\n",
  skip = 0,
  temporary = FALSE
)

# S4 method for SQLiteConnection,character,data.frame
dbWriteTable(
  conn,
  name,
  value,
  ...,
  row.names = pkgconfig::get_config("RSQLite::row.names.table", FALSE),
  overwrite = FALSE,
  append = FALSE,
  field.types = NULL,
  temporary = FALSE
)

Arguments

conn: a SQLiteConnection object, produced by DBI::dbConnect()
name: a character string specifying a table name. SQLite table names are not case sensitive, e.g., table names ABC and abc are considered equal.
value: a data.frame (or coercible to data.frame) object or a file name (character). In the first case, the data.frame is written to a temporary file and then imported to SQLite; when value is a character, it is interpreted as a file name and its contents imported to SQLite.
...: Needed for compatibility with generic. Otherwise ignored.
field.types: character vector of named SQL field types where the names are the names of new table's columns. If missing, types inferred with DBI::dbDataType()).
overwrite: a logical specifying whether to overwrite an existing table or not. Its default is FALSE.
append: a logical specifying whether to append to an existing table in the DBMS. Its default is FALSE.
header: is a logical indicating whether the first data line (but see skip) has a header or not. If missing, it value is determined following read.table() convention, namely, it is set to TRUE if and only if the first row has one fewer field that the number of columns.
colClasses: Character vector of R type names, used to override defaults when imputing classes from on-disk file.
row.names: A logical specifying whether the row.names should be output to the output DBMS table; if TRUE, an extra field whose name will be whatever the R identifier "row.names" maps to the DBMS (see DBI::make.db.names()). If NA will add rows names if they are characters, otherwise will ignore.
nrows: Number of rows to read to determine types.
sep: The field separator, defaults to ','.
eol: The end-of-line delimiter, defaults to '\n'.
skip: number of lines to skip before reading the data. Defaults to 0.
temporary: a logical specifying whether the new table should be temporary. Its default is FALSE.

Details

In a primary key column qualified with AUTOINCREMENT, missing values will be assigned the next largest positive integer, while nonmissing elements/cells retain their value. If the autoincrement column exists in the data frame passed to the value argument, the NA elements are overwritten. Similarly, if the key column is not present in the data frame, all elements are automatically assigned a value.

Examples

con <- dbConnect(SQLite())
dbWriteTable(con, "mtcars", mtcars)
dbReadTable(con, "mtcars")
#>     mpg cyl  disp  hp drat    wt  qsec vs am gear carb
#> 1  21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4
#> 2  21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4
#> 3  22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1
#> 4  21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
#> 5  18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2
#> 6  18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1
#> 7  14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4
#> 8  24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2
#> 9  22.8   4 140.8  95 3.92 3.150 22.90  1  0    4    2
#> 10 19.2   6 167.6 123 3.92 3.440 18.30  1  0    4    4
#> 11 17.8   6 167.6 123 3.92 3.440 18.90  1  0    4    4
#> 12 16.4   8 275.8 180 3.07 4.070 17.40  0  0    3    3
#> 13 17.3   8 275.8 180 3.07 3.730 17.60  0  0    3    3
#> 14 15.2   8 275.8 180 3.07 3.780 18.00  0  0    3    3
#> 15 10.4   8 472.0 205 2.93 5.250 17.98  0  0    3    4
#> 16 10.4   8 460.0 215 3.00 5.424 17.82  0  0    3    4
#> 17 14.7   8 440.0 230 3.23 5.345 17.42  0  0    3    4
#> 18 32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
#> 19 30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
#> 20 33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
#> 21 21.5   4 120.1  97 3.70 2.465 20.01  1  0    3    1
#> 22 15.5   8 318.0 150 2.76 3.520 16.87  0  0    3    2
#> 23 15.2   8 304.0 150 3.15 3.435 17.30  0  0    3    2
#> 24 13.3   8 350.0 245 3.73 3.840 15.41  0  0    3    4
#> 25 19.2   8 400.0 175 3.08 3.845 17.05  0  0    3    2
#> 26 27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
#> 27 26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
#> 28 30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2
#> 29 15.8   8 351.0 264 4.22 3.170 14.50  0  1    5    4
#> 30 19.7   6 145.0 175 3.62 2.770 15.50  0  1    5    6
#> 31 15.0   8 301.0 335 3.54 3.570 14.60  0  1    5    8
#> 32 21.4   4 121.0 109 4.11 2.780 18.60  1  1    4    2

# A zero row data frame just creates a table definition.
dbWriteTable(con, "mtcars2", mtcars[0, ])
dbReadTable(con, "mtcars2")
#>  [1] mpg  cyl  disp hp   drat wt   qsec vs   am   gear carb
#> <0 rows> (or 0-length row.names)

dbDisconnect(con)

Usage

Arguments

Details

See also

Examples