The tweaks are a way to control the behavior of certain tests. Currently, you need to search the DBItest source code to understand which tests are affected by which tweaks. This function is usually called to set the tweaks argument in a make_context() call.

tweaks(..., constructor_name = NULL, constructor_relax_args = FALSE,
  strict_identifier = FALSE, omit_blob_tests = FALSE,
  current_needs_parens = FALSE, union = function(x) paste(x, collapse =
  " UNION "), placeholder_pattern = NULL, logical_return = identity,
  date_cast = function(x) paste0("date('", x, "')"),
  time_cast = function(x) paste0("time('", x, "')"),
  timestamp_cast = function(x) paste0("timestamp('", x, "')"),
  blob_cast = identity, date_typed = TRUE, time_typed = TRUE,
  timestamp_typed = TRUE, temporary_tables = TRUE,
  list_temporary_tables = TRUE, is_null_check = function(x) paste0("(",
  x, " IS NULL)"))

Arguments

...

[any]
Unknown tweaks are accepted, with a warning. The ellipsis also makes sure that you only can pass named arguments.

constructor_name

[character(1)]
Name of the function that constructs the Driver object.

constructor_relax_args

[logical(1)]
If TRUE, allow a driver constructor with default values for all arguments; otherwise, require a constructor with empty argument list (default).

strict_identifier

[logical(1)]
Set to TRUE if the DBMS does not support arbitrarily-named identifiers even when quoting is used.

omit_blob_tests

[logical(1)]
Set to TRUE if the DBMS does not support a BLOB data type.

current_needs_parens

[logical(1)]
Set to TRUE if the SQL functions current_date, current_time, and current_timestamp require parentheses.

union

[function(character)]
Function that combines several subqueries into one so that the resulting query returns the concatenated results of the subqueries

placeholder_pattern

[character]
A pattern for placeholders used in dbBind(), e.g., "?", "$1", or ":name". See make_placeholder_fun() for details.

logical_return

[function(logical)]
A vectorized function that converts logical values to the data type returned by the DBI backend.

date_cast

[function(character)]
A vectorized function that creates an SQL expression for coercing a string to a date value.

time_cast

[function(character)]
A vectorized function that creates an SQL expression for coercing a string to a time value.

timestamp_cast

[function(character)]
A vectorized function that creates an SQL expression for coercing a string to a timestamp value.

blob_cast

[function(character)]
A vectorized function that creates an SQL expression for coercing a string to a blob value.

date_typed

[logical(1L)]
Set to FALSE if the DBMS doesn't support a dedicated type for dates.

time_typed

[logical(1L)]
Set to FALSE if the DBMS doesn't support a dedicated type for times.

timestamp_typed

[logical(1L)]
Set to FALSE if the DBMS doesn't support a dedicated type for timestamps.

temporary_tables

[logical(1L)]
Set to FALSE if the DBMS doesn't support temporary tables.

list_temporary_tables

[logical(1L)]
Set to FALSE if the DBMS doesn't support listing temporary tables.

is_null_check

[function(character)]
A vectorized function that creates an SQL expression for checking if a value is NULL.

Examples

# NOT RUN {
make_context(..., tweaks = tweaks(strict_identifier = TRUE))
# }