spec_sql_read_table | R Documentation |
spec_sql_read_table
dbReadTable()
returns a data frame that contains the complete data
from the remote table, effectively the result of calling dbGetQuery()
with
SELECT * FROM <name>
.
An empty table is returned as a data frame with zero rows.
The presence of rownames depends on the row.names
argument,
see sqlColumnToRownames()
for details:
If FALSE
or NULL
, the returned data frame doesn't have row names.
If TRUE
, a column named "row_names" is converted to row names.
If NA
, a column named "row_names" is converted to row names if it exists,
otherwise no translation occurs.
If a string, this specifies the name of the column in the remote table that contains the row names.
The default is row.names = FALSE
.
If the database supports identifiers with special characters,
the columns in the returned data frame are converted to valid R
identifiers
if the check.names
argument is TRUE
,
If check.names = FALSE
, the returned table has non-syntactic column names without quotes.
An error is raised if the table does not exist.
An error is raised if row.names
is TRUE
and no "row_names" column exists,
An error is raised if row.names
is set to a string and no corresponding column exists.
An error is raised when calling this method for a closed
or invalid connection.
An error is raised
if name
cannot be processed with dbQuoteIdentifier()
or if this results in a non-scalar.
Unsupported values for row.names
and check.names
(non-scalars,
unsupported data types,
NA
for check.names
)
also raise an error.
The following arguments are not part of the dbReadTable()
generic
(to improve compatibility across backends)
but are part of the DBI specification:
row.names
(default: FALSE
)
check.names
They must be provided as named arguments. See the "Value" section for details on their usage.
The name
argument is processed as follows,
to support databases that allow non-syntactic names for their objects:
If an unquoted table name as string: dbReadTable()
will do the
quoting,
perhaps by calling dbQuoteIdentifier(conn, x = name)
If the result of a call to dbQuoteIdentifier()
: no more quoting is done
Other sql specifications:
spec_sql_append_table
,
spec_sql_create_table
,
spec_sql_exists_table
,
spec_sql_list_fields
,
spec_sql_list_objects
,
spec_sql_list_tables
,
spec_sql_quote_identifier
,
spec_sql_quote_literal
,
spec_sql_quote_string
,
spec_sql_remove_table
,
spec_sql_unquote_identifier
,
spec_sql_write_table
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