Creates and initializes an object of "ScriptTableOperator" class.
Description
The function constructs a ScriptTableOperator object, that can be used to
execute a user-installed script or any Linux command inside database on
Teradata Vantage.
Usage
Script(
script.command = NULL,
returns = NULL,
data = NULL,
data.hash.column = NULL,
data.partition.column = NULL,
data.order.column = NULL,
is.local.order = FALSE,
sort.ascending = TRUE,
nulls.first = TRUE,
delimiter = "\t",
auth = NULL,
charset = "LATIN",
quotechar = NULL
)
Arguments
script.command |
Required Argument.
Specifies the command/script to run.
Types: character
|
returns |
Required Argument.
Specifies the output column definition. It contains a named
list of key-value pairs where key contains the column name
and value contains the Teradata Vantage SQL data type.
Types: named list of characters
|
data |
Optional Argument.
Specifies the tbl_teradata containing the input for the script.
Default Value: NULL
Types: tbl_teradata
|
data.hash.column |
Optional Argument.
Specifies the input tbl_teradata column to be used
for hashing.
The rows in the data are redistributed to AMPs based
on the hash value of the column specified. The
user-installed script file then runs once on each
AMP.
Note:
Default Value: NULL
Types: character
|
data.partition.column |
Optional Argument.
Specifies Partition By columns for "data".
Values to this argument can be provided as a
vector, if multiple columns are used for
partition.
Note:
This argument cannot be specified along
with "data.hash.column" argument.
This argument cannot be specified when the
argument "is.local.order" is set to TRUE.
If this argument is not specified, then
the entire result set, delivered by the
function, constitutes a single group or
partition.
Permitted Values: "ANY" OR one or more columns
in "data" tbl_teradata.
Default Value: NULL
Types: character OR vector of characters
|
data.order.column |
Optional Argument.
Specifies Order By columns for "data".
Values to this argument can be provided as a vector,
if multiple columns are used for ordering.
The column(s) mentioned in the argument is/are used
in ordering irrespective of whether the argument
"is.local.order" is set to TRUE or not.
Note:
Default Value: NULL
Types: character OR vector of characters
|
is.local.order |
Optional Argument.
Specifies whether the input data is to be ordered
locally or not. When set to TRUE, the data is ordered
locally.
Order by (Vs) Local Order by:
Order by: Specifies the order in which the values
in a group, or partition, are sorted.
Local Order by: Orders qualified rows on each AMP
in preparation to be input to a table function.
Note:
This argument is ignored if the argument
"data.order.column" is NOT specified or NULL.
When this argument is specified, the argument
"data.order.column" should be specified and the
column(s) specified in "data.order.column" is/are used
for local ordering.
Default Value: FALSE
Types: logical
|
sort.ascending |
Optional Argument.
Specfies whether to sort the result set in ascending or
descending order using columns specified in
"data.order.column" argument.
The sorting is ascending when this argument is set to
TRUE, descending otherwise.
Note:
Default Value: TRUE
Types: logical
|
nulls.first |
Optional Argument.
Specifies whether the result set containing NULL values
are to be listed first during ordering.
NULLs are listed first when this argument is set to TRUE,
otherwise NULLs are listed last.
Default Value: TRUE
Types: logical
|
delimiter |
Optional Argument.
Specifies the delimiter to use when reading the columns
from a row and writing result columns.
Note:
This argument cannot be same as "delimiter" argument.
This argument cannot be a NEWLINE character i.e., '\n'.
Default Value: "\t"
Types: character of length 1
|
auth |
Optional Argument.
Specifies an authorization to use when running the script which
binds an operating system user to the script via authorization
objects.
Use this argument to specify the fully qualified name of an
authorization object in single quotes.
If the database name is not provided, the name is fully qualified
using the current user or database.
The database user executing the script query must have the
following EXECUTE privileges:
EXECUTE privilege on the authorization object specified.
EXECUTE FUNCTION on td_sysfnlib.script.
Default Value: NULL
Types: character
|
charset |
Optional Argument.
Specifies the character encoding for all of the data passed to
and from the user-installed script.
Note:
Teradata recommends to use 'UTF-16', when using CHAR or
VARCHAR with CHARACTER SET UNICODE.
Permitted Values: "UTF-16", "LATIN"
Default Value: "LATIN"
Types: character
|
quotechar |
Optional Argument.
Specifies a character that forces all input and output of
the script to be quoted using this specified character.
Using this argument enables the Advanced SQL Engine to
distinguish between NULL fields and empty VARCHARs.
A VARCHAR with length zero is quoted, while NULL
fields are not.
If this character is found in the data, it will be escaped
by a second quote character.
Note:
This argument cannot be same as "delimiter" argument.
This argument cannot be a NEWLINE character i.e., '\n'.
Default Value: NULL
Types: character of length 1
|
Value
A named list of "ScriptTableOperator" class.
See Also
td_setup_sandbox_env, td_test_script,
td_cleanup_sandbox_env
Examples
# Replace "<schema_name>" with the name of the schema to search the file for.
schema_name <- "<schema_name>"
script_command <- gettextf("Rscript ./%s/mapper.R", schema_name)
# Get remote data source connection.
con <- td_get_context()$connection
# Load example data.
loadExampleData("script_example", "barrier")
# Create object(s) of class "tbl_teradata".
barrier <- tbl(con, "barrier")
# Create a ScriptTableOperator object that allows us to execute user script
# in Vantage.
script_obj <- Script(data = barrier %>% select(Name),
script.command = script_command,
returns = list("word"= "VARCHAR(15)",
"count_input"= "VARCHAR(2)")
)