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Comment: Published by Scroll Versions from space DEV and version r0681

D toc

Info

NOTE: The

D s item
itemdata types
rtrue
listed in this page reflect the raw data type of the converted column. Depending on the contents of the column, the Transformer Page may re-infer a different data type, when a dataset using this type of source is loaded.

Access/Read

When a Hive data type is imported, its JDBC data type is remapped according to the following table.

Tip

Tip: Data precision may be lost during conversion. You may want to generate min and max values and compute significant digits for values in your Hive tables and then compute the same in the

D s webapp
.

Source Data TypeSupported?
D s item
Data Type
Data Type
Notes
arrayYArray 
bigintYInteger
Info

NOTE: The

D s platform
may infer bigint columns containing very large or very small values as String data type.

binaryYString 
booleanYBool 
charYString 
dateYDatetime 
decimalYDecimal 
doubleYDecimal 
floatYDecimal
Info

NOTE: On import, some float columns may be interpreted as Integer data type in the

D s platform
. To fix, you can explicitly set the column's data type to Decimal in the Transformer page.

intYInteger 
mapYObject 
smallintYInteger 
stringYString 
structYObject 
timestampYDatetime 
tinyintYInteger 
uniontypeN  
varcharYString 

Notes: 

  • After a dataset has been imported using custom SQL from Hive, disabling type inference may not revert to the source data types for some columns. The workaround is to create a new imported dataset using the same custom SQL with type inference disabled before import. After the dataset is created, use it as a replacement for the corrupted instances of the previous Hive dataset.

Write/Publish

Create new table

Info

NOTE: By default, the maximum length of values published to VARCHAR columns is 256 characters. As needed, this limit can be changed for multiple publication targets. For more information, see Configure Application Limits.

D s item
itemData Type
Hive Data TypeNotes
Stringstring 
Integerbigint
Info

NOTE: The

D s platform
may infer Integer columns containing very large or very small values as String data type. Before you publish, you should verify that your columns containing extreme values are interpreted as Integer type. You can import a target schema to assist in lining up your columns with the expected target. For more information, see Overview of RapidTarget.

Decimaldouble 
Boolboolean 
DatetimeTimestamp/string (see Notes on Datetime columns below)Target data type is based on the underlying data. Time zone information is retained.
Objectstring 
Arraystring 

Append to existing table

If you are publishing to a pre-existing table, the following data type conversions apply:

  • Columns: 
    D s item
    itemdata types
  • Rows: Target table data types

In any table cell, a Y indicates that the append operation for that data type mapping is supported.

Info

NOTE: You cannot append to Hive map and array column types from

D s item
itemcolumns
of Map and Array type, even if you imported data from this source.

 StringIntegerDatetimeBoolDecimalMapArrayOut of Range error
CHARYYYYYYY 
VARCHARYYYYYYY 
STRINGYYYYYYY 
INT Y     NULL
BIGINT Y     n/a
TINYINT       NULL
SMALLINT       NULL
DECIMAL Y  Y  NULL
DOUBLE Y  Y  n/a
FLOAT    Y   NULL
TIMESTAMP  Y     
BOOLEAN   Y    

Notes on Datetime columns

Run Job

Columns in new tables created for output of Datetime columns are written with the Hive timestamp data type. These columns can be appended.

  • Before release 4.2.1, Datetime columns were written to Hive as type String. Jobs that were created in these releases and that write to pre-existing tables continue to behave this way.
  • A single job cannot write Datetime values to one table as String type and to another table as Timestamp type. This type of job should be split into multiple types. The table schemas may require modification.
    • The above issue may appear as the following error when executing the job:

      Code Block
      Unable to publish due to datetime data type conflict in column XXXX

Ad-Hoc Publishing

  • When you export pre-generated results to Hive, all new tables created for Datetime column values continue to store String data type in Hive for Release 4.2.1. These columns can be appended with new String data. 
  • When you publish results from a job through the Publishing dialog to Hive, all Datetime column values are written as String type.
  • If you are appending to a Timestamp column, the exported Datetime column must be in the following format: yyyy-MM-dd HH:mm:ss.xxxx