Specifies whether String columns are described as VARCHAR or LONGVARCHAR. This property affects resultSetMetaData() calls; it does not affect getTypeInfo() calls.
Valid Values
varchar | longvarchar
Behavior
If set to varchar, String columns are described as VARCHAR.
If set to longvarchar, String columns are described as LONGVARCHAR.
Notes
To obtain data from String columns with the getClob() method, the StringDescribeType connection property must be set to longvarchar. Otherwise, calling getClob() results in an "unsupported data conversion" exception.
StringDescribeType affects all columns reported as String, even columns that were originally cast as Varchar. This is important to note because the Spark Thrift server, when returning result metadata for Varchar columns, reports column type as (12) STRING and precision as 2147483647. For the latest information on Spark SQL support for Varchar, refer to the Apache JIRA SPARK-5918 issue Web page.
To obtain data from String columns with the getClob() method, the StringDescribeType connection property must be set to longvarchar. Otherwise, calling getClob() results in an "unsupported data conversion" exception.