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https://issues.apache.org/jira/browse/DRILL-4420?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15476095#comment-15476095
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Holman Lan commented on DRILL-4420:
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Hello Laurent,
We have a few more question.
ODBC and JDBC support SQLGetTypeInfo and DatabaseMetaData.getTypeInfo()
respectively for reporting information about data types supported by the data
source. Would there be a method in the new Drill client API to retrieve such
information?
In contrib/native/client/src/clientlib/fieldmeta.cpp there is a static function
"static std::string getSQLType(common::MinorType type, common::DataMode mode)".
Is the returned string value meant to be the typename of the particular data
type, i.e. the typename can be used in CREATE TABLE statement or the CAST
function? Does ColumnMetadata::getDataType() return the same string as static
function getSQLType in fieldmeta.cpp for the same data type?
We would like to make sure we correctly map data types reported by Drill to SQL
type with the correct typename native to Drill. For example mapping MinorType
common::FLOAT8 to SQL_DOUBLE with typename bing "DOUBLE". The typename is
important to us as this is what the ODBC/JDBC application/user need to use in
the CREATE TABLE statement. In addition we would like to also make sure we
report the metadata consistently between SQLGetTypeInfo, SQLColumns, and result
set metadata for ODBC and DatabaseMetaData.getTypeInfo(),
DatabaseMetaData.getColumns() and ResultSetMetaData for JDBC.
Further to the question regarding signed and unsigned data types. The typename
is what the user/ODBC application/JDBC application would use in CREATE TABLE
statement. For example "CREATE TABLE tinyint_table(c1 TINYINT)". If the
typename is always TINYINT, how would the user specify in the CREATE TABLE
statement that a signed or unsigned TINYINT columns is to be created? Or is the
expectation that particular data source (e.g. Hive) only support either signed
or unsigned TINYINT but not both, and the sign-ness is implied depending on the
data source?
Thanks,
Holman
> C client and ODBC driver should move to using the new metadata methods
> provided by DRILL-4385
> ---------------------------------------------------------------------------------------------
>
> Key: DRILL-4420
> URL: https://issues.apache.org/jira/browse/DRILL-4420
> Project: Apache Drill
> Issue Type: Sub-task
> Reporter: Jacques Nadeau
>
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