This is a heads up regarding a breaking change that is currently in
avatica-go master and will be released as the next major version, 4.0.0.
In Apache Phoenix, string columns set to null or an empty string ("")
are considered to be equivalent. For more details on why this is the
case see [1].
While fixing a bug to correctly work with null values in avatica-go [2],
I had to break existing behavior.
Previous behavior: A string column set to null or an empty string will
be returned as an empty string.
New behavior: A string column set to null or an empty string will be
returned as a null.
The reason for this change is to take advantage of Go's database/sql
package's builtin NullString type [3]. This type allows userland code to
scan nullable columns into a variable without any errors.
Note: This breaking change will be part of 4.0.0 and will not affect
users using 3.x.x. However, to take advantage of database/sql's null
types, you will need to upgrade to 4.0.0 (when it is released) and
upgrade your import paths to github.com/apache/calcite-avatica-go/v4
This change is only applicable for Apache Phoenix and will not affect
HSQLDB.
[1] https://issues.apache.org/jira/browse/PHOENIX-947
[2] https://issues.apache.org/jira/browse/CALCITE-2763
[3] https://golang.org/pkg/database/sql/#NullString
