AMashenkov commented on a change in pull request #455:
URL: https://github.com/apache/ignite-3/pull/455#discussion_r760571449
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File path:
modules/api/src/main/java/org/apache/ignite/table/mapper/DefaultColumnMapper.java
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@@ -21,7 +21,7 @@
import org.jetbrains.annotations.NotNull;
/**
- * Simple mapper implementation that map a column to a class field.
+ * Mapper implementation which maps object fields to the columns by their
names.
Review comment:
For now, we allow only one-to-one mapping. (otherwise 'object <-> row'
translation looks ambiguous)
So, seems, we will need both methods to resolve: column->field and
field->column.
As columns must be written to a row in order, we need dummy-mapping for
missed columns (to write 'null' or 'column default'). Resolving 'column->field'
allow us to write columns in right order and write a row in one iteration.
On the client side, we may not know all the columns and their defaults. Do
we know and I'm wrong?
Resolving 'field->column' allow here to write all fields to a tuple (or
whatever client protocol sends to a server in MsgPack format).
However, I've no idea how to deal with orphan fields, when no column exists
that matches field name.
* should we pass them to a server and then bypass validation and ignore
orphans.
* disallow orphans and fails with SchemaMismatch exception.
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