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DATAGRAPH-765 - Update docs with migration guide for dates.

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Luanne Misquitta
2015-11-03 13:07:34 +05:30
parent 2a2c3e1996
commit 5bcedea378
1 changed files with 23 additions and 7 deletions
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src/main/asciidoc/reference/migration/migration.adoc
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@@ -34,15 +34,31 @@ SDN 4 provides automatic type conversion for the obvious candidates: byte[] and
BigInteger types. In order to define bespoke type conversions for particular entity attribute, you can annotate a
field or method with `@Convert` to specify your own implementation of `org.neo4j.ogm.typeconversion.AttributeConverter`.
[NOTE]
====
The default Date converter is <<reference_programming-model_conversion-built_in,@DateString>>.
Use the `@DateLong` annotation when migrating from previous versions of SDN which represented Dates as Long.
====
You can find out more about type conversions here: <<reference_programming-model_conversion-custom,Custom Converters>>
== Date Format Changes
The default Date converter is <<reference_programming-model_conversion-built_in,@DateString>>.
SDN 3.x and earlier represented Dates as a String value consisting of the number of milliseconds since January 1, 1970, 00:00:00 GMT.
If you are upgrading to SDN 4.x from these versions and your application used the default, then you need to annotate your `Date`
properties with `@DateLong`.
Moreover, the property values in the graph need to be converted to numbers.
.Upgrade Date properties to numbers
[source,cypher]
----
MATCH (n:Foo) //All nodes which contain date properties to be migrated
WHERE NOT HAS(n.migrated)// Take the first 10k nodes that haven't been migrated yet
WITH n LIMIT 10000
SET n.dateProperty = toInt(n.dateProperty),n.migrated=1 //where dateProperty is the date with a String value to be migrated
RETURN count(n); //Run until the statement returns zero records
//Similar process to remove the migrated flag
----
However, if your application already represented Dates as `@GraphProperty(propertyType = Long.class)` then simply changing this to
`@DateLong` is sufficient.
== Obsolete Annotations
The following annotations are no longer used, either because they are no longer needed, or cannot be supported via Cypher.