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add an example use of hibernate.type.preferred_instant_jdbc_type

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Gavin King 2024-11-15 19:54:17 +01:00
parent d784d6a808
commit d6e1c9b2a8
1 changed files with 21 additions and 3 deletions
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24
documentation/src/main/asciidoc/introduction/Mapping.adoc
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@ -828,7 +828,7 @@ Here we summarize the ones we've just seen in the second half of this chapter, a
| `@Collate` | Specify a collation for a column
|===
In addition, there are some configuration properties which have a _global_ affect on how basic types map to SQL column types:
In addition, there are link:{doc-javadoc-url}org/hibernate/cfg/MappingSettings.html[some configuration properties] which have a _global_ affect on how basic types map to SQL column types:
.Type mapping settings
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@ -841,9 +841,25 @@ In addition, there are some configuration properties which have a _global_ affec
| `hibernate.type.preferred_duration_jdbc_type` | Specify the default SQL column type for mapping `Duration`
| `hibernate.type.preferred_instant_jdbc_type` | Specify the default SQL column type for mapping `Instant`
| `hibernate.timezone.default_storage` | Specify the default strategy for storing time zone information
| `` |
|===
For example, if we wanted to store an `Instant` using `timestamp with time zone` (called `timestamp` on MySQL, and `datetimeoffset` on SQL Server) instead of `timestamp` (`datetime` on MySQL, `datetime2` on SQL Server), then we could annotated every field of type `Instant`:
[source,java]
----
@JdbcTypeCode(SqlTypes.TIMESTAMP_WITH_TIMEZONE)
Instant instant;
----
Alternatively, we could affect every field of type `Instant` with the property `hibernate.type.preferred_instant_jdbc_type`:
[source,java]
----
config.setProperty(MappingSettings.PREFERRED_INSTANT_JDBC_TYPE, SqlTypes.TIMESTAMP_WITH_TIMEZONE);
----
[TIP]
====
These are _global_ settings and thus quite clumsy.
@ -863,7 +879,7 @@ Thus, the attribute is a sort of "derived" value.
|===
| Annotation | Purpose
| `@Formula` | Map an attribute to a SQL formula
| link:{doc-javadoc-url}org/hibernate/annotations/Formula.html[`@Formula`] | Map an attribute to a SQL formula
| `@JoinFormula` | Map an association to a SQL formula
| `@DiscriminatorFormula` | Use a SQL formula as the discriminator in <<mapping-inheritance,single table inheritance>>.
|===
@ -887,6 +903,8 @@ class Order {
}
----
The formula is evaluated every time the entity is read from the database.
[[derived-identity]]
=== Derived Identity