Hibernate column order

Is it possible to use a JPA OrderColumn with Hibernate without making the order column nullable or giving it a default? I have an existing hibernate column order with a sequence column mapped in a long-standing Hibernate 3. I tried to reproduce the mapping in the equivalent JPA with Kotlin:. The mapping as a whole seems to work, hibernate column order, but Hibernate 5.

Summary: Required Optional Detail: Element. The persistence provider is responsible for maintaining the order upon retrieval and in the database. The persistence provider is responsible for updating the ordering upon flushing to the database to reflect any insertion, deletion, or reordering affecting the list. The OrderColumn annotation is specified on the side of the relationship that references the collection that is to be ordered. The order column is not visible as part of the state of the entity or embeddable class. The OrderBy annotation should be used for ordering that is visible as persistent state and maintained by the application. The OrderBy annotation is not used when OrderColumn is specified.

Hibernate column order

Developers often use the schemas as generated by Hibernate but currently we order columns in table DDL by name which can lead to inefficient physical layouts on a few DBs due to the need for padding. I propose we create a SPI for the ordering as well as a configuration parameter and by default order by coalesce staticOrder, Integer. I'd also like to add some kind of possibility to specify the order of columns through a static ordinal per column, if possible, but that would probably require a few changes to some annotations. Beta Was this translation helpful? Give feedback. I created the topic on discourse , I would love to participate, but I suspect this may be outside my skill level. My initial idea was a somewhat simple hack where you could set a property that toggles the following feature:. If possible would just retain the order in which the fields were defined in the java class. If this is not possible I suspect the JVM spec does not guarantee any ordering when traversing fields then add a simple ordering annotation that can be used with a comparator to sort the non-id columns prior to generation. I peeked around in the codebase and it looks doable without too much hassle, but I also understand that you need to keep the codebase clean without too many dirty hacks. The ColumnOrder annotation is actually an addition that allows fine grained control of the order. The main addition would be the SPI that allows automatic ordering based on some logic which a user configures just once.

I would strongly caution that whatever we do annotation-wise that there is a comparable solution for XML mappings.

Off the top of my head, ' order by s. There are those who, when presented with a glass that is exactly half full, say: this glass is half full. And then there are those who say: this glass is half empty. The world belongs, however, to those who can look at the glass and say: 'What's up with this glass? Excuse me? This is my glass?

Most of the time it does not matter. However, the order of columns in a DB might impact the physical storage of the data. Columns are ordered in the way they were added to the table. The smallint column will be padded to the same size as the bigint column due to a mechanism called alignment padding. This wastes both storage and performance since the additional bytes need to be read and written. Of course, the impact on smaller databases will be negligible. But in big databases, this might be a noticeable difference. If you now put the bigint column first you save 6 bytes per row. Keep in mind that after a table is created columns cannot be reordered. Hibernate v6.

Hibernate column order

Summary: Required Optional Detail: Element. The persistence provider is responsible for maintaining the order upon retrieval and in the database. The persistence provider is responsible for updating the ordering upon flushing to the database to reflect any insertion, deletion, or reordering affecting the list. The OrderColumn annotation is specified on the side of the relationship that references the collection that is to be ordered. The order column is not visible as part of the state of the entity or embeddable class. The OrderBy annotation should be used for ordering that is visible as persistent state and maintained by the application. The OrderBy annotation is not used when OrderColumn is specified.

U gg

I would strongly caution that whatever we do annotation-wise that there is a comparable solution for XML mappings. This is my glass? Element Detail name public abstract java. You signed in with another tab or window. Map; import org. The order column must be of integral type. Maintainer Author. If the auto-generated ecample uses the order column, you can debug that a d compare to your application to see where they differ. If you decide that you want to make the column order static via annotations, then that is what will be necessary, but I really doubt anyone would do that in general. Wdyt gavinking , djarnis73 and quaff? My personal aesthetic preference would be something like:. The world belongs, however, to those who can look at the glass and say: 'What's up with this glass? Hi Sebastien, I appologise for not listening the first time. I'll try to make this work that way, but I fear that we might still need some sort of canonical way to configure an explicit order for struct type.

.

If you are configuring your hibernate properties in Java code you can use the AvailableSettings. So the currently-proposed Instantiator annotation works like this:. I'm downloading 2. My initial idea was a somewhat simple hack where you could set a property that toggles the following feature: If possible would just retain the order in which the fields were defined in the java class. The world belongs, however, to those who can look at the glass and say: 'What's up with this glass? I'll try to make this work that way, but I fear that we might still need some sort of canonical way to configure an explicit order for struct type. Map; import org. Yeah, the PK stuff is a related concern, but I thought you had an idea on how to fix this through Index? AvailableSettings; import org. ColumnOrderingStrategyStandard is the new default used strategy from v6. So if we find an index that mentions all primary key columns and is unique, the we can treat that as definition for the primary key constraint.