如何使用VaultCustomQuery查询父状态的嵌套集合中的字段 [英] How to query on a field in nested collection of a parent state using VaultCustomQuery

问题描述

我有一个一对多的关系，我试图在我的状态下添加一个对象/类的列表。即
我有一个合同状态，其中包含附件列表 List< Attachment> ，其中 Attachment 是只是一类具有
attachmentHash ， uploadedDate ， fileType

I have a one-to-many relationship where I am trying to add a list of object/class in my state. i.e I have a contract state that has a list of attachments List<Attachment>, where Attachmentis just a class with fields like attachmentHash, uploadedDate, fileType

1. 我想查询子对象中的某些内容，但出现语法错误 AttachmentEntity不是PersistentState的子类型

QueryCriteria.VaultCustomQueryCriteria(
builder { (ContractSchemaV1.AttachmentEntity::uploadDate).equal(givenDate) })) 

我让AttachmentEntity是 PersistentState 的子类，节点启动时出现错误

I let AttachmentEntity be a subclass of PersistentState and the node started up with the error

org.hibernate.AnnotationException: net.corda.core.schemas.PersistentStateRef 
must not have @Id properties when used as an @EmbeddedId: project.schemas.ContractSchemaV1$AttachmentEntity.stateRef

似乎就像我做错了什么，在状态中表示数据类集合并将其转换为模式的最佳方法是什么？还是这已经是正确的方法，但是无法使用 VaultCustomQuery 查询嵌套集合？

Seems like I'm doing something wrong, whats the best way to represent a collection of data classes in the state and translate that in a schema? Or is this already the correct way, but there's no way to query the nested collection using VaultCustomQuery?

示例下面的实体。

object ContractSchema

 object ContractSchemaV1 : MappedSchema(schemaFamily = ContractSchema.javaClass, version = 1,
    mappedTypes = listOf(ContractEntity::class.java, AttachmentEntity:class.java)) {
@Entity
@Table(name = "contracts")
class ContractEntity(

        @Column(name = "issued_date")
        var issuedDate: Instant,

        @Column(name = "linear_id")
        var linearId: String,

        @OneToMany(fetch = FetchType.LAZY, cascade = arrayOf(CascadeType.PERSIST))
        @JoinColumns(
                JoinColumn(name = "transaction_id", referencedColumnName = "transaction_id"),
                JoinColumn(name = "output_index", referencedColumnName = "output_index"))
        var attachments: MutableSet<AttachmentEntity> = emptyList(),

) : PersistentState()

@Entity
@Table(name = "attachments")
class AttachmentEntity (

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    var id: Long? = null,

    @Column(name = "attachment_hash", nullable = false)
    var attachmentHash: String? = null,

    @Column(name = "attachment_name", nullable = false)
    var attachmentName: String? = null,

    @Column(name = "upload_date", nullable = true)
    var uploadDate: Instant? = null)
}

推荐答案

您的架构定义是正确的（您可以在此处看到另一个示例：在LinearState状态下查询嵌套集合）。

Your schema definition is correct (and you can see another example here: Querying nested collections in LinearState states).

但是， VaultCustomQueryCriteria 不支持查询嵌套集合。您必须执行直接JDBC查询才能查询嵌套集合的属性。

However, querying nested collections is not supported by VaultCustomQueryCriteria. You have to do direct JDBC queries to query attributes of the nested collections.

以下是Corda中直接JDBC查询的示例：

Here is an example of a direct JDBC query in Corda:

@Test
fun `test calling an arbitrary JDBC native query`() {
    val nativeQuery = "SELECT v.transaction_id, v.output_index FROM vault_states v WHERE v.state_status = 0"

    database.transaction {
        val jdbcSession = services.jdbcSession()
        val prepStatement = jdbcSession.prepareStatement(nativeQuery)
        val rs = prepStatement.executeQuery()
        var count = 0
        while (rs.next()) {
            val stateRef = StateRef(SecureHash.parse(rs.getString(1)), rs.getInt(2))
            Assert.assertTrue(cashStates.map { it.ref }.contains(stateRef))
            count++
        }
        Assert.assertEquals(cashStates.count(), count)
    }
}

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