Document restriction on embedded objects #784
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docs/src/main/asciidoc/spanner.adoc
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| - embedded properties' column names must all be unique. | ||
| - embedded properties must be mutable; otherwise you'll get an error, such as `SpannerDataException: Column not found: parent`. | ||
| Therefore, you cannot use Kotlin's data class, which is immutable, to hold an embedded property. |
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This is not accurate. Kotlin's data class can have mutable field with 'var'. But the following definition (@Embedded var entityHistory) failed too with the same error message as #774 (comment):
@Table(name = "Requests")
data class Request(
@PrimaryKey val requestId: String,
val payload: String,
@Embedded var entityHistory: EntityHistory? = null
)
What's the better description?
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Can we rephrase somehow that the constructor should not contain embedded properties?
It seems that to use Kotlin data class with @Embedded, we can do something like:
@Table(name = "Requests")
data class Request(
@PrimaryKey val requestId: String,
val payload: String,
) {
@Embedded lateinit var entityHistory: EntityHistory
}or
@Table(name = "Requests")
data class Request(
@PrimaryKey val requestId: String,
val payload: String,
) {
@Embedded var entityHistory: EntityHistory? = null
}
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How about "Embedded properties must not be passed through constructor"? This would apply to both Java and Kotlin.
docs/src/main/asciidoc/spanner.adoc
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| - embedded properties' column names must all be unique. | ||
| - embedded properties must be mutable; otherwise you'll get an error, such as `SpannerDataException: Column not found: parent`. | ||
| Therefore, you cannot use Kotlin's data class, which is immutable, to hold an embedded property. |
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changed the title
Co-authored-by: Elena Felder <41136058+elefeint@users.noreply.github.com>
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Kudos, SonarCloud Quality Gate passed!
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* restriction on embedded objects * Enhanced restriction on embedded properties * Update docs/src/main/asciidoc/spanner.adoc Co-authored-by: Elena Felder <41136058+elefeint@users.noreply.github.com> Co-authored-by: Elena Felder <41136058+elefeint@users.noreply.github.com>
Related to #774