英文:
Unable to pass a second param in query
问题
以下是翻译好的部分：
以下查询可以正常工作。
interface MyRepository : Neo4jRepository<Character?, Long?> {
@Query("MATCH (c1:Character)-[:positive]->(c2:Character) WHERE c1.id = $id RETURN c2")
fun findRelations(relation: String, id: Long): List<Character>
}
但是我也想将关系作为参数传递。但是当我执行这个操作时，出现了错误。
interface MyRepository : Neo4jRepository<Character?, Long?> {
@Query("MATCH (c1:Character)-[:$relation]->(c2:Character) WHERE c1.id = $id RETURN c2")
fun findRelations(relation: String, id: Long): List<Character>
}
错误。
> org.springframework.dao.InvalidDataAccessResourceUsageException:
> 无效输入 '$': 预期 "%", "(", 或标识符 (第1行，第24列 (偏移量: 23))\n"MATCH
> (c1:Character)-[:$relation]->(c2:Character) WHERE c1.id = $id RETURN
> c2"\n ^; 错误代码
> 'Neo.ClientError.Statement.SyntaxError
所以我尝试使用建议的 %。但那也引发了错误。`\%` 引发编译错误，因此使用双 `\\`。
interface MyRepository : Neo4jRepository<Character?, Long?> {
@Query("MATCH (c1:Character)-[:\\%relation]->(c2:Character) WHERE c1.id = $id RETURN c2")
fun findRelations(relation: String, id: Long): List<Character>
}
错误。
> org.springframework.dao.InvalidDataAccessResourceUsageException:
> 无效输入 '\\': 预期 "%", "(", 或标识符 (第1行，第25列 (偏移量: 24))\n"MATCH
> (c1:Character)-[:\\%relation]->(c2:Character) WHERE c1.id = $id RETURN
> c2"\n ^; 错误代码
> 'Neo.ClientError.Statement.SyntaxError
我漏掉了什么，哪里出现了语法错误？
英文:
The following query works fine.
interface MyRepository : Neo4jRepository<Character?, Long?> {
@Query("MATCH (c1:Character)-[:positive]->(c2:Character) WHERE c1.id = $id RETURN c2")
fun findRelations(relation: String, id: Long): List<Character>
}
But I want to pass that relation as a param too.
But when I perform this I end up with errors.
interface MyRepository : Neo4jRepository<Character?, Long?> {
@Query("MATCH (c1:Character)-[:$relation]->(c2:Character) WHERE c1.id = $id RETURN c2")
fun findRelations(relation: String, id: Long): List<Character>
}
The error.
> org.springframework.dao.InvalidDataAccessResourceUsageException:
> Invalid input '$': expected "%", "(" or an identifier (line 1,
> column 24 (offset: 23))\n"MATCH
> (c1:Character)-[:$relation]->(c2:Character) WHERE c1.id = $id RETURN
> c2"\n ^; Error code
> 'Neo.ClientError.Statement.SyntaxError
So I tried with % as suggested. That throws error too. \% throws compilation error thus using double \\.
interface MyRepository : Neo4jRepository<Character?, Long?> {
@Query("MATCH (c1:Character)-[:\\%relation]->(c2:Character) WHERE c1.id = $id RETURN c2")
fun findRelations(relation: String, id: Long): List<Character>
}
The error.
> org.springframework.dao.InvalidDataAccessResourceUsageException:
> Invalid input '\': expected "%", "(" or an identifier (line 1,
> column 25 (offset: 24))\n"MATCH
> (c1:Character)-[:\%relation]->(c2:Character) WHERE c1.id = $id RETURN
> c2"\n ^; Error code
> 'Neo.ClientError.Statement.SyntaxError
What am I missing, what is the syntax error?
答案1
得分: 1
Cypher不支持路径模式中的动态关系类型。尽管如此，您仍然可以在Cypher查询中使用动态关系类型（尽管效率可能不高）。
这应该适用于您：
@Query("MATCH (c1:Character)-[r]->(c2:Character) WHERE TYPE(r) = $relation AND c1.id = $id RETURN c2")
英文:
Cypher does not support dynamic relationship types in a path pattern. Nevertheless, you still can use dynamic relationship types in a Cypher query (although it will not be efficient).
This should work work you:
@Query("MATCH (c1:Character)-[r]->(c2:Character) WHERE TYPE(r) = $relation AND c1.id = $id RETURN c2")
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