Oracle Property Graph 让关系型数据也能用图的方式查询。本文用一组转账数据，走一遍建表、建图、单跳与多跳查询的完整流程，并整理 ORA-40954: unknown label 的常见原因。

01 | 准备测试表与数据

建议在空白 schema 中执行。若对象已存在，先手工删除或更换名称。

CREATE TABLE money_accounts (
    account_id   NUMBER       CONSTRAINT money_accounts_pk PRIMARY KEY,
    account_name VARCHAR2(50) NOT NULL
);

CREATE TABLE money_transfers (
    transfer_id    NUMBER       CONSTRAINT money_transfers_pk PRIMARY KEY,
    from_account_id NUMBER      NOT NULL,
    to_account_id   NUMBER      NOT NULL,
    amount          NUMBER(12,2),
    transfer_time   TIMESTAMP,
    CONSTRAINT money_transfer_from_fk
        FOREIGN KEY (from_account_id)
        REFERENCES money_accounts(account_id),
    CONSTRAINT money_transfer_to_fk
        FOREIGN KEY (to_account_id)
        REFERENCES money_accounts(account_id)
);

插入 6 个账户：

INSERT INTO money_accounts VALUES (1, '账户A');
INSERT INTO money_accounts VALUES (2, '账户B');
INSERT INTO money_accounts VALUES (3, '账户C');
INSERT INTO money_accounts VALUES (4, '账户D');
INSERT INTO money_accounts VALUES (5, '账户E');
INSERT INTO money_accounts VALUES (6, '账户F');

构造一条连续转账链，并增加一条捷径：

graph LR A[A] --> B[B] B --> C[C] C --> D[D] D --> E[E] E --> F[F] %% 分支/快捷路径 B -->|快捷路径| E

INSERT INTO money_transfers
VALUES (101, 1, 2, 1000, TIMESTAMP '2026-09-01 09:00:00');
INSERT INTO money_transfers
VALUES (102, 2, 3, 900, TIMESTAMP '2026-09-01 10:00:00');
INSERT INTO money_transfers
VALUES (103, 3, 4, 800, TIMESTAMP '2026-09-01 11:00:00');
INSERT INTO money_transfers
VALUES (104, 4, 5, 700, TIMESTAMP '2026-09-01 12:00:00');
INSERT INTO money_transfers
VALUES (105, 5, 6, 600, TIMESTAMP '2026-09-01 13:00:00');
-- B 直接转到 E，形成另一条路径
INSERT INTO money_transfers
VALUES (106, 2, 5, 500, TIMESTAMP '2026-09-01 14:00:00');
COMMIT;

02 | 创建属性图

显式声明两个标签：ACCOUNT 是顶点标签，TRANSFER 是边标签。

CREATE PROPERTY GRAPH money_graph
  VERTEX TABLES (
    money_accounts
      KEY (account_id)
      LABEL account
      PROPERTIES (
        account_id,
        account_name
      )
  )
  EDGE TABLES (
    money_transfers
      KEY (transfer_id)
      SOURCE KEY (from_account_id)
        REFERENCES money_accounts (account_id)
      DESTINATION KEY (to_account_id)
        REFERENCES money_accounts (account_id)
      LABEL transfer
      PROPERTIES (
        transfer_id,
        amount,
        transfer_time
      )
  );

未加双引号的标识符会被 Oracle 规范化为大写，因此 LABEL account 可以通过 IS ACCOUNT 匹配。

03 | 单跳查询

SELECT *
FROM GRAPH_TABLE(
  money_graph
  MATCH (a IS ACCOUNT)-[t IS TRANSFER]->(b IS ACCOUNT)
  COLUMNS (
    a.account_id   AS source_account,
    a.account_name AS source_name,
    t.amount       AS amount,
    b.account_id   AS target_account,
    b.account_name AS target_name
  )
)
ORDER BY source_account, target_account;

它应返回 6 条直接转账关系。

04 | 1～5 跳查询

SELECT *
FROM GRAPH_TABLE(
  money_graph
  MATCH (a IS ACCOUNT)-[IS TRANSFER]->{1,5}(b IS ACCOUNT)
  COLUMNS (
    a.account_id   AS source_account,
    a.account_name AS source_name,
    b.account_id   AS target_account,
    b.account_name AS target_name
  )
)
WHERE source_account = 1
ORDER BY target_account;

从账户 A 出发，可以匹配到：

• A→B：1 跳
• A→B→C：2 跳
• A→B→C→D：3 跳
• A→B→C→D→E：4 跳
• A→B→C→D→E→F：5 跳
• A→B→E：另一条 2 跳路径
• A→B→E→F：另一条 3 跳路径

因此 E 和 F 可能出现多次，因为查询匹配的是“路径”，而不只是去重后的终点。如果只想看可达账户，可以在外层去重：

SELECT DISTINCT target_account, target_name
FROM GRAPH_TABLE(
  money_graph
  MATCH (a IS ACCOUNT)-[IS TRANSFER]->{1,5}(b IS ACCOUNT)
  COLUMNS (
    a.account_id   AS source_account,
    b.account_id   AS target_account,
    b.account_name AS target_name
  )
)
WHERE source_account = 1
ORDER BY target_account;

05 | ORA-40954 常见原因

① 把表名当成标签名

图定义是 LABEL account，正确匹配是 (a IS ACCOUNT)，而不是 (a IS MONEY_ACCOUNTS)。IS 后面填的是 Label，不是底层表名。

② 没有显式声明预期标签

如果图定义没有 LABEL account，却查询 (a IS ACCOUNT)，Oracle 就可能找不到该标签。建议在教学和生产 DDL 中显式声明 Label。

③ 双引号导致大小写敏感

若创建时写 LABEL "Account"，标签名就是大小写敏感的 Account，查询必须写 (a IS "Account")，(a IS ACCOUNT) 无法匹配。最佳实践是标签不使用双引号。

④ 标签存在，但元素类型用错

TRANSFER 只定义在边上，却写成 (a IS TRANSFER)；或 ACCOUNT 只定义在顶点上，却写成 -[e IS ACCOUNT]->，都会出现标签无法用于当前位置的问题。

快速定位是哪一个标签有问题

先单独测试顶点标签：

SELECT *
FROM GRAPH_TABLE(
  money_graph
  MATCH (a IS ACCOUNT)
  COLUMNS (a.account_id AS account_id)
);

再单独测试边标签：

SELECT *
FROM GRAPH_TABLE(
  money_graph
  MATCH (a)-[t IS TRANSFER]->(b)
  COLUMNS (t.transfer_id AS transfer_id)
);

第一个失败说明 ACCOUNT 标签有问题；第二个失败说明 TRANSFER 标签有问题。

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