如何在 SAP HANA Graph 中创建多个顶点

Question

我正在尝试在 SAP HANA 中创建 2 个（多个）顶点，例如 -

为顶点ITEM和DATASET

创建两个table

CREATE COLUMN TABLE "GREEK_MYTHOLOGY"."ITEM" (
"ITEM_ID" VARCHAR(100) PRIMARY KEY,
"ITEM_NAME" VARCHAR(100)
);

CREATE COLUMN TABLE "GREEK_MYTHOLOGY"."DATASET" (
"DATASET_ID" VARCHAR(100) PRIMARY KEY,
"DATASET_NAME" VARCHAR(100)
);

并创建边作为 REFERENCES

CREATE COLUMN TABLE "GREEK_MYTHOLOGY"."REFERENCES" (
"REF_ID" INT UNIQUE NOT NULL,
"SOURCE" VARCHAR(100) NOT NULL
REFERENCES "GREEK_MYTHOLOGY"."ITEM" ("ITEM_ID")
ON UPDATE CASCADE ON DELETE CASCADE,
"TARGET" VARCHAR(100) NOT NULL
REFERENCES "GREEK_MYTHOLOGY"."DATASET" ("DATASET_ID")
ON UPDATE CASCADE ON DELETE CASCADE,
"TYPE" VARCHAR(100)
);

现在我想连接两个顶点（ITEM 和 DATASET）和边 REFERENCES 喜欢下面

CREATE GRAPH WORKSPACE "GREEK_MYTHOLOGY"."GRAPH"
EDGE TABLE "GREEK_MYTHOLOGY"."DATASET"
SOURCE COLUMN "SOURCE" 
TARGET COLUMN "TARGET"
VERTEX TABLE "GREEK_MYTHOLOGY"."ITEM" KEY COLUMN "ITEM_ID"
VERTEX TABLE "GREEK_MYTHOLOGY"."DATASET"KEY COLUMN "DATASET_ID"
KEY COLUMN "REF_ID";

但是它在第

行抛出异常

顶点 TABLE "GREEK_MYTHOLOGY"."DATASET"关键列 "DATASET_ID"

sql syntax error: incorrect syntax near "VERTEX": line 6 col 1 (at pos 200)

是否可以在 SAP HANA 图形中创建多个顶点？如果是，那么正确的方法是什么。

Answer 1

这里有个误会。 CREATE TABLE 语句中的 REFERENCES 子句与你要表示的图结构无关。相反，它在两个表之间定义了一个外键约束。

CREATE GRAPH WORKSPACE命令只接受一个EDGE TABLE和一个VERTEX TABLE作为参数。不过，你也可以在这里传入 synonyms 或者 views

这样，您就可以像这样创建视图 "ALL_ITEMS"：

CREATE VIEW "GREEK_MYTHOLOGY"."ALL_ITEMS" as
  SELECT "ITEM_ID" as "ID", "ITEM_NAME" as "NAME"  FROM "GREEK_MYTHOLOGY"."ITEM"
  UNION 
  SELECT "DATASET_ID" as "ID", "DATASET_NAME" as "NAME" FROM "GREEK_MYTHOLOGY"."DATASET";

然后引用这个视图：

CREATE GRAPH WORKSPACE "GREEK_MYTHOLOGY"."GRAPH"
       EDGE TABLE "GREEK_MYTHOLOGY"."DATASET"
            SOURCE COLUMN "SOURCE" 
            TARGET COLUMN "TARGET"
       VERTEX TABLE "GREEK_MYTHOLOGY"."ALL_ITEMS"
            KEY COLUMN "NAME";

可以使用这种方法，但您现在必须确保 "NAME" 值在两个表中都是唯一的，而不是 NULL。

如何在 SAP HANA Graph 中创建多个顶点

How to create multiple vertex in SAP HANA Graph

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