Neo4j CSV文件加載帶有空單元格

Question

我正在將一個基本的CSV文件加載到Neo4j數據庫中，該數據庫具有兩列-“名稱”和“屬性”。 名稱列始終具有一個值，“屬性”列可以具有一個值或空格。 我希望將值與關系“ property1”關聯。

我正在使用此代碼：

LOAD CSV WITH HEADERS FROM 'file:///fileName.csv' AS line
MERGE (Test_Document:A {name: line.name})
WITH line, Test_Document 
FOREACH (x IN CASE WHEN line.property IS NULL THEN [] ELSE [1] END |
  MERGE (Properties:B {property1: line.property})
WITH Test_Document, Properties
FOREACH (y IN CASE WHEN Properties IS NULL THEN [] ELSE [1] END |
  MERGE (Test_Document)-[:property1]->(Properties))

我收到一條錯誤消息：

Unexpected end of input: expected whitespace, LOAD CSV, START, MATCH, UNWIND, MERGE, CREATE, SET, DELETE, REMOVE, FOREACH, WITH, CALL, RETURN or ')' (line 8, column 54 (offset: 423))
"  MERGE (Test_Document)-[:property1]->(Properties))"

任何幫助，將不勝感激。

Answer 1

您的查詢有兩個問題：

1. 缺少第5行上的結束括號
2. Properties不在第二個FOREACH范圍內，因為它是在上一個FOREACH聲明的（在FOREACH中聲明的別名僅在該FOREACH子句內范圍）

嘗試這個：

LOAD CSV WITH HEADERS FROM 'file:///fileName.csv' AS line
MERGE (Test_Document:A {name: line.name})
WITH line, Test_Document 
FOREACH (x IN CASE WHEN line.property IS NULL THEN [] ELSE [1] END |
  MERGE (Properties:B {property1: line.property})
  MERGE (Test_Document)-[:property1]->(Properties)
)

Answer 2

另一種方法是僅當不存在缺少值的情況時，才使用WHERE創建關系：

LOAD CSV WITH HEADERS FROM 'file:///fileName.csv' AS line
WITH line, line.name AS Name, line.property AS Property
MERGE (Test_Document:A {name: Name})
WITH Property
WHERE Property <> ""
MERGE (Properties:B {property1: Property})
MERGE (Test_Document)-[:property1]->(Properties)

僅當屬性字段不為null時，才創建鏈接和B節點。