Question

我正在尝试在具有匹配哈希数的文件之间创建差异计数。匹配的节点标签是QueryBlock和RegisterBlock。

我想建立这个QueryBlock和RegisterBlock节点的哈希总数以及匹配哈希的数量。然后从Total Register Hashes中减去匹配哈希的数量以得出差值

import java.util.*;
public class Menu
{
public static void main(String[] args){
    new Menu().use();
}
public void use() {
    int choice;
        while ((choice = readChoice()) != 0){
            switch (choice){
                case 1: ; break;                    
                case 2: ; break;
                case 3: ; break;
                case 4: ; break; 
            }
        }
}

private int readChoice(){
Scanner scanner = new Scanner(System.in);
    System.out.println("Main Menu:");
    System.out.println("1. Setting.");
    System.out.println("2. View hardware detail.");
    System.out.println("3. View Log.");
    System.out.println("4. Access Admin Mode.");
    System.out.println("0. Exit the system.");
    System.out.print("Enter a choice: ");
    return scanner.nextInt();
}
}

我正在运行此查询：

TotalRegisterHashes TotalQueryHashes  TotalMatchingHashes   Difference
1400                400               400                   1000

回复：

//Match QueryFiles to RegisterFiles using Block Hash Matches
MATCH (m:QueryBlock),(p:RegisterBlock)
WHERE m.qBlockHash = p.rBlockHash
RETURN 
    COUNT(p) AS TotalRegisterHashes, 
    COUNT(m) AS TotalQueryHashes,   
    COUNT(*) AS TotalMatchingHashes, 
    abs((COUNT(p) - COUNT(*))) AS Difference

TotalRegisterHashes TotalQueryHashes TotalMatchingHashes Difference 793 793 793 0是正确的，但其他人则没有。请你告诉我我哪里出错了。

Answer 1

运行count()函数时，在过滤完成后运行它们，所以在过滤之前无法为您提供节点的总数。你应该先计算总数。获取标签的所有节点的计数是优化的操作，使用预先计算的总数而不是实际必须计算db中的节点。获得给定标签的总计后，然后对查询的其余部分进行匹配哈希和差异。

//Match QueryFiles to RegisterFiles using Block Hash Matches
MATCH (m:QueryBlock)
WITH COUNT(m) AS TotalQueryHashes
MATCH (p:RegisterBlock)
WITH TotalQueryHashes, COUNT(p) AS TotalRegisterHashes
MATCH (m:QueryBlock),(p:RegisterBlock)
WHERE m.qBlockHash = p.rBlockHash
WITH TotalRegisterHashes, TotalQueryHashes, COUNT(*) AS TotalMatchingHashes
RETURN  TotalRegisterHashes, 
        TotalQueryHashes, 
        abs(TotalRegisterHashes - TotalMatchingHashes) AS Difference

如何为具有匹配属性的Neo4j节点创建差异分数？

1 个答案: