Question

我正在

＆＃34;预期名为paramEmail＆＃34;
的参数

当我在Neo4j浏览器中执行以下cypher查询时。

CREATE (user:Owner {
   email:{paramEmail},
   password:{paramPassword},
   name:{paramName},
   category:{paramCategory}})
RETURN properties(user),
{
   paramEmail: "555@ali.com",
   paramPassword: "5555555",
   paramName: "Tony",
   paramCategory: "Category"
}

根据我的所有检查，这是正确的语法....我在这里缺少什么......另外，有没有更好的方法来呈现参数？

params: {parama:a,paramb:b,paramc:c}

没有工作。好的...所以我做了一些挖掘，发现javascript中的语法实际上来自我修复的.run，但现在我从第二个.then或.catch（无效令牌）得到了同样的错误。很抱歉，如果我看起来很基本，但我是Neo4j的新手，特别是v3.0，会话块被证明有点麻烦。有人可以告诉我块的错误：

neo4jSession
        .run ("MATCH (user {email : {paramEmail}}) RETURN count(user)=1 as user_exists",{ paramEmail: newUser.email})

        .then (function(result) {
            console.log("Neo4j Session started");
            if ( result.records[0].get('user_exists') !== true ) 
              {
            neo4jSession
              .run("CREATE (user:Owner {email:{paramEmail}, password:{paramPassword}, name:{paramName}, category:{paramCategory}}) RETURN properties (user)",
                {params: {
                    paramEmail: newUser.email,
                    paramPassword: newUser.password,
                    paramName: newUser.name,
                    paramCategory: newUser.category
                    }})
 //            .run (CREATE (user:newUser.category {email: {newUser.email}, password: {newUser.password}, 
  //                name: {newUser.name}, mobilenumber: {newUser.mobilenumber}) ASSERT newUser.email is UNIQUE RETURN properties (user));

                console.log( result.records[0].get("email") + " " + result.records[0].get("name") );
                neo4jSession.close();
              }
            else   // (found)
             {
               //   email address already exist
                console.log("email address already exist");
                neo4jSession.close();
             }  //end o f else

             //catch any system errors
        .then (function(error)
            {
            neo4jSession.close();   
            console.log(error);
            });
          }) // end of .then

抱歉......我想我也应该向你们展示数据库设置......见下文：

var neo4j = require('neo4j-driver').v1;
var neo4jdb = neo4j.driver("bolt://localhost:7474", neo4j.auth.basic("neo4j", "neo4j"),
     {
          trust: "TRUST_ON_FIRST_USE",
          encrypted:true
     });

var neo4jSession =neo4jdb.session();

最后通过移动一些大括号来消除会话块中的语法错误＆＃34;}＆＃34;和parens＆＃34;）＆＃34; ....仍然不太了解它但我理解逻辑....所以代码编译但代码的那部分显然没有执行!! ..代码显然停在＆＃34; neo4jSession＆＃34;之前的那一行。紧跟在＆＃34; console.log之后（＆＃34; Neo4j会议即将开始＆＃34;）...我已经在下面包含了修改后的代码：

 console.log("Neo4j Session about to start")
//start neo4j session
     neo4jSession
        .run ("MATCH (user {email : {paramEmail}}) RETURN count(user)=1 as user_exists",{ paramEmail: newUser.email})
        .then (function(result) {
            console.log("Neo4j Session started")
            if ( result.records[0].get('user_exists') !== true ) 
              {
            neo4jSession
              .run("CREATE (user:Owner {email:{paramEmail}, password:{paramPassword}, name:{paramName},mobilenumber:{parammobileNumber}, category:{paramCategory}}) RETURN user",
                {params: {
                    paramEmail: newUser.email,
                    paramPassword: newUser.password,
                    paramName: newUser.name,
                    parammobileNumber: newUser.mobilenumber,
                    paramCategory: newUser.category
                    }})
              .then (function(result)
                      {
                         console.log(user.name);
                         neo4jSession.close();  

                     })
              .then (function(error)
                      {
                         neo4jSession.close();  
                         console.log(error);
                     })

 //            .run (CREATE (user:newUser.category {email: {newUser.email}, password: {newUser.password}, 
  //                name: {newUser.name}, mobilenumber: {newUser.mobilenumber}) ASSERT newUser.email is UNIQUE RETURN properties (user));

                console.log( result.records[0].get("email") + " " + result.records[0].get("name") );
                neo4jSession.close();
              }
            else   // (found)
             {
               //   email address already exist
                console.log("email address already exist");
                neo4jSession.close();
             }  //end o f else
            }) // end of .then
             //catch any system errors
        .then (function(error)
            {
            neo4jSession.close();   
            console.log(error);
            });

Answer 1

除非我最近发现一些我不知道的事情，否则Web界面不支持参数（尽管neo4j shell支持这些参数，并且以编程方式支持）。

Answer 2

但是cycli客户端中的neo4j-shell支持参数（您必须安装zip分发版）。

只是做

export paramEmail=my@email.com

然后运行您的查询所有shell变量将作为参数传入。您可以使用env列出它们。

Answer 3

首先澄清一下，通过这里使用的javascript neo4j-driver来初始化与neo4j数据库的连接的代码。

var neo4j = require('neo4j-driver').v1
var neo4j_driver = neo4j.driver("bolt://localhost",
                                 neo4j.auth.basic("neo4j", "neo4j"),
                                 {
                                    trust: "TRUST_ON_FIRST_USE",
                                    encrypted: true
                                 });

var neo4jSession = neo4j_driver.session();

应保存在数据库中的新用户对象：

var newUser = {
   email: "max@somewhere.org",
   password: "s3cr3t",
   name: "Max",
   mobilenumber: "555-12345",
   category: "someCategory"
}

查询如下所示

session.run(query, [pObject])
.then(resultCallback)
.catch(errorCallback);

其中query是一个字符串（密码查询），pObject是一个可选对象，其键与查询字符串中的名称相匹配，例如'MATCH (u {name: "Max") RETURN u'将使用参数query = 'MATCH (u {name: { pName }}) RETURN u'和pObject = { pName: "Max"}。

如果返回结果，则会调用resultCallback，错误为errorCallback。

函数resultCallback接受一个参数，进一步称为result。然后从第一条记录中获取字段为result.record[0].get('sthing')，其中sthing与查询RETURN sthing中的变量匹配。 e.g。

query = '... RETURN user, object.name, count(sth) as sth_count'
...
// in resultCallback
r = result.record[0]
// right
r.get('user');
r.get('user').name;
r.get('object.name');
r.get('sth_count')
// wrong
r.get('user.name');
r.get('count(sth)');
r.get('sth');

函数errorCallback接受一个参数，进一步称为error，其中包含已发生错误的描述。

在结果和错误回调函数中完成查询时，应调用

session.close()。

调整后的示例如下所示：

var neo4j = require('neo4j-driver').v1
var neo4j_driver = neo4j.driver("bolt://localhost",
                                 neo4j.auth.basic("neo4j", "neo4j"),
                                 {
                                    trust: "TRUST_ON_FIRST_USE",
                                    encrypted: true
                                 });

var neo4jSession = neo4j_driver.session();

var newUser = {
   email: "max@somewheref.org",
   password: "s3cr3t",
   name: "Max",
   mobilenumber: "555-12345",
   category: "someCategory"
}

//start neo4j session
console.log("Neo4j Session about to start");

neo4jSession.run(
      // query has to be a string 
      "MATCH (user {email : {paramEmail}}) RETURN count(user)=1 as user_exists",
      // parameter Object with keys match those in the query string
      { paramEmail: newUser.email }
   )
   // result callback for outer query
   .then(function(result) {
      console.log("Neo4j Session started");
      console.log(result);
      // parameter to get is the same string as one of the RETURNed variables.
      console.log(result.records[0].get('user_exists')); 

      if (result.records[0].get('user_exists') !== true) {
         neo4jSession.run(
               "CREATE (user:Owner {email:{paramEmail}, password:{paramPassword}, name:{paramName}, mobilenumber:{parammobileNumber}, category:{paramCategory}}) RETURN user", // query has to be a string 
               { // parameter Object with keys match those in the query string
                  paramEmail: newUser.email,
                  paramPassword: newUser.password,
                  paramName: newUser.name,
                  parammobileNumber: newUser.mobilenumber,
                  paramCategory: newUser.category
               }                                   
            )
            // result callback for inner query
            .then(function(result) { // for results use .then(...)
               // parameter to get is the same string as one of the RETURNed variables. 
               console.log("New user" + result.records[0].get("user")); 

               neo4jSession.close();
            })
            .catch(function(error) { //for errors use .catch(...)
               console.log("Inner query error");
               console.log(error);
               neo4jSession.close();
            })
      } else // (found)
      {
         // email address already exist
         console.log("email address already exist");
      } // end of else
      neo4jSession.close();
   }) // end of .then

   //catch any system errors of outer query
   .catch(function(error) {
      console.log("Outer query error");
      console.log(error);
      neo4jSession.close();
   });

P.S。：newUser对象可以直接用作查询参数对象，只需调整查询字符串中的变量名称以匹配newUser的键。您甚至可以传递newUser对象，并将键作为属性名称和值使用，如下所示：

query = "CREATE (user:Owner {params}) RETURN user";
pObject = {params: newUser};
session.run(query, pObject).then(...).catch(...);

为什么我在neo4j浏览器

3 个答案: