Powershell querying MongoDB

Question

1) Here's my schema:

{
    "_id" : ObjectId("53f4db1d968166157c2d57ce"),
    "init" : "SJ",
    "name" : "Steve Jobs",
    "companies" : [ 
        {
            "_id" : ObjectId("53f4db1d968166157c2d57cf"),
            "ticker" : "AAPL",
            "compname" : "Apple"
        }, 
        {
            "_id" : ObjectId("53f4db1d968166157c2d57d0"),
            "ticker" : "MSFT",
            "compname" : "Microsoft"
        }, 
        {
            "_id" : ObjectId("53f4db1d968166157c2d57d1"),
            "ticker" : "ABC",
            "compname" : "iTunes"
        }, 
        {
            "_id" : ObjectId("53f4db1d968166157c2d57d2"),
            "ticker" : "DEF",
            "compname" : "iPad Mini"
        }
    ]
}

I'm trying to get a list of compnames, using Powershell & MongoDB. Here's what I have so far:

$databaseName = "CompanyInfo"
$collectionName = "comps"
$client = New-Object -TypeName MongoDB.Driver.MongoClient -ArgumentList "mongodb://localhost:27017"
$server = $client.GetServer()
$database = $server.GetDatabase($databaseName)
$collection = $database.GetCollection($collectionName)

$query['init'] = "SJ"
$results = $collection.FindOne($query)
foreach ($result in $results) {
    write-host $result["companies.ticker"] /// Doesn't show me any records
}

This doesn't show me any records. How can I display companies.ticker info where init = "SJ"?

2) Btw, I get the following error after

$query['init'] = "SJ"

error

Cannot index into a null array.
At line:9 char:1
+ $query['init'] = "SJ"
+ ~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : NullArray

Any ideas as to why? I only have the MongoDB's standard index, which is on "_id", nothing else. My powershell script still works but I'm curious as to why I get that error.

[UPDATE Part 2] Thanks to @arco444, I no longer get error in part 2. Here's my revised code:

$query = @{'init' = "SJ"}
$collection.FindOne([MongoDB.Driver.QueryDocument]$query)

But I actually need help with part 1 - which is to display only the company tickers for a particular init. Any ideas on that one?

[ANSWER Part 1] Thanks again to @arco444 for directing me to the right path. After some tinkering around, I figured out what I missed. Here's my updated code:

$databaseName = "CompanyInfo"
$collectionName = "comps"
$client = New-Object -TypeName MongoDB.Driver.MongoClient -ArgumentList "mongodb://localhost:27017"
$server = $client.GetServer()
$database = $server.GetDatabase($databaseName)
$collection = $database.GetCollection($collectionName)

$query = new-object MongoDB.Driver.QueryDocument("init","SJ") /// Updated
$results = $collection.FindOne($query)
foreach ($result in $results["companies"]) { /// Updated
    write-host $result["ticker"] /// Updated
}

arco444 · Accepted Answer · 2014-08-27 16:27:10Z

1

From reading the MongoDB documentation, it looks like you need to initialise the query object properly first. Try this:

$query = new-object MongoDB.Driver.QueryDocument("init","SJ")
$results = $collection.FindOne($query)

edited Aug 27, 2014 at 16:27

answered Aug 27, 2014 at 15:06

arco444

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1 Comment

inquisitive_one Over a year ago

Thank you. That eliminated that error. But could you shed some light on how to display the company tickers using powershell?

inquisitive_one · Accepted Answer · 2014-08-27 17:04:34Z

0

Here's my updated code:

$databaseName = "CompanyInfo"
$collectionName = "comps"
$client = New-Object -TypeName MongoDB.Driver.MongoClient -ArgumentList "mongodb://localhost:27017"
$server = $client.GetServer()
$database = $server.GetDatabase($databaseName)
$collection = $database.GetCollection($collectionName)

$query = new-object MongoDB.Driver.QueryDocument("init","SJ") /// Updated
$results = $collection.FindOne($query)
foreach ($result in $results["companies"]) { /// Updated
    write-host $result["ticker"] /// Updated
}

answered Aug 27, 2014 at 17:04

inquisitive_one

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Comments

Thom Schumacher · Accepted Answer · 2015-06-09 15:15:11Z

So when I use your query procedure with

$mongoDbDriverPath = 'D:\mongo\driver\'
$mongoServer = 'myserver:27000'

Add-Type -Path "$($mongoDbDriverPath)MongoDB.Bson.dll"
Add-Type -Path "$($mongoDbDriverPath)MongoDB.Driver.dll"

$databaseName = 'Tickets'
$collectionName = 'MongoUserTicket'

$client = New-Object -TypeName MongoDB.Driver.MongoClient -ArgumentList "mongodb://$mongoServer"
$server = $client.GetServer()
$database = $server.GetDatabase($databaseName)
$collection = $database.GetCollection($collectionName)

$query = new-object Mongodb.driver.querydocument('Id','5')
$query2 = New-object Mongodb.driver.querydocument('Type','User')
$results = @()
foreach($item in $collection.Find($query))
{
    $results += $item
}

I get unexpected results for the query: When piping to Get member for results I get this:

   TypeName: MongoDB.Bson.BsonElement

Name        MemberType Definition                                                                                                                                    
----        ---------- ----------                                                                                                                                    
Clone       Method     MongoDB.Bson.BsonElement Clone()                                                                                                              
CompareTo   Method     int CompareTo(MongoDB.Bson.BsonElement other), int IComparable[BsonElement].CompareTo(MongoDB.Bson.BsonElement other)                         
DeepClone   Method     MongoDB.Bson.BsonElement DeepClone()                                                                                                          
Equals      Method     bool Equals(MongoDB.Bson.BsonElement rhs), bool Equals(System.Object obj), bool IEquatable[BsonElement].Equals(MongoDB.Bson.BsonElement other)
GetHashCode Method     int GetHashCode()                                                                                                                             
GetType     Method     type GetType()                                                                                                                                
ToString    Method     string ToString()                                                                                                                             
Name        Property   string Name {get;}                                                                                                                            
Value       Property   MongoDB.Bson.BsonValue Value {get;set;}

When entering $results on the shell prompt I get the data I expect:

$results 

Name                   Value                                                                                                                                                                                               
----                   -----                                                                                                                                                                                               
Id                 5
AccessToken            
CreatedOn              2013-09-27T22:05:52.246Z                                                                                                                                                                            
TokenExpiration  2013-09-27T22:20:52.246Z                                                                                                                                                                            
RefreshTokenExpiration 2013-09-28T22:05:52.246Z                                                                                                                                                                            
ProfileToken           BsonNull                                                                                                                                                                                            
Type              User                                                                                                                                                                                             
Id                 5
AccessToken            
CreatedOn              2013-09-27T23:42:28.492Z                                                                                                                                                                            
TokenExpiration  2013-09-27T23:57:28.492Z                                                                                                                                                                            
RefreshTokenExpiration 2013-09-28T22:06:04.071Z                                                                                                                                                                            
ProfileToken           BsonNull                                                                                                                                                                                            
Type              User

Thom Schumacher · Accepted Answer · 2015-06-11 04:05:54Z

here is what allowed me to get an object that i could operate on:

    $results = @()
foreach($item in $collection.Find($query))
{
    $props = @{}
    $item | foreach { $props[ $_.name ] = $_.value }
    $pso = [pscustomobject]$props
    $results += $pso
}

full code:

    $mongoDbDriverPath = 'D:\mongo\driver\'
$mongoServer = 'myserver:27000'

Add-Type -Path "$($mongoDbDriverPath)MongoDB.Bson.dll"
Add-Type -Path "$($mongoDbDriverPath)MongoDB.Driver.dll"

$databaseName = 'Tickets'
$collectionName = 'MongoUserTicket'

$client = New-Object -TypeName MongoDB.Driver.MongoClient -ArgumentList "mongodb://$mongoServer"
$server = $client.GetServer()
$database = $server.GetDatabase($databaseName)
$collection = $database.GetCollection($collectionName)

$query = new-object Mongodb.driver.querydocument('Id','5')
$query2 = New-object Mongodb.driver.querydocument('Type','User')
$results = @()
foreach($item in $collection.Find($query))
{
    $props = @{}
    $item | foreach { $props[ $_.name ] = $_.value }
    $pso = [pscustomobject]$props
    $results += $pso
}
$results

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