Public/Add-Neo4jConstraint.ps1

function Add-Neo4jConstraint {
    <#
    .SYNOPSIS
       Add constraints to Neo4j properties

    .DESCRIPTION
       Add constraints to Neo4j properties

    .EXAMPLE
        Add-Neo4jConstraint -Label Server -Property computername -Unique

        # Ensure the 'computername' property on nodes with the 'Server' label are unique

    .PARAMETER Label
        Label that contains properties to create constraints on

    .PARAMETER Relationship
        Relationship that contains properties to create constraints on

    .PARAMETER Property
        One or more properties to apply constraints on

    .PARAMETER Unique
        Add a unique constraint on specified properties

    .PARAMETER Exists
        Add an exists constraint on specified properties

        This requires Neo4j Enterprise

    .PARAMETER As
        Parse the Neo4j response as...
            Parsed: We attempt to parse the output into friendlier PowerShell objects
                     Please open an issue if you see unexpected output with this
            Raw: We don't touch the response ($Response)
            Results: We expand the 'results' property on the response ($Response.results)
            Row: We expand the 'row' property on the responses results ($Response.results.data.row)

        We default to the value specified by Set-PSNeo4jConfiguration (Initially, 'Parsed')

        See ConvertFrom-Neo4jResponse for implementation details

    .PARAMETER MetaProperties
        Merge zero or any combination of these corresponding meta properties in the results: 'id', 'type', 'deleted'

        We default to the value specified by Set-PSNeo4jConfiguration (Initially, 'type')

    .PARAMETER MergePrefix
        If any MetaProperties are specified, we add this prefix to avoid clobbering existing neo4j properties

        We default to the value specified by Set-PSNeo4jConfiguration (Initially, 'Neo4j')

    .PARAMETER BaseUri
        BaseUri to build REST endpoint Uris from

        We default to the value specified by Set-PSNeo4jConfiguration (Initially, 'http://127.0.0.1:7474')

    .PARAMETER Credential
        PSCredential to use for auth

        We default to the value specified by Set-PSNeo4jConfiguration (Initially, not specified)

    .FUNCTIONALITY
        Neo4j
    #>

    [cmdletbinding(DefaultParameterSetName = 'Node')]
    param(
        [parameter(ParameterSetName = 'Node')]
        [string]$Label, # Injection alert
        [parameter(ParameterSetName = 'Relationship')]
        [string]$Relationship, # Injection alert
        [string[]]$Property, # Injection alert
        
        [parameter(ParameterSetName = 'Node')]
        [switch]$Unique,
        [parameter(ParameterSetName = 'Node')]
        [switch]$Exists,

        [validateset('Raw', 'Results', 'Row', 'Parsed')]
        [string]$As = $PSNeo4jConfig.As,
        [validateset('id', 'type', 'deleted')]
        [string]$MetaProperties = $PSNeo4jConfig.MetaProperties,
        [string]$MergePrefix = $PSNeo4jConfig.MergePrefix,

        [string]$BaseUri = $PSNeo4jConfig.BaseUri,

        [ValidateNotNull()]
        [System.Management.Automation.PSCredential]
        [System.Management.Automation.Credential()]
        $Credential =  $PSNeo4jConfig.Credential  
    )
    $Query = [System.Collections.ArrayList]@()
    if($PSCmdlet.ParameterSetName -eq 'Node') {
        write-verbose 'NODE'
        if($Unique) {
            Foreach($Prop in $Property) {
                write-verbose $prop
                [void]$Query.add("CREATE CONSTRAINT ON (l:$Label) ASSERT l.$Prop IS UNIQUE")
            }            
        }
        If($Exists) {
            Foreach($Prop in $Property) {
                # Requires enterprise. Interesting
                write-verbose $prop
                [void]$Query.add("CREATE CONSTRAINT ON (l:$Label) ASSERT exists(l.$Prop)")
            }
        }
    }
    if($PSCmdlet.ParameterSetName -eq 'Relationship') {
        write-verboe 'relationship'
        Foreach($Prop in $Property) {
            # Requires enterprise. Interesting
            [void]$Query.add("CREATE CONSTRAINT ON ()-[l:$Relationship]-() ASSERT exists(l.$Prop)")
        }
    }
    # TOOO: http://neo4j.com/docs/developer-manual/current/cypher/schema/constraints/#constraints-drop-a-node-key

    Write-Verbose "Query: [$Query]"
    $Params = . Get-ParameterValues -Properties As, MetaProperties, MergePrefix, Credential, BaseUri
    Invoke-Neo4jQuery @Params -Query $Query
}