PowerShell Scripting to Replicate JSON Services to MySQL

The CData Cmdlets for JSON offer live access to JSON services from within PowerShell. Using PowerShell scripts, you can easily automate regular tasks like data replication. This article will walk through using the CData Cmdlets for JSON and the CData Cmdlets for MySQL in PowerShell to replicate JSON services to a MySQL database.

After obtaining the needed connection properties, accessing JSON services in PowerShell and preparing for replication consists of four basic steps.

See the Getting Started chapter in the data provider documentation to authenticate to your data source: The data provider models JSON APIs as bidirectional database tables and JSON files as read-only views (local files, files stored on popular cloud services, and FTP servers). The major authentication schemes are supported, including HTTP Basic, Digest, NTLM, OAuth, and FTP. See the Getting Started chapter in the data provider documentation for authentication guides.

After setting the URI and providing any authentication values, set DataModel to more closely match the data representation to the structure of your data.

The DataModel property is the controlling property over how your data is represented into tables and toggles the following basic configurations.

• Document (default): Model a top-level, document view of your JSON data. The data provider returns nested elements as aggregates of data.
• FlattenedDocuments: Implicitly join nested documents and their parents into a single table.
• Relational: Return individual, related tables from hierarchical data. The tables contain a primary key and a foreign key that links to the parent document.

See the Modeling JSON Data chapter for more information on configuring the relational representation. You will also find the sample data used in the following examples. The data includes entries for people, the cars they own, and various maintenance services performed on those cars.

Collecting JSON Services

1. Install the module:

   Install-Module JSONCmdlets

2. Connect to JSON:

   $json = Connect-JSON -URI $URI -DataModel $DataModel

3. Retrieve the data from a specific resource:

   $data = Select-JSON -Connection $json -Table "people"

   You can also use the Invoke-JSON cmdlet to execute pure SQL-92 statements:

   $data = Invoke-JSON -Connection $json -Query 'SELECT * FROM people WHERE [ personal.name.last ] = @[ personal.name.last ]' -Params @{'@[ personal.name.last ]'='Roberts'}

4. Save a list of the column names from the returned data.

   $columns = ($data | Get-Member -MemberType NoteProperty | Select-Object -Property Name).Name

Inserting JSON Services into the MySQL Database

With the data and column names collected, you are ready to replicate the data into a MySQL database.

1. Install the module:

   Install-Module MySQLCmdlets

2. Connect to MySQL, using the server address and port of the MySQL server, valid user credentials, and a specific database with the table in which the data will be replicated:

   $mysql = Connect-MySQL -User $User -Password $Password -Database $Database -Server $Server -Port $Port

3. Loop through the JSON services, store the values, and use the Add-MySQL cmdlet to insert the data into the MySQL database, one row at a time. In this example, the table will need to have the same name as the JSON resource (people) and to exist in the database.

   $data | % { $row = $_ $values = @() $columns | % { $col = $_ $values += $row.$($col) } Add-MySQL -Connection $mysql -Table "people" -Columns $columns -Values $values }

You have now replicated your JSON services to a MySQL database. This gives you freedom to work with JSON services in the same way that you work with other MySQL tables, whether that is performing analytics, building reports, or other business functions.

Notes

• Once you have connected to JSON and MySQL in PowerShell, you can pipe command results to perform the replication in a single line:

  Select-JSON -Connection $json -Table "people" | % { $row = $_ $values = @() $columns | % { $col = $_ $values += $row.$($col) } Add-MySQL -Connection $mysql -Table "people" -Columns $columns -Values $values }

• If you wish to replicate the JSON services to another database using another PowerShell module, you will want to exclude the Columns, Connection, and Table columns from the data returned by the Select-JSON cmdlet since those columns are used to help pipe data from one CData cmdlet to another:

  $columns = ($data | Get-Member -MemberType NoteProperty | Select-Object -Property Name).Name | ? {$_ -NotIn @('Columns','Connection','Table')}