PowerShell Scripting to Replicate Greenplum Data to MySQL

The CData Cmdlets for Greenplum offer live access to Greenplum data 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 Greenplum and the CData Cmdlets for MySQL in PowerShell to replicate Greenplum data to a MySQL database.

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

To connect to Greenplum, set the Server, Port (the default port is 5432), and Database connection properties and set the User and Password you wish to use to authenticate to the server. If the Database property is not specified, the default database for the authenticate user is used.

Collecting Greenplum Data

1. Install the module:

   Install-Module GreenplumCmdlets

2. Connect to Greenplum:

   $greenplum = Connect-Greenplum -User $User -Password $Password -Database $Database -Server $Server -Port $Port

3. Retrieve the data from a specific resource:

   $data = Select-Greenplum -Connection $greenplum -Table "Orders"

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

   $data = Invoke-Greenplum -Connection $greenplum -Query 'SELECT * FROM Orders WHERE ShipCountry = @ShipCountry' -Params @{'@ShipCountry'='USA'}

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

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

Inserting Greenplum Data 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 Greenplum data, 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 Greenplum resource (Orders) and to exist in the database.

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

You have now replicated your Greenplum data to a MySQL database. This gives you freedom to work with Greenplum data 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 Greenplum and MySQL in PowerShell, you can pipe command results to perform the replication in a single line:

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

• If you wish to replicate the Greenplum data 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-Greenplum 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')}