PowerShell Scripting to Replicate HarperDB Data to MySQL

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

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

Set the Server, User, and Password connection properties to connect to HarperDB. Set UseSSL to secure connections with TLS/SSL.

Collecting HarperDB Data

1. Install the module:

   Install-Module HarperDBCmdlets

2. Connect to HarperDB:

   $harperdb = Connect-HarperDB -Server $Server -User $User -Password $Password

3. Retrieve the data from a specific resource:

   $data = Select-HarperDB -Connection $harperdb -Table "Customers"

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

   $data = Invoke-HarperDB -Connection $harperdb -Query 'SELECT * FROM Customers WHERE Country = @Country' -Params @{'@Country'='US'}

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

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

Inserting HarperDB 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 HarperDB 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 HarperDB resource (Customers) and to exist in the database.

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

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

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

• If you wish to replicate the HarperDB 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-HarperDB 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')}