Replicate CouchDB Data from PowerShell

The CData ODBC Driver for CouchDB enables out-of-the-box integration with Microsoft's built-in support for ODBC. The ODBC driver instantly integrates connectivity to the real CouchDB data with PowerShell.

You can use the .NET Framework Provider for ODBC built into PowerShell to quickly automate integration tasks like replicating CouchDB data to other databases. This article shows how to replicate CouchDB data to SQL Server in 5 lines of code.

You can also write PowerShell code to execute create, read, update, and delete (CRUD) operations. See the examples below.

Create an ODBC Data Source for CouchDB

If you have not already, first specify connection properties in an ODBC DSN (data source name). This is the last step of the driver installation. You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs.

Set the following to connect:

• Url: The Url of your instance. For example: http://localhost:5984
• User The Apache CouchDB user account used to authenticate.
• Password The Apache CouchDB password associated with the authenticating user.

Connect to CouchDB

The code below shows how to use the DSN to initialize the connection to CouchDB data in PowerShell:

$conn = New-Object System.Data.Odbc.OdbcConnection
$conn.ConnectionString = "DSN=CData ApacheCouchDB Source x64"

Back Up CouchDB Data to SQL Server

After you enable caching, you can use the code below to replicate data to SQL Server.

Set the following connection properties to configure the caching database:

• CacheProvider: The name of the ADO.NET provider. This can be found in the Machine.config for your version of .NET. For example, to configure SQL Server, enter System.Data.SqlClient.

• CacheConnection: The connection string of properties required to connect to the database. Below is an example for SQL Server:

  Server=localhost;Database=RSB;User Id=sqltest;Password=sqltest;

The SQL query in the example can be used to refresh the entire cached table, including its schema. Any already existing cache is deleted.

$conn.Open()
# Create and execute the SQL Query
$SQL = "CACHE DROP EXISTING SELECT * FROM " + $Movies
$cmd = New-Object System.Data.Odbc.OdbcCommand($sql,$conn)
$count = $cmd.ExecuteNonQuery()
$conn.Close()

The driver gives you complete control over the caching functionality. See the help documentation for more caching commands and usage examples. See the help documentation for steps to replicate to other databases.

Other Operations

To retrieve CouchDB data in PowerShell, call the Fill method of the OdbcDataAdapter method. To execute data manipulation commands, initialize the OdbcCommand object and then call ExecuteNonQuery. Below are some more examples CRUD commands to CouchDB through the .NET Framework Provider for ODBC:

Retrieve CouchDB Data

$sql="SELECT MovieRuntime, MovieRating from Movies"
 
$da= New-Object System.Data.Odbc.OdbcDataAdapter($sql, $conn)
$dt= New-Object System.Data.DataTable
$da.Fill($dt) 
 
$dt.Rows | foreach {
 $dt.Columns | foreach ($col in dt{
 Write-Host $1[$_]
 }
}

Update CouchDB Data

$cmd = New-Object System.Data.Odbc.OdbcCommand("UPDATE Movies SET MovieRating='R' WHERE Id = @myId", $conn)
$cmd.Parameters.Add(new System.Data.Odbc.OdbcParameter("myId","001d000000YBRseAAH")
$cmd.ExecuteNonQuery()

Insert CouchDB Data

$cmd = New-Object System.Data.Odbc.OdbcCommand("INSERT INTO Movies SET MovieRating='R' WHERE Id = @myId", $conn)
$cmd.Parameters.Add(new System.Data.Odbc.OdbcParameter("myId","001d000000YBRseAAH")
$cmd.ExecuteNonQuery()

Delete CouchDB Data

$cmd = New-Object System.Data.Odbc.OdbcCommand("DELETE FROM Movies WHERE Id = @myid", $conn)
$cmd.Parameters.Add(new System.Data.Odbc.OdbcParameter("myId","001d000000YBRseAAH")
$cmd.ExecuteNonQuery()