Establishing a Connection

With the CData Cmdlets users can install a data module, set the connection properties, and start scripting. This section provides examples of using our AlloyDB Cmdlets with native PowerShell cmdlets, like the CSV import and export cmdlets.

Installing and Connecting

If you have PSGet, installing the cmdlets can be accomplished from the PowerShell Gallery with the following command. You can also obtain a setup from the CData site.

Install-Module AlloyDBCmdlets

The following line is then added to your profile, loading the cmdlets on the next session:

Import-Module AlloyDBCmdlets;

You can then use the Connect-AlloyDB cmdlet to create a connection object that can be passed to other cmdlets:

$conn = Connect-AlloyDB -User 'alloydb' -Password 'admin' -Server '127.0.0.1' -Port '5432' -Database 'alloydb'

Connecting to AlloyDB

The following connection properties are required in order to connect to AlloyDB.

Server: The host name or IP of the server hosting the AlloyDB database.
Port (optional): The port of the server hosting the AlloyDB database. This property is set to 5432 by default.
User: The user which will be used to authenticate with the AlloyDB server.
Password: The password which will be used to authenticate with the AlloyDB server.
Database (optional): The database to connect to when connecting to the AlloyDB Server. If this is not set, the user's default database will be used.

Authenticating to AlloyDB

Standard Authentication

Standard authentication (using the user/password combination supplied earlier) is the default form of authentication.

No further action is required to leverage Standard Authentication to connect.

pg_hba.conf Auth Schemes

There are additional methods of authentication supported by the cmdlet which must be enabled in the pg_hba.conf file on the AlloyDB server.

You may find instructions about authentication setup on the AlloyDB Server here.

MD5

You can authenticate using MD5 password verification by setting the auth-method in the pg_hba.conf file to md5.

SASL

The cmdlet can authenticate by verifying the password with SASL (particularly, SCRAM-SHA-256).

To use this authentication method, set the auth-method in the pg_hba.conf file to scram-sha-256.

Kerberos

The authentication with Kerberos is initiated by AlloyDB Server when the CData Cmdlets PowerShell Module for AlloyDB is trying to connect to it. Set up Kerberos on the AlloyDB Server to activate this authentication method. Once you have Kerberos authentication set up on the AlloyDB server, see Using Kerberos for details regarding how to authenticate with Kerberos by the cmdlet.

Retrieving Data

After you have created a connection, you can use the other cmdlets to perform operations that you would normally expect to be able to perform against a relational database. The Select-AlloyDB cmdlet provides a native PowerShell interface for retrieving data:

$results = Select-AlloyDB -Connection $conn -Table ""alloydb"."schema01".Orders" -Columns @("ShipName, ShipCity") -Where "ShipCountry='USA'"

The Invoke-AlloyDB cmdlet provides an SQL interface. This cmdlet can be used to execute an SQL query via the Query parameter.

Piping Cmdlet Output

The cmdlets return row objects to the pipeline one row at a time. The following line exports results to a CSV file:

Select-AlloyDB -Connection $conn -Table "alloydb"."schema01".Orders -Where "ShipCountry = 'USA'" | Select -Property * -ExcludeProperty Connection,Table,Columns | Export-Csv -Path c:\my"alloydb"."schema01".OrdersData.csv -NoTypeInformation

You will notice that we piped the results from Select-AlloyDB into a Select-Object cmdlet and excluded some properties before piping them into an Export-CSV cmdlet. We do this because the CData Cmdlets append Connection, Table, and Columns information onto each row object in the result set, and we do not necessarily want that information in our CSV file.

However, this makes it easy to pipe the output of one cmdlet to another. The following is an example of converting a result set to JSON:

 
PS C:\> $conn  = Connect-AlloyDB -User 'alloydb' -Password 'admin' -Server '127.0.0.1' -Port '5432' -Database 'alloydb'
PS C:\> $row = Select-AlloyDB -Connection $conn -Table ""alloydb"."schema01".Orders" -Columns (ShipName, ShipCity) -Where "ShipCountry = 'USA'" | select -first 1
PS C:\> $row | ConvertTo-Json
{
  "Connection":  {

  },
  "Table":  ""alloydb"."schema01".Orders",
  "Columns":  [

  ],
  "ShipName":  "MyShipName",
  "ShipCity":  "MyShipCity"
}

Deleting Data

The following line deletes any records that match the criteria:

Select-AlloyDB -Connection $conn -Table "alloydb"."schema01".Orders -Where "ShipCountry = 'USA'" | Remove-AlloyDB

Modifying Data

The cmdlets make data transformation easy as well as data cleansing. The following example loads data from a CSV file into AlloyDB, checking first whether a record already exists and needs to be updated instead of inserted.

Import-Csv -Path C:\My"alloydb"."schema01".OrdersUpdates.csv | %{
  $record = Select-AlloyDB -Connection $conn -Table "alloydb"."schema01".Orders -Where ("Id = `'"+$_.Id+"`'")
  if($record){
    Update-AlloyDB -Connection $conn -Table "alloydb"."schema01".Orders -Columns @("ShipName","ShipCity") -Values @($_.ShipName, $_.ShipCity) -Where "Id  = `'$_.Id`'"
  }else{
    Add-AlloyDB -Connection $conn -Table "alloydb"."schema01".Orders -Columns @("ShipName","ShipCity") -Values @($_.ShipName, $_.ShipCity)
  }
}

Cmdlets for AlloyDB