Hi @Lifeng Xu,
This is indeed how connections work, when you create a connection another one on the other direction is automatically created, if you delete it, the other one is deleted aswell.In your case, The first one will have an account in "connectedTo" field and a contact in "connectedFrom" field.The second one will have a contact in "connectedTo" field and an account in "connectedFrom" field.Same inversion in fields "ConnectedToRoleId" and "ConnectedFromRoleId"
If you do find all connections you will see both of them. Yet you can filter easily by checking only those that have an account in "ConnectedTo", or had a filter on "ConnectedToRoleId" field depending on your needs.Best regards,
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