# Creating an ID namespace target (rule-based method)
<a name="create-id-namespace-target-rule-based"></a>

This topic describes the process of creating an ID namespace target using the **rule-based** method. This method uses matching rules to translate first-party data from a source to a target during an ID mapping workflow.

**To create an ID namespace target (rule-based)**

1. Sign in to the AWS Management Console and open the AWS Entity Resolution console at [https://console.aws.amazon.com/entityresolution/](https://console.aws.amazon.com/entityresolution/).

1. In the left navigation pane, under **Data preparation**, choose **ID namespaces**.

1. On the **ID namespaces** page, in the upper right corner, choose **Create ID namespace**.

1. For **Details**, do the following:

   1. For **ID namespace name**, enter a unique name.

   1. (Optional) For **Description**, enter an optional description.

   1. For **ID namespace type**, choose **Target**.

1. For the **ID namespace method**, choose **Rule-based**.

1. For **Data input**, under **Matching workflow**, do the following.

   1. Choose the account that’s associated with the ID namespace: either **Your AWS account** or **Another AWS account**.

   1. Depending to the type of account, select the **Matching workflow name** or enter the **Matching workflow ARN**.

1. For **Rule parameters**, do the following.

   1. Specify the **Rule controls** by choosing one of the following options based on your goal.


<table>
<thead>
  <tr><th>Your goal</th><th>Recommended option</th></tr>
</thead>
<tbody>
  <tr><td>Allow rules from both the source and the target</td><td><b>No preference</b></td></tr>
  <tr><td>Choose whether a source, target, or both can provide rules in an ID mapping workflow</td><td><b>Limited rules</b></td></tr>
</tbody>
</table>


      **Rule controls** must be compatible between the source and the target to be used in an ID mapping workflow. For example, if a source ID namespace limits rules to the target but the target ID namespace limits rules to the source, this results in an error.

   1. For **Matching rules**, AWS Entity Resolution automatically adds the rules from the matching workflow. 

1. For **Comparison and matching parameters**, do the following.

   1. Specify the **Comparison type** by choosing one of the following options based on your goal.


<table>
<thead>
  <tr><th>Your goal</th><th>Recommended option</th></tr>
</thead>
<tbody>
  <tr><td>Allow any comparison type to be used when you create the ID mapping workflow.</td><td><b>No preference</b></td></tr>
  <tr><td>Find any combination of matches across data stored in multiple input fields, regardless of whether the data is in the same or different input field.</td><td><b>Multiple input fields</b></td></tr>
  <tr><td>Limit comparison within a single input field, when similar data stored across multiple input fields shouldn't be matched.</td><td><b>Single input field</b></td></tr>
</tbody>
</table>


   1. Specify the **Record matching type** by choosing one of the following options based on your goal.


<table>
<thead>
  <tr><th>Your goal</th><th>Recommended option</th></tr>
</thead>
<tbody>
  <tr><td>Allow any comparison type to be used when you create the ID mapping workflow.</td><td><b>No preference</b></td></tr>
  <tr><td>Limit the record matching type to store only one matching record in the source for each matched record in the target when you create the ID mapping workflow. </td><td><b>Limited record matching </b><br />and<br /><b>One source to one target</b></td></tr>
  <tr><td>Limit the record matching type to store all matching records in the source for each matched record in the target when you create the ID mapping workflow. </td><td><b>Limited record matching </b><br />and<br /><b>Many sources to one target</b></td></tr>
</tbody>
</table>

**Note**  
You must specify compatible limitations for the source and target ID namespaces. For example, if a source ID namespace limits rules to the target but the target ID namespace limits rules to the source, this results in an error.

1. Specify the **Service access permissions** by choosing an **Existing service role name** from the dropdown list.

1. (Optional) To enable **Tags** for the resource, choose **Add new tag**, and then enter the **Key** and **Value** pair.

1. Choose **Create ID namespace**.

The ID namespace target is created. After you create the ID namespaces (source and target) required for an ID mapping workflow, you're ready to [create an ID mapping workflow](create-id-mapping-workflow.md).