Use this article as a reference while you set up child relational tables.

Guidelines

Use the following guide lines to help you during your child relational table set-up process.

• Use multiple Child Relational Table queries per email, as you can reuse the queries to employ the personalization fields more effectively.
• Try to keep the parent to child Contact Matching limited to a maximum of 20.

  When you build a relational table or database query with a parent and child relationship, the data that is mapped from parent to child should be low. This ensures that the query doesn't take a large amount of time to complete.

  It is recommended that you regularly purge a table that frequently writes entries. This ensures that the parent or child table is more manageable.

• Preview and Click to View can be intermittently slow.
• Queries with child relational table capabilities are blocked from being set as the program contact source.

These terms and rules apply to child relational tables.

Terms to know

Relational table (RT): A relational table associated to a database with no child relational table associations.

Parent relational table (PRT): A relational table associated to a database and a child relational table.

Child relational table (CRT): A relational table associated to a parent relational table.

Database queries: Queries built from the database level that can include criteria from all connected data sources (RT, PRT, CRT); use these queries as a contact source for the email channel only.

Table queries: Queries built from the PRT level that can include only relational table data (RT, PRT, CRT); use these queries for email personalization.

Child relational table rules

• Child can have multiple parents.
• Parent can have multiple children.
• Child can be associated both to a parent and directly to a database (but cannot have children).
• Child cannot be associated to another child.

Limitations

The following are not supported for child relational table data.

• New or classic dynamic content rules
• Asset library
• Landing pages
• Classic queries
• Scoring
• Transact organizations
• You cannot use Child Relational Table or Relational Table query criteria if the query is a contact source for Mobile App Messages or SMS.
• Program entry
• Child Relational Table (CRT) criteria cannot be used as part of the entrance query as a contact source for a Program, or any Mobile App Messages or SMS messages.
• Child Relational Tables (CRT) criteria can be used in decisions and in email content in Programs.

Note: A Child Relational Table cannot be used as part of programs contact source query for entry, but you can use a Relational Table.

Use child relational table data to create database queries

You can build a database query with child relational table data criteria from any child relational table associated with a parent table that is associated directly to the database.

1. You can create a database query in several areas. Do one of the following.
   1. Go to Queries and click Create.
   2. Go to View Data, click the Queries tab, then click Create Query.
   3. Go to View Data, click the name of the Database you wish to query, then click Create Query.
   4. Go to View Data, click the name of the Database you wish to query, then click the Queries tab and click Create Query.
2. From any of the above areas, do the following.
   1. Click Relational Table.
   2. Click Choose to launch a selection box listing relational tables and/or parent relational tables available to query.

      If you select a parent relational table, all child tables associated to that parent are available in this query.

   3. Click Done.

      The parent table and all child relational tables associated to this parent are listed when you click Select Table Field. Parent table names are always listed on top in bold, followed by parent table field names which are alphabetized and indented. All child tables are listed alphabetically below the parent table.

3. Build the database query and click Done to view a summary.
4. Choose an action (Save, Save and Calculate, etc) for your query and click the corresponding button.
   • The top row always displays relational table: Parent Table Name.
   • When a child table association exists, query criteria are displayed as Table Name / Field Name.
   • When no child table association exists, query criteria are displayed as Field Name.

Use child relational table data to create table queries

Table queries are created from the parent Relational Table Summary screen. Table queries can include only parent table criteria, only child table criteria, or both parent and child table criteria.

1. Go to View Data.
2. Select Relational Tables tab.
3. Click the name of the parent relational table.
4. From the parent Relational Table Summary screen, click Create Table Query to begin.
5. Click Select Table Field.
6. Build the table query.
7. Click Done under each query expression to display a summary of your table query before taking additional action.
8. Click Done and you are able to view a summary of your table query one more time before taking additional action.
9. Click Save and Calculate.
10. To view table queries, do the following.
    1. Go to the parent Relational Table Summary screen as shown in Step 1 and click the Queries tab.
    2. Click the query name to go to the Query Summary screen for that query.