The Soql.TypeOf Class

The Soql.TypeOf class is designed to facilitate the construction of TYPEOF clauses for polymorphic field queries in SOQL. This class allows developers to query polymorphic relationships and handle different object types within a single query.

This class implements the Soql.Selectable interface, making it compatible with the fluent builder pattern used throughout the SOQL framework.

---

Constructors

TypeOf(String relationshipName)

Creates a new TypeOf instance with a relationship name.

Parameters:

• relationshipName - The polymorphic field name to query

Example:

Soql.TypeOf typeOfClause = new Soql.TypeOf('What');

TypeOf(SObjectField field)

Creates a new TypeOf instance with an SObjectField.

Parameters:

• field - The polymorphic SObjectField to query

Example:

Soql.TypeOf typeOfClause = new Soql.TypeOf(Task.WhatId);

TypeOf(Soql.ParentField field)

Creates a new TypeOf instance with a parent field.

Parameters:

• field - The polymorphic parent field to query

Example:

Soql.ParentField whatField = new Soql.ParentField('What');
Soql.TypeOf typeOfClause = new Soql.TypeOf(whatField);

---

Methods

when

Adds a WHEN clause and returns a builder for specifying fields.

Signature:

• Soql.WhenClause when(SObjectType objectType)

Parameters:

• objectType - The SObjectType to match in the WHEN clause

Returns:

• A Soql.WhenClause builder for specifying the fields to select

Example:

Soql.TypeOf typeOfClause = new Soql.TypeOf(Task.WhatId)
    .when(Account.SObjectType)
        .thenSelect(Account.Name, Account.Phone);

elseSelect

Adds an ELSE clause with field names to select when no WHEN conditions match.

Signatures:

• Soql.TypeOf elseSelect(List<String> fieldNames)
• Soql.TypeOf elseSelect(String fieldName)
• Soql.TypeOf elseSelect(String field1, String field2)
• Soql.TypeOf elseSelect(String field1, String field2, String field3)
• Soql.TypeOf elseSelect(String field1, String field2, String field3, String field4)
• Soql.TypeOf elseSelect(String field1, String field2, String field3, String field4, String field5)

Parameters:

• fieldNames - List of field names to select in the ELSE clause
• fieldName - Single field name to select
• field1, field2, etc. - Individual field names (null values are filtered out)

Returns:

• This TypeOf instance for method chaining

Examples:

// Single field
typeOfClause.elseSelect('Name');

// Multiple fields
typeOfClause.elseSelect('Name', 'Id');

// List of fields
typeOfClause.elseSelect(new List<String>{'Name', 'CreatedDate'});

---

Usage Examples

Basic TYPEOF Query

Soql.TypeOf typeOfClause = new Soql.TypeOf(Task.WhatId)
    .when(Account.SObjectType)
        .thenSelect(Account.Name, Account.Phone)
    .when(Opportunity.SObjectType)
        .thenSelect(Opportunity.Name, Opportunity.StageName)
    .elseSelect('Name');

Soql soql = DatabaseLayer.Soql.newQuery(Task.SObjectType)
    .addSelect(typeOfClause)
    .toSoql();

Complex TYPEOF with Multiple WHEN Clauses

Soql.TypeOf typeOfClause = new Soql.TypeOf(Event.WhatId)
    .when(Account.SObjectType)
        .thenSelect(Account.Name, Account.Type, Account.Industry)
    .when(Contact.SObjectType)
        .thenSelect(Contact.FirstName, Contact.LastName, Contact.Email)
    .when(Lead.SObjectType)
        .thenSelect(Lead.Name, Lead.Company, Lead.Status)
    .elseSelect('Name', 'Id');

List<Event> events = DatabaseLayer.Soql.newQuery(Event.SObjectType)
    .addSelect(typeOfClause)
    .addSelect(Event.Subject, Event.StartDateTime)
    .query();

---

Related Classes

• Soql.WhenClause - Builder for WHEN clause construction
• Soql.Selectable - Interface implemented by this class
• Soql.Builder - Main query builder that uses TypeOf clauses
• Soql.ParentField - For polymorphic parent field references