Database Basics

Question 1

How are queries executed in the REST API?

Answer 1

The “Query” parameter, with a query string

Question 2

How are queries executed in the SOAP API?

Answer 2

using the query() method

Question 3

SOQL is used when you know which objects the data resides in and you want to:

Answer 3

Retrieve data from a single object or multiple objects that are related.
Count the number of records that meet a specified criteria.
Sort results as part of the query.
Retrieve data from number, date, or checkbox fields.

Question 4

What is a SOQL semi-join?

Answer 4

a subquery on another object in an IN clause to restrict the records returned

Question 5

What is a SOQL anti-join?

Answer 5

A subquery on another object in a NOT IN clause to restrict the records returned.

Question 6

Explain parent-to-child semi-join.

Answer 6

A parent to child semi-join is when a parent filters for specific child records in the where clause.

ex: selecting opportunities related to an account based on Stage.

select id, name from account where id in (select accountid from opportunity where stagename= ‘closed lost’)

Question 7

Explain parent-to-child anti-join.

Answer 7

A parent-to-child anti-join is when a parent filters for child records excluded from the where clause.

ex: selecting opportunities related to an account that don’t meet criteria.

select id, name from account where id not in (select accountid from opportunity where stagename = ‘closed lost’)

Question 8

Explain child-to-child semi-join.

Answer 8

A c2c semi-join is when a result set is filtered by a reference fields of two child objects.

ex: retrieving opportunities for contacts who have a source of ‘web’.

select id from opportunity where accountid in (select accountid from contact where leadsource=’Web’)

Question 9

Explain child-to-child anti-join.

Answer 9

A c2c semi-join is when a result set is filtered by the exclusion of reference fields of two child objects.

ex: retrieving opportunities for contacts who don’t have a source of ‘web’.

select id from opportunity where accountid not in (select accountid from contact where leadsource=’Web’)

Question 10

True or false:

Semi-joins & Anti joins can evaluate relationship queries in a SELECT clause.

Answer 10

True

Question 11

True/False:

Semi-joins/anti-joins can be combined in a single query.

Answer 11

True

Question 12

What are the 2 basic limits of semi & anti joins?

Answer 12

No more than two IN or NOT IN clauses.

You cannot use NOT with a semi or anti-join

Question 13

What are the restrictions of the main WHERE clause of a semi or anti join query?

Answer 13

The left operand must query a single ID (PK) or reference (FK).
The left operand can’t use relationships (ex: Account.id).

Question 14

True/false

A subquery must query a field referencing the same object type as the main query

Answer 14

true

Question 15

True/false

Standard SOQL limits apply to the number of records matched in a subquery .

Answer 15

False

Question 16

True/False.

A query that has a subquery is subject to the standard SOQL limits on the main query.

Answer 16

true

Question 17

True/False.

The selected column in a subquery must be a foreign key field.

Answer 17

true

Question 18

True/False.

The selected column in a subquery can traverse relationships.

Answer 18

false

Question 19

True/False.

You can query on the same object in a subquery as a main query.

Answer 19

false

Question 20

True/False.

You cannot nest a semi or anti join statement in another semi or anti join statement.

Answer 20

True

Question 21

True/False.

You can use semi/anti-joins in a subquery WHERE clase.

Answer 21

false

Question 22

True/False.

Subqueries can be used with the OR clause

Answer 22

false

Question 23

What four clauses are not supported in subqueries?

Answer 23

Count
For Update
Order By
Limit

Question 24

Which objects are not supported in subqueries?

Answer 24

ActivityHistory
Attachments
Event
EventAttendee
Note
OpenActivity
Tags (AccountTag, ContactTag, etc.)
Task

Question 25

In a child-to-parent relationship, what is the relationship name to the parent? Give an example

Answer 25

The foreign key. Contact.Account

Question 26

What property holds the reference to the parent object?

Answer 26

relationshipName

Question 27

For parent-to-child relationships, the parent object has a name for the child relationship that is unique to the parent...what is it? give an example.

Answer 27

the plural form of the child object. Account.Contacts

Question 28

What relationships can be queried using SOQL?

Answer 28

child-to-parent (n:1) Parent-to-child (1:n) parent-to-child as an FK in an aggregate query

Question 29

True/False: Any query, including subqueries, can include a WHERE clause, which applies to the object in the FROM clause in the current query.

Answer 29

True

Question 30

True/False: | Relationship queries can't be done on custom objects

Answer 30

false.

Question 31

Why is the plural form of the relationship required on creation of a custom relationship?

Answer 31

To reference the relationship in a relationship query

Question 32

In a child-to-parent relationship, how is the parent referenced?

Answer 32

using dot notation ex: parent__r.fieldname

Question 33

true/false: Parent-to-Child relationship queries use dot notation.

Answer 33

false.

Question 34

In Apex, how are parent to child relationship queries processed?

Answer 34

Perform query on parent object. Iterate over parent QueryResult with queryMore(). for each parent, retrieve the child QueryResult. Iterate over child recs using queryMore() on each QueryResult.

Question 35

In a parent-to-child query, explain the result set.

Answer 35

The query returns a set of Parent records, which contains a query result set of child fields from the subquery

Question 36

Give an example of a Parent-to-child relationship query

Answer 36

Select name, (select firstname, lastname from contacts) from account where name like 'Acme%'

Question 37

How does an outer join work in SOQL?

Answer 37

SOQL relationship queries return records even if the relevant foreign key field has a null value. ex: Select id, casenumber, account.id, account.name from case; if account.id is not populated for a record, it is returned with this query.

Question 38

Using the Enterprise WSDL, how can you determine if a parent-to-child relationship exists from the parent object?

Answer 38

In the WSDL, the parent object will contain an element with the plural name of the child relationship with a type of tns:QueryResult

Question 39

Using the Enterprise WSDL, how can you determine if a child-to-parent relationship exists from the child object?

Answer 39

In the WSDL, the child object will contain two elements: one representing the ID of the parent object, the other representing the parent object. ex: Account, type=ens: Account AccountId, type=tns:ID

Question 40

True/False: | All relationships are exposed in the API?

Answer 40

false

Question 41

What is the most reliable way to identify relationships?

Answer 41

execute a describeSObjects() call.

Question 42

How many child-to-parent relationships can be specified in a single query?

Answer 42

up to 35

Question 43

How many relationships can a custom object have?

Answer 43

25

Question 44

True/False: | All of the child-to-parent relationships can be referenced in a single query.

Answer 44

true

Question 45

How many parent-to-child relationships can be specified in a single query?

Answer 45

up to 20

Question 46

In a child-to-parent relationship, how many levels of relationships can be specified?

Answer 46

5

Question 47

How many levels are represented in the following relationship? Contact.Account.Owner.Firstname

Answer 47

3

Question 48

How many levels of relationship can a query specify in a parent-to-child relationship?

Answer 48

1 | ex: Account-to-opportunity, but not account to opportunity to OLI

Question 49

True/False: | You can filter on the body of a Note via relationship query.

Answer 49

False

Question 50

True/False: You can filter on the body of an Attachment via relationship query

Answer 50

false

Question 51

What field types cannot be filtered in a relationship query?

Answer 51

TextArea Blobs SControl objects

Question 52

What is the max number of rows that can be fetched in a subquery that involves an external object?

Answer 52

1000

Question 53

How many joins can a SOQL query have across external objects and other types of objects?

Answer 53

4

Question 54

Why does a join to an external object take longer?

Answer 54

Because each join requires a separate round trip to the external system.

Question 55

True/False: External objects support the ORDER BY clause in a relationship query, except when using OData 2.0 for SF Connect?

Answer 55

False

Question 56

True/false: If the main object of a query is an external object, then queryMore() only supports the main object and not the subqueries?

Answer 56

true

Question 57

What is the default batch size for a QueryResult Object? query() or queryMore()

Answer 57

500