ORM dont kill your DB, developers do

ORM Database

Developers

http://www.ﬂickr.com/photos/hoyvinmayvin/5103806609/ Guilherme Blanco
Thursday, March 1, 2012

ORMs donʼt kill your DB, developers do!

@guilhermeblanco

http://github.com/guilhermeblanco

InstaClick Inc.

Learning about good ORM
practices on @guilhermeblanco
talk at @confooca!


Agenda

http://www.ﬂickr.com/photos/emerzh/3072428824/

General Rule

RTFM

Dependency management

http://www.ﬂickr.com/photos/ollesvensson/3694625903/

Dependency Management


namespace AppBundleBlogBundleEntity;

/**
* @ORMEntity
*/
class Post
{
    /**
     * @ORMOneToMany(
     *   targetEntity="AppComment:Comment",
     *   mappedBy="post"
     * )
     */
    protected $comments;
}

namespace AppBundleCommentBundleEntity;

/**
* @ORMEntity
*/
class Comment
{
    /**
     * @ORMManyToOne(
     *   targetEntity="AppBlog:Post",
     *   inversedBy="comments"
     * )
*/
    protected $post;
}


namespace AppBundleBlogBundleEntity;

/**
* @ORMEntity
*/
class Post
{
    // ...
}

namespace AppBundleCommentBundleEntity;

/**
* @ORMEntity
*/
class Comment
{
    /**
     * @ORMManyToOne(targetEntity="AppBlog:Post")
     */
    protected $post;
}


Fetch Mode

http://www.ﬂickr.com/photos/comedynose/5318259802/

Fetch Mode

A fetching strategy is what ORM will use to retrieve
associated objects if the application needs to navigate
through them


Fetch Mode

Supported by all association types...


Fetch Mode

• OneToOne
• OneToMany
• ManyToOne
• ManyToMany


Fetch Mode

Available fetch modes...


Fetch Mode

• EAGER
• LAZY (default)
• EXTRA_LAZY


Fetch Mode

An association (collection or attribute), is
fetched immediately when owner is loaded

• EAGER
• LAZY (default)
• EXTRA_LAZY


Fetch Mode


• EAGER An association (collection or attribute),
• LAZY (default) is fetched when the application invokes
an operation over it
• EXTRA_LAZY


Fetch Mode


• EAGER An association (collection or attribute),
• LAZY (default) is fetched when the application invokes
an operation over it
• EXTRA_LAZY
Individual elements from association are
accessed from Database as needed. ORM
does not fetch the whole association
unless it is absolutely necessary

Fetch Mode
/**
* @ORMEntity
*/
class Post {
    /**
     * @ORMManyToOne(targetEntity="User", fetchMode="EAGER")
     */
    protected $author;

    /**
     * @ORMManyToMany(targetEntity="Tags", fetchMode="EXTRA_LAZY")
     * @ORMJoinTable(name="posts_tags")
     */
    protected $tagList;
}

/**
* @ORMEntity
*/
class Comment {
    /**
     * @ORMOneToMany(targetEntity="Post", fetchMode="LAZY")
     * @JoinColumn(name="post_id", referencedColumnName="id")
     */
    protected $post;
}


Fetch Mode
/**
* @ORMEntity
*/
Deadly sin
class Post {
    /**
     * @ORMManyToOne(targetEntity="User", fetchMode="EAGER")
     */
    protected $author;

    /**
     * @ORMManyToMany(targetEntity="Tags", fetchMode="EXTRA_LAZY")
     * @ORMJoinTable(name="posts_tags")
     */
    protected $tagList;
}

/**
* @ORMEntity
*/
class Comment {
    /**
     * @ORMOneToMany(targetEntity="Post", fetchMode="LAZY")
     * @JoinColumn(name="post_id", referencedColumnName="id")
     */
    protected $post;
}


Querying

http://www.ﬂickr.com/photos/pschadler/4932737690/

Querying

$query    = $entityManager->createQuery('
    SELECT p
      FROM Post p
');
$postList = $query->getResult();

foreach ($postList as $post) {
    $tagList = $post->getTagList();

    foreach ($tagList as $tag) {
        echo $tag->getName();
    }
}


Querying

    SELECT p
      FROM Post p
');

    $tagList = $post->getTagList(); N + 1 trolls?
    }
}


Querying

    SELECT p, t
      FROM Post p
      LEFT JOIN p.tagList t
');


    }
}


Querying

    SELECT p, t
      FROM Post p Pardon? DQL is
      LEFT JOIN p.tagList t
');
powerful! RTFM


    }
}


Querying

I know you all don’t trust me...


Querying

...but take a look at its EBNF grammar...


QueryLanguage ::= SelectStatement | UpdateStatement | DeleteStatement
SelectStatement ::= SelectClause FromClause [WhereClause] [GroupByClause] [HavingClause] [OrderByClause]
UpdateStatement ::= UpdateClause [WhereClause]
DeleteStatement ::= DeleteClause [WhereClause]
JoinAssociationPathExpression ::= IdentificationVariable "." (CollectionValuedAssociationField | SingleValuedAssociationField)
AssociationPathExpression ::= CollectionValuedPathExpression | SingleValuedAssociationPathExpression
SingleValuedPathExpression ::= StateFieldPathExpression | SingleValuedAssociationPathExpression
StateFieldPathExpression ::= IdentificationVariable "." StateField | SingleValuedAssociationPathExpression "." StateField
SingleValuedAssociationPathExpression ::= IdentificationVariable "." SingleValuedAssociationField
CollectionValuedPathExpression ::= IdentificationVariable "." {SingleValuedAssociationField "."}* CollectionValuedAssociationField
StateField ::= {EmbeddedClassStateField "."}* SimpleStateField
SimpleStateFieldPathExpression ::= IdentificationVariable "." StateField
SelectClause ::= "SELECT" ["DISTINCT"] SelectExpression {"," SelectExpression}*
SimpleSelectClause ::= "SELECT" ["DISTINCT"] SimpleSelectExpression
UpdateClause ::= "UPDATE" AbstractSchemaName ["AS"] AliasIdentificationVariable "SET" UpdateItem {"," UpdateItem}*
DeleteClause ::= "DELETE" ["FROM"] AbstractSchemaName ["AS"] AliasIdentificationVariable
FromClause ::= "FROM" IdentificationVariableDeclaration {"," IdentificationVariableDeclaration}*
SubselectFromClause ::= "FROM" SubselectIdentificationVariableDeclaration {"," SubselectIdentificationVariableDeclaration}*
WhereClause ::= "WHERE" ConditionalExpression
HavingClause ::= "HAVING" ConditionalExpression
GroupByClause ::= "GROUP" "BY" GroupByItem {"," GroupByItem}*
OrderByClause ::= "ORDER" "BY" OrderByItem {"," OrderByItem}*
Subselect ::= SimpleSelectClause SubselectFromClause [WhereClause] [GroupByClause] [HavingClause] [OrderByClause]
UpdateItem ::= IdentificationVariable "." (StateField | SingleValuedAssociationField) "=" NewValue
OrderByItem ::= (ResultVariable | SingleValuedPathExpression) ["ASC" | "DESC"]
GroupByItem ::= IdentificationVariable | SingleValuedPathExpression
NewValue ::= ScalarExpression | SimpleEntityExpression | "NULL"
IdentificationVariableDeclaration ::= RangeVariableDeclaration [IndexBy] {JoinVariableDeclaration}*
SubselectIdentificationVariableDeclaration ::= IdentificationVariableDeclaration | (AssociationPathExpression ["AS"] AliasIdentificationVariable)
JoinVariableDeclaration ::= Join [IndexBy]
RangeVariableDeclaration ::= AbstractSchemaName ["AS"] AliasIdentificationVariable
Join ::= ["LEFT" ["OUTER"] | "INNER"] "JOIN" JoinAssociationPathExpression ["AS"] AliasIdentificationVariable ["WITH" ConditionalExpression]
IndexBy ::= "INDEX" "BY" SimpleStateFieldPathExpression
SelectExpression ::= IdentificationVariable | PartialObjectExpression | (AggregateExpression | "(" Subselect ")" | FunctionDeclaration | ScalarExpression) [["AS"] AliasResultVariable]
SimpleSelectExpression ::= ScalarExpression | IdentificationVariable | (AggregateExpression [["AS"] AliasResultVariable])
PartialObjectExpression ::= "PARTIAL" IdentificationVariable "." PartialFieldSet
PartialFieldSet ::= "{" SimpleStateField {"," SimpleStateField}* "}"
ConditionalExpression ::= ConditionalTerm {"OR" ConditionalTerm}*
ConditionalTerm ::= ConditionalFactor {"AND" ConditionalFactor}*
ConditionalFactor ::= ["NOT"] ConditionalPrimary
ConditionalPrimary ::= SimpleConditionalExpression | "(" ConditionalExpression ")"
SimpleConditionalExpression ::= ComparisonExpression | BetweenExpression | LikeExpression | InExpression | NullComparisonExpression |
ExistsExpression | EmptyCollectionComparisonExpression | CollectionMemberExpression | InstanceOfExpression
EmptyCollectionComparisonExpression ::= CollectionValuedPathExpression "IS" ["NOT"] "EMPTY"
CollectionMemberExpression ::= EntityExpression ["NOT"] "MEMBER" ["OF"] CollectionValuedPathExpression
Literal ::= string | char | integer | float | boolean
InParameter ::= Literal | InputParameter
InputParameter ::= PositionalParameter | NamedParameter
PositionalParameter ::= "?" integer
NamedParameter ::= ":" string
ArithmeticExpression ::= SimpleArithmeticExpression | "(" Subselect ")"
SimpleArithmeticExpression ::= ArithmeticTerm {("+" | "-") ArithmeticTerm}*
ArithmeticTerm ::= ArithmeticFactor {("*" | "/") ArithmeticFactor}*
ArithmeticFactor ::= [("+" | "-")] ArithmeticPrimary
ArithmeticPrimary ::= SingleValuedPathExpression | Literal | "(" SimpleArithmeticExpression ")" | FunctionsReturningNumerics | AggregateExpression |
FunctionsReturningStrings | FunctionsReturningDatetime | IdentificationVariable | InputParameter | CaseExpression
ScalarExpression ::= SimpleArithmeticExpression | StringPrimary | DateTimePrimary | StateFieldPathExpression | BooleanPrimary | EntityTypeExpression | CaseExpression
StringExpression ::= StringPrimary | "(" Subselect ")"
StringPrimary ::= StateFieldPathExpression | string | InputParameter | FunctionsReturningStrings | AggregateExpression | CaseExpression
BooleanExpression ::= BooleanPrimary | "(" Subselect ")"
BooleanPrimary ::= StateFieldPathExpression | boolean | InputParameter
EntityExpression ::= SingleValuedAssociationPathExpression | SimpleEntityExpression
SimpleEntityExpression ::= IdentificationVariable | InputParameter
DatetimeExpression ::= DatetimePrimary | "(" Subselect ")"
DatetimePrimary ::= StateFieldPathExpression | InputParameter | FunctionsReturningDatetime | AggregateExpression
AggregateExpression ::= ("AVG" | "MAX" | "MIN" | "SUM") "(" ["DISTINCT"] StateFieldPathExpression ")" | "COUNT" "(" ["DISTINCT"] (IdentificationVariable | SingleValuedPathExpression) ")"
CaseExpression ::= GeneralCaseExpression | SimpleCaseExpression | CoalesceExpression | NullifExpression
GeneralCaseExpression ::= "CASE" WhenClause {WhenClause}* "ELSE" ScalarExpression "END"
WhenClause ::= "WHEN" ConditionalExpression "THEN" ScalarExpression
SimpleCaseExpression ::= "CASE" CaseOperand SimpleWhenClause {SimpleWhenClause}* "ELSE" ScalarExpression "END"
CaseOperand ::= StateFieldPathExpression | TypeDiscriminator
SimpleWhenClause ::= "WHEN" ScalarExpression "THEN" ScalarExpression
CoalesceExpression ::= "COALESCE" "(" ScalarExpression {"," ScalarExpression}* ")"
NullifExpression ::= "NULLIF" "(" ScalarExpression "," ScalarExpression ")"
QuantifiedExpression ::= ("ALL" | "ANY" | "SOME") "(" Subselect ")"
BetweenExpression ::= ArithmeticExpression ["NOT"] "BETWEEN" ArithmeticExpression "AND" ArithmeticExpression
ComparisonExpression ::= ArithmeticExpression ComparisonOperator ( QuantifiedExpression | ArithmeticExpression )
InExpression ::= StateFieldPathExpression ["NOT"] "IN" "(" (InParameter {"," InParameter}* | Subselect) ")"
InstanceOfExpression ::= IdentificationVariable ["NOT"] "INSTANCE" ["OF"] (InstanceOfParameter | "(" InstanceOfParameter {"," InstanceOfParameter}* ")")
InstanceOfParameter ::= AbstractSchemaName | InputParameter
LikeExpression ::= StringExpression ["NOT"] "LIKE" string ["ESCAPE" char]
NullComparisonExpression ::= (SingleValuedPathExpression | InputParameter) "IS" ["NOT"] "NULL"
ExistsExpression ::= ["NOT"] "EXISTS" "(" Subselect ")"
ComparisonOperator ::= "=" | "<" | "<=" | "<>" | ">" | ">=" | "!="
FunctionDeclaration ::= FunctionsReturningStrings | FunctionsReturningNumerics | FunctionsReturningDateTime
FunctionsReturningNumerics ::= "LENGTH" "(" StringPrimary ")" | "LOCATE" "(" StringPrimary "," StringPrimary ["," SimpleArithmeticExpression]")" | "ABS" "(" SimpleArithmeticExpression ")" |
"SQRT" "(" SimpleArithmeticExpression ")" | "MOD" "(" SimpleArithmeticExpression "," SimpleArithmeticExpression ")" | "SIZE" "(" CollectionValuedPathExpression ")"
FunctionsReturningDateTime ::= "CURRENT_DATE" | "CURRENT_TIME" | "CURRENT_TIMESTAMP"
FunctionsReturningStrings ::= "CONCAT" "(" StringPrimary "," StringPrimary ")" | "SUBSTRING" "(" StringPrimary "," SimpleArithmeticExpression "," SimpleArithmeticExpression ")" |
"TRIM" "(" [["LEADING" | "TRAILING" | "BOTH"] [char] "FROM"] StringPrimary ")" | "LOWER" "(" StringPrimary ")" | "UPPER" "(" StringPrimary ")"


Querying

Since the letter size is 6, you may still not believe me


Querying

let’s try a real world example!


Querying

Do you know Facebook activity wall?


Querying

Do you know Facebook activity wall?
Let’s show it!


SELECT e, a
FROM Entry e
JOIN e.wall w
JOIN e.user u
LEFT JOIN u.avatar av
WHERE u = :user
OR w IN (
SELECT uw
FROM UserWall uw
WHERE uw.user = :user
OR uw.user IN (
SELECT CASE WHEN ua = us.subscriber
THEN ub.id
ELSE ua.id
END
FROM UserSubscription us
JOIN us.friendship f
JOIN f.userA ua
JOIN f.userB ub
WHERE us.muted = FALSE
AND us.subscriber = :user
AND f.status = 'Approved'
)
)
OR w IN (
SELECT gw
FROM GroupWall gw
WHERE gw.group IN (
SELECT DISTINCT g.id
FROM GroupSubscription gs
JOIN gs.group g
WHERE gs.subscriber = :user
AND gs.muted = FALSE
AND gs.status = 'Approved'
)
)
ORDER BY e.created DESC

SELECT e, a
FROM Entry e
JOIN e.wall w Entry you wrote
JOIN e.user u
WHERE u = :user
OR w IN (
SELECT uw
FROM UserWall uw
OR uw.user IN (
THEN ub.id
ELSE ua.id
END
JOIN f.userA ua
JOIN f.userB ub
)
)
OR w IN (
SELECT gw
FROM GroupWall gw
WHERE gw.group IN (
JOIN gs.group g
)
)

SELECT e, a
FROM Entry e
JOIN e.user u
WHERE u = :user
OR w IN ( Entry was in your Wall
SELECT uw
FROM UserWall uw
OR uw.user IN (
THEN ub.id
ELSE ua.id
END
JOIN f.userA ua
JOIN f.userB ub
)
)
OR w IN (
SELECT gw
FROM GroupWall gw
WHERE gw.group IN (
JOIN gs.group g
)
)

SELECT e, a
FROM Entry e
JOIN e.user u
WHERE u = :user
SELECT uw
FROM UserWall uw
OR uw.user IN (
THEN ub.id
ELSE ua.id
END
User is your friend, the friendship is
JOIN us.friendship f approved and subscription is not muted
JOIN f.userA ua
JOIN f.userB ub
)
)
OR w IN (
SELECT gw
FROM GroupWall gw
WHERE gw.group IN (
JOIN gs.group g
)
)

SELECT e, a
FROM Entry e
JOIN e.user u
WHERE u = :user
SELECT uw
FROM UserWall uw
OR uw.user IN (
THEN ub.id
ELSE ua.id
END
User is your friend, the friendship is
JOIN us.friendship f approved and subscription is not muted
JOIN f.userA ua
JOIN f.userB ub
)
)
OR w IN (
SELECT gw
FROM GroupWall gw
WHERE gw.group IN (
JOIN gs.group g Group that you participate, is not
muted and have an approved status
)
)

Caching

http://www.ﬂickr.com/photos/eszter/3851576235/

Caching

Doctrine supports 3 levels of caching...


Caching

• Metadata cache
• Query cache
• Result cache


Caching

Cache mapping of entities

• Metadata cache
• Query cache
• Result cache


Caching


• Metadata cache
• Query cache Cache DQL to SQL conversion

• Result cache


Caching


• Metadata cache
• Query cache Cache DQL to SQL conversion

• Result cache
Cache PDO result set


Caching

    SELECT p
      FROM Post p
');

$query->useResultCache(true, 600, 'find-all-posts');



Indexing

http://www.ﬂickr.com/photos/osuarchives/2659419894/

Indexing

Doctrine is able to hint the Schema Tool to generate
database indexes on speciﬁed table columns


Indexing
/**
* @ORMEntity
* @ORMTable(
*     name = "users",
*     uniqueConstraints = {
*         @ORMUniqueConstraint(
*             name    = "user_unique",
*             columns = { "name" }
*         )
*     },
*     indexes = {
*         @ORMIndex(
*             name    = "login_idx",
*             columns = { "name", "password" }
*         )
*     }
* )
*/
class User
{
    // ...
}

Indexing

@ORMUniqueConstraint(
name = "user_unique",
columns = { "name" }
)

CREATE UNIQUE INDEX user_unique
ON TABLE users (name);


Indexing

@ORMIndex(
name = "login_idx",
columns = { "name", "password" }
)

CREATE INDEX login_idx
ON TABLE users (name, password);


Indexing

@ORMIndex(
name = "login_idx",
columns = { "name", "password" }
)
Some drivers restrict to
32 chars as index name

CREATE INDEX login_idx
ON TABLE users (name, password);


Inheritance

http://www.ﬂickr.com/photos/duanekeys/307005468/

Inheritance

Inheritance is a very deep topic in ORMs


Inheritance

Each inheritance type has advantages and disadvantages


Inheritance

• Concrete Table Inheritance
• Single Table Inheritance
• Class Table Inheritance


Inheritance

One Class, one Table



Inheritance


• Single Table Inheritance Multiple Classes, one Table


Inheritance


• Single Table Inheritance Multiple Classes, one Table
Multiple Classes, multiple Tables


Inheritance



Inheritance

• Pros


Inheritance

• Pros
• No locking problems


Inheritance

• Pros

• No irrelevant columns


Inheritance

• Pros


• Cons


Inheritance

• Pros


• Cons
• Difﬁcult to deal with primary keys


Inheritance

• Pros


• Cons

• Search base class means search all tables


Inheritance

• Pros


• Cons

• Search base class means search all tables

• Update on columns means update on all hierarchy tables


Inheritance
/**
* @ORMMappedSuperclass
*/
class Person
{
    /**
     * @ORMColumn(type="string", length=50)
     */
    protected $firstName;

    /**
     * @ORMColumn(type="string", length=50)
     */
    protected $lastName;
}

/**
* @ORMEntity
* @ORMTable(name="users")
*/
class User extends Person
{
    /**
     * @ORMId
     * @ORMGeneratedValue
     * @ORMColumn(type="integer")
     */
    protected $id;
}

Inheritance

CREATE TABLE users (
id INTEGER AUTO_INCREMENT NOT NULL,
firstName VARCHAR(50) NOT NULL,
lastName VARCHAR(50) NOT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB;


Inheritance



Inheritance

• Pros


Inheritance

• Pros
• Only one table for hierarchy


Inheritance

• Pros

• No joins


Inheritance

• Pros

• No joins

• Refactoring of ﬁelds means no change to database table


Inheritance

• Pros

• No joins


• Cons


Inheritance

• Pros

• No joins


• Cons
• Waste of space in database


Inheritance

• Pros

• No joins


• Cons

• Too many locks due to many accesses


Inheritance

• Pros

• No joins


• Cons

• Too many locks due to many accesses

• No duplicated ﬁeld names with different meanings


Inheritance
namespace MyAppEntity;

/**
* @ORMEntity
* @ORMTable(name= "people")
* @ORMInheritanceType("SINGLE_TABLE")
* @ORMDiscriminatorColumn(name="discr", type="string")
* @ORMDiscriminatorMap({
*     "user"     = "MyAppEntityUser",
*     "employee" = "MyAppEntityEmployee"
* })
*/
class User
{
    // ...
}

/**
* @ORMEntity
*/
class Employee extends User
{
     // ...
}


Inheritance

CREATE TABLE people (
id INT AUTO_INCREMENT NOT NULL,
discr VARCHAR(20) NOT NULL,
role VARCHAR(100) DEFAULT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB;


Inheritance



Inheritance

• Pros


Inheritance

• Pros
• Easy to understand


Inheritance

• Pros

• Database space is optimized due to table normalization


Inheritance

• Pros


• Direct relationship between Domain Model and Database


Inheritance

• Pros



• Cons


Inheritance

• Pros



• Cons
• Too many joins


Inheritance

• Pros



• Cons
• Too many joins

• Refactoring of ﬁelds needs a database schema update


Inheritance

• Pros



• Cons
• Too many joins

• Refactoring of ﬁelds needs a database schema update

• Superclass table accessed a lot, it means it may enter in lock mode


Inheritance
namespace MyAppEntity;

/**
* @ORMEntity
* @ORMTable(name="users")
* @ORMInheritanceType("JOINED")
* @ORMDiscriminatorColumn(
* name = "discr",
* type = "string",
* length = 20
* )
* @ORMDiscriminatorMap({
*     "user"     = "MyAppEntityUser",
*     "employee" = "MyAppEntityEmployee"
* })
*/
class User
{
    // ...
}

/**
* @ORMEntity
* @ORMTable(name= "employees")
*/
class Employee extends User
{
     // ...
}


Inheritance
CREATE TABLE users (
id INT AUTO_INCREMENT NOT NULL,
discr VARCHAR(20) NOT NULL,
PRIMARY KEY (id)
) ENGINE = InnoDB;

CREATE TABLE employees (
id INT NOT NULL,
role VARCHAR(100) NOT NULL,
PRIMARY KEY (id)
) ENGINE = InnoDB;

ALTER TABLE employees
ADD CONSTRAINT FK_BA82C300BF396750
FOREIGN KEY (id)
REFERENCES users (id)
ON DELETE CASCADE;


Inheritance

What’s the problem with inheritance?


Inheritance

What’s the problem with inheritance?
Hydration


Inheritance


Inheritance

• Inverse side *ToOne


Inheritance

• Owning side *ToOne with Inheritance


Inheritance

• Owning side *ToOne with Inheritance
• Disabled deferEagerLoad while Querying


Cascades

http://www.ﬂickr.com/photos/over_kind_man/3158552109/

Cascades

Ability to tell Unit Of Work of Doctrine how it should act
when inspecting an association for graph changes


Cascades

Use judiciously


Cascades

It can heavily increase the graph edges to be navigated
once the Compute Changeset algorithm is ran


Cascades

This means more time to
persist, delete, merge, detach, refresh...


Cascades
/**
* @ORMEntity
*/
class User
{
    //...

    /**
     * Bidirectional - One-To-Many (INVERSE SIDE)
     *
     * @ORMOneToMany(
     *     targetEntity = "Comment",
     *     mappedBy     = "author",
     *     cascade = { "persist", "remove" }
     * )
     */
    protected $commentsAuthored;
}


Hydrators

http://crimsonnightstock.deviantart.com/art/Yellow-Fire-Hydrant-Stock-100121929

Hydrators

Doctrine comes with some useful result hydrators


Hydrators

This means that not all times you need to retrieve objects


Hydrators

• Object
• Array
• Scalar
• Iterable
• Simple Object
• Single Scalar


Hydrators

• Object $resultList = $query->getResult();

• Array
• Scalar
• Iterable
• Simple Object
• Single Scalar


Hydrators


• Array $resultArray = $query->getArrayResult();

• Scalar
• Iterable
• Simple Object
• Single Scalar


Hydrators



• Scalar $result = $query->getScalarResult();

• Iterable
• Simple Object
• Single Scalar


Hydrators




• Iterable $iterator = $query->iterate();

• Simple Object
• Single Scalar


Hydrators





• Simple Object $result = $query->getSingleResult();

• Single Scalar


Hydrators





• Simple Object $result = $query->getSingleResult();

• Single Scalar $result = $query->getSingleScalarResult();


http://joind.in/6053

Questions?

@guilhermeblanco


InstaClick Inc.



Questions?

@guilhermeblanco


InstaClick Inc. We are hiring! Talk to me privately if interested



Questions?
Thank you!

@guilhermeblanco


InstaClick Inc. We are hiring! Talk to me privately if interested


ORM dont kill your DB, developers do

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