Basic Mapping
This guide explains the basic mapping of entities and properties. After working through this guide you should know:
- How to create PHP objects that can be saved to the database with Doctrine;
- How to configure the mapping between columns on tables and properties on entities;
- What Doctrine mapping types are;
- Defining primary keys and how identifiers are generated by Doctrine;
- How quoting of reserved symbols works in Doctrine.
Mapping of associations will be covered in the next chapter on Association Mapping.
Creating Classes for the Database
Every PHP object that you want to save in the database using Doctrine is called an Entity. The term Entity describes objects that have an identity over many independent requests. This identity is usually achieved by assigning a unique identifier to an entity. In this tutorial the following Message PHP class will serve as the example Entity:
1 class Message < private $id; private $text; private $postedAt; > 2 3 4 5 6 7
Because Doctrine is a generic library, it only knows about your entities because you will describe their existence and structure using mapping metadata, which is configuration that tells Doctrine how your entity should be stored in the database. The documentation will often speak of mapping something, which means writing the mapping metadata that describes your entity.
Doctrine provides several different ways to specify object-relational mapping metadata:
- Attributes
- XML
- PHP code
- Docblock Annotations (deprecated and will be removed in doctrine/orm 3.0)
- YAML (deprecated and will be removed in doctrine/orm 3.0.)
This manual will usually show mapping metadata via attributes, though many examples also show the equivalent configuration in annotations, YAML and XML.
All metadata drivers perform equally. Once the metadata of a class has been read from the source (attributes, annotations, XML, etc.) it is stored in an instance of the Doctrine\ORM\Mapping\ClassMetadata class which are stored in the metadata cache. If you’re not using a metadata cache (not recommended!) then the XML driver is the fastest.
Marking our Message class as an entity for Doctrine is straightforward:
1 use Doctrine\ORM\Mapping\Entity; #[Entity] class Message < // . > 2 3 4 5 6 7 8
1 use Doctrine\ORM\Mapping\Entity; /** @Entity */ class Message < // . > 2 3 4 5 6 7 8
1 doctrine-mapping> entity name="Message"> entity> doctrine-mapping> 2 3 4 5
1 Message: type: entity # . 2 3
With no additional information, Doctrine expects the entity to be saved into a table with the same name as the class in our case Message . You can change this by configuring information about the table:
1 use Doctrine\ORM\Mapping\Entity; use Doctrine\ORM\Mapping\Table; #[Entity] #[Table(name: 'message')] class Message < // . > 2 3 4 5 6 7 8 9 10
1 use Doctrine\ORM\Mapping\Entity; use Doctrine\ORM\Mapping\Table; /** * @Entity * @Table(name="message") */ class Message < // . > 2 3 4 5 6 7 8 9 10 11 12
1 doctrine-mapping> entity name="Message" table="message"> entity> doctrine-mapping> 2 3 4 5
1 Message: type: entity table: message # . 2 3 4
Now the class Message will be saved and fetched from the table message .
Property Mapping
The next step is mapping its properties to columns in the table.
To configure a property use the Column attribute. The type argument specifies the Doctrine Mapping Type to use for the field. If the type is not specified, string is used as the default.
1 use Doctrine\ORM\Mapping\Column; use Doctrine\DBAL\Types\Types; #[Entity] class Message < #[Column(type: Types::INTEGER)] private $id; #[Column(length: 140)] private $text; #[Column(name: 'posted_at', type: Types::DATETIME)] private $postedAt; > 2 3 4 5 6 7 8 9 10 11 12 13 14
1 use Doctrine\ORM\Mapping\Entity; use Doctrine\ORM\Mapping\Column; /** @Entity */ class Message < /** @Column(type="integer") */ private $id; /** @Column(length=140) */ private $text; /** @Column(type="datetime", name="posted_at") */ private $postedAt; > 2 3 4 5 6 7 8 9 10 11 12 13 14
1 doctrine-mapping> entity name="Message"> field name="id" type="integer" /> field name="text" length="140" /> field name="postedAt" column="posted_at" type="datetime" /> entity> doctrine-mapping> 2 3 4 5 6 7
1 Message: type: entity fields: id: type: integer text: length: 140 postedAt: type: datetime column: posted_at 2 3 4 5 6 7 8 9 10
When we don’t explicitly specify a column name via the name option, Doctrine assumes the field name is also the column name. So in this example:
- the id property will map to the column id using the type integer ;
- the text property will map to the column text with the default mapping type string ;
- the postedAt property will map to the posted_at column with the datetime type.
Here is a complete list of Column s attributes (all optional):
- type (default: ‘string’): The mapping type to use for the column.
- name (default: name of property): The name of the column in the database.
- length (default: 255): The length of the column in the database. Applies only if a string-valued column is used.
- unique (default: false ): Whether the column is a unique key.
- nullable (default: false ): Whether the column is nullable.
- insertable (default: true ): Whether the column should be inserted.
- updatable (default: true ): Whether the column should be updated.
- enumType (requires PHP 8.1 and doctrine/orm 2.11): The PHP enum class name to convert the database value into.
- precision (default: 0): The precision for a decimal (exact numeric) column (applies only for decimal column), which is the maximum number of digits that are stored for the values.
- scale (default: 0): The scale for a decimal (exact numeric) column (applies only for decimal column), which represents the number of digits to the right of the decimal point and must not be greater than precision .
- columnDefinition : Allows to define a custom DDL snippet that is used to create the column. Warning: This normally confuses the SchemaTool to always detect the column as changed.
- options : Key-value pairs of options that get passed to the underlying database platform when generating DDL statements.
PHP Types Mapping
New in version 2.9
The column types can be inferred automatically from PHP’s property types. However, when the property type is nullable this has no effect on the nullable Column attribute.
These are the automatic mapping rules:
| PHP property type | Doctrine column type |
|---|---|
| DateInterval | Types::DATEINTERVAL |
| DateTime | Types::DATETIME_MUTABLE |
| DateTimeImmutable | Types::DATETIME_IMMUTABLE |
| array | Types::JSON |
| bool | Types::BOOLEAN |
| float | Types::FLOAT |
| int | Types::INTEGER |
| Any other type | Types::STRING |
As of version 2.11 Doctrine can also automatically map typed properties using a PHP 8.1 enum to set the right type and enumType .
New in version 2.14
Since version 2.14 you can specify custom typed field mapping between PHP type and DBAL type using Configuration and a custom Doctrine\ORM\Mapping\TypedFieldMapper implementation.
Doctrine Mapping Types
The type option used in the @Column accepts any of the existing Doctrine types or even your own custom types. A Doctrine type defines the conversion between PHP and SQL types, independent from the database vendor you are using. All Mapping Types that ship with Doctrine are fully portable between the supported database systems.
As an example, the Doctrine Mapping Type string defines the mapping from a PHP string to a SQL VARCHAR (or VARCHAR2 etc. depending on the RDBMS brand). Here is a quick overview of the built-in mapping types:
- string : Type that maps a SQL VARCHAR to a PHP string.
- integer : Type that maps a SQL INT to a PHP integer.
- smallint : Type that maps a database SMALLINT to a PHP integer.
- bigint : Type that maps a database BIGINT to a PHP string.
- boolean : Type that maps a SQL boolean or equivalent (TINYINT) to a PHP boolean.
- decimal : Type that maps a SQL DECIMAL to a PHP string.
- date : Type that maps a SQL DATETIME to a PHP DateTime object.
- time : Type that maps a SQL TIME to a PHP DateTime object.
- datetime : Type that maps a SQL DATETIME/TIMESTAMP to a PHP DateTime object.
- datetimetz : Type that maps a SQL DATETIME/TIMESTAMP to a PHP DateTime object with timezone.
- text : Type that maps a SQL CLOB to a PHP string.
- object : Type that maps a SQL CLOB to a PHP object using serialize() and unserialize()
- array : Type that maps a SQL CLOB to a PHP array using serialize() and unserialize()
- simple_array : Type that maps a SQL CLOB to a PHP array using implode() and explode() , with a comma as delimiter. IMPORTANT Only use this type if you are sure that your values cannot contain a «,».
- json_array : Type that maps a SQL CLOB to a PHP array using json_encode() and json_decode()
- float : Type that maps a SQL Float (Double Precision) to a PHP double. IMPORTANT: Works only with locale settings that use decimal points as separator.
- guid : Type that maps a database GUID/UUID to a PHP string. Defaults to varchar but uses a specific type if the platform supports it.
- blob : Type that maps a SQL BLOB to a PHP resource stream
A cookbook article shows how to define your own custom mapping types.
DateTime and Object types are compared by reference, not by value. Doctrine updates this values if the reference changes and therefore behaves as if these objects are immutable value objects.
All Date types assume that you are exclusively using the default timezone set by date_default_timezone_set() or by the php.ini configuration date.timezone . Working with different timezones will cause troubles and unexpected behavior.
If you need specific timezone handling you have to handle this in your domain, converting all the values back and forth from UTC. There is also a cookbook entry on working with datetimes that gives hints for implementing multi timezone applications.
Identifiers / Primary Keys
Every entity class must have an identifier/primary key. You can select the field that serves as the identifier with the #[Id] attribute.
1 class Message < #[Id] #[Column(type: 'integer')] #[GeneratedValue] private int|null $id = null; // . > 2 3 4 5 6 7 8 9
1 class Message < /** * @Id * @Column(type="integer") * @GeneratedValue */ private int|null $id = null; // . > 2 3 4 5 6 7 8 9 10 11
1 doctrine-mapping> entity name="Message"> id name="id" type="integer"> generator strategy="AUTO" /> id> entity> doctrine-mapping> 2 3 4 5 6 7 8
1 Message: type: entity id: id: type: integer generator: strategy: AUTO fields: # fields here 2 3 4 5 6 7 8 9
In most cases using the automatic generator strategy ( #[GeneratedValue] ) is what you want. It defaults to the identifier generation mechanism your current database vendor prefers: AUTO_INCREMENT with MySQL, sequences with PostgreSQL and Oracle and so on.
Identifier Generation Strategies
The previous example showed how to use the default identifier generation strategy without knowing the underlying database with the AUTO-detection strategy. It is also possible to specify the identifier generation strategy more explicitly, which allows you to make use of some additional features.
Here is the list of possible generation strategies:
- AUTO (default): Tells Doctrine to pick the strategy that is preferred by the used database platform. The preferred strategies are IDENTITY for MySQL, SQLite, MsSQL and SQL Anywhere and SEQUENCE for Oracle and PostgreSQL. This strategy provides full portability.
- SEQUENCE : Tells Doctrine to use a database sequence for ID generation. This strategy does currently not provide full portability. Sequences are supported by Oracle, PostgreSql and SQL Anywhere.
- IDENTITY : Tells Doctrine to use special identity columns in the database that generate a value on insertion of a row. This strategy does currently not provide full portability and is supported by the following platforms: MySQL/SQLite/SQL Anywhere (AUTO_INCREMENT), MSSQL (IDENTITY) and PostgreSQL (SERIAL).
- UUID (deprecated): Tells Doctrine to use the built-in Universally Unique Identifier generator. This strategy provides full portability.
- NONE : Tells Doctrine that the identifiers are assigned (and thus generated) by your code. The assignment must take place before a new entity is passed to EntityManager#persist . NONE is the same as leaving off the #[GeneratedValue] entirely.
- CUSTOM : With this option, you can use the #[CustomIdGenerator] attribute. It will allow you to pass a class of your own to generate the identifiers.
Sequence Generator
The Sequence Generator can currently be used in conjunction with Oracle or Postgres and allows some additional configuration options besides specifying the sequence’s name:
1 class Message < #[Id] #[GeneratedValue(strategy: 'SEQUENCE')] #[SequenceGenerator(sequenceName: 'message_seq', initialValue: 1, allocationSize: 100)] protected int|null $id = null; // . > 2 3 4 5 6 7 8 9
1 class Message < /** * @Id * @GeneratedValue(strategy="SEQUENCE") * @SequenceGenerator(sequenceName="message_seq", initialValue=1, allocationSize=100) */ protected int|null $id = null; // . > 2 3 4 5 6 7 8 9 10 11
1 doctrine-mapping> entity name="Message"> id name="id" type="integer"> generator strategy="SEQUENCE" /> sequence-generator sequence-name="message_seq" allocation-size="100" initial-value="1" /> id> entity> doctrine-mapping> 2 3 4 5 6 7 8
1 Message: type: entity id: id: type: integer generator: strategy: SEQUENCE sequenceGenerator: sequenceName: message_seq allocationSize: 100 initialValue: 1 2 3 4 5 6 7 8 9 10 11
The initial value specifies at which value the sequence should start.
The allocationSize is a powerful feature to optimize INSERT performance of Doctrine. The allocationSize specifies by how much values the sequence is incremented whenever the next value is retrieved. If this is larger than 1 (one) Doctrine can generate identifier values for the allocationSizes amount of entities. In the above example with allocationSize=100 Doctrine ORM would only need to access the sequence once to generate the identifiers for 100 new entities.
The allocationSize is detected by SchemaTool and transformed into an INCREMENT BY clause in the CREATE SEQUENCE statement. For a database schema created manually (and not SchemaTool) you have to make sure that the allocationSize configuration option is never larger than the actual sequences INCREMENT BY value, otherwise you may get duplicate keys.
It is possible to use strategy=AUTO and at the same time specifying a @SequenceGenerator. In such a case, your custom sequence settings are used in the case where the preferred strategy of the underlying platform is SEQUENCE, such as for Oracle and PostgreSQL.
Composite Keys
With Doctrine ORM you can use composite primary keys, using #[Id] on more than one column. Some restrictions exist opposed to using a single identifier in this case: The use of the #[GeneratedValue] attribute is not supported, which means you can only use composite keys if you generate the primary key values yourself before calling EntityManager#persist() on the entity.
More details on composite primary keys are discussed in a dedicated tutorial.
Quoting Reserved Words
Sometimes it is necessary to quote a column or table name because of reserved word conflicts. Doctrine does not quote identifiers automatically, because it leads to more problems than it would solve. Quoting tables and column names needs to be done explicitly using ticks in the definition.
1 #[Column(name: '`number`', type: 'integer')] private $number; 2 3 4
Doctrine will then quote this column name in all SQL statements according to the used database platform.
Identifier Quoting does not work for join column names or discriminator column names unless you are using a custom QuoteStrategy .
For more control over column quoting the Doctrine\ORM\Mapping\QuoteStrategy interface was introduced in ORM. It is invoked for every column, table, alias and other SQL names. You can implement the QuoteStrategy and set it by calling Doctrine\ORM\Configuration#setQuoteStrategy() .
The ANSI Quote Strategy was added, which assumes quoting is not necessary for any SQL name. You can use it with the following code:
1 use Doctrine\ORM\Mapping\AnsiQuoteStrategy; $configuration->setQuoteStrategy(new AnsiQuoteStrategy()); 2 3 4
What are Automatic Properties in C# and what is their purpose?
Could someone provide a very simple explanation of Automatic Properties in C#, their purpose, and maybe some examples? Try to keep things in layman’s terms, please!
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asked May 14, 2011 at 12:45
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possible duplicate of C# 3.0 auto-properties — useful or not?
Jun 3, 2013 at 19:02
11 Answers 11
Automatic Properties are used when no additional logic is required in the property accessors.
The declaration would look something like this:
public int SomeProperty
They are just syntactic sugar so you won’t need to write the following more lengthy code:
private int _someField; public int SomeProperty < get < return _someField;>set < _someField = value;>>
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answered May 14, 2011 at 12:51
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@Cody Gray @Stecya Why can’t i just use public int SomeProperty; Will this not be the same? I mean if there is no private variable at all here, then why do we even need Properties?
Nov 7, 2016 at 17:35
@user2048204 because property is different from variable blog.codinghorror.com/properties-vs-public-variables
Nov 18, 2016 at 16:40
when you explore an auto-implemented property with ildasm tool, you’ll come to know that behind each auto-implemented property there are following field created automatically a private data member and two methods that work as getter and setter for that private field.
Jul 28, 2018 at 7:17
There’s something missing from Stecya/AustinWBryan’s answer. if an autoproperty creates a private field behind the scenes, why is is that an interface can define an autoproperty but not fields? It can’t be the case that autoproproperties are «just» syntactic sugar, because it it was there would be compiler errors when I use them in interfaces.
Jan 28, 2019 at 9:27
It’s astonishing that out of this 5 replies in this thread nobody answered the question, which is «why do we even need Properties». He wasn’t asking how it works «under the hood», but for it’s practical purposes. I think when you don’t have an actual reason to use a property (such as implementing an interface, or using reflection) you indeed better of making the field public and be done with it. You don’t need the getter-setter if do nothing with them.
Nov 16, 2021 at 16:19
Edit: Expanding a little, these are used to make it easier to have private variables in the class, but allow them to be visible to outside the class (without being able to modify them)
Oh, and another advantage with automatic properties is you can use them in interfaces! (Which don’t allow member variables of any kind)
With normal properties, you can do something like:
private string example; public string Example < get < return example; >set < example = value; >> Automatic properties allows you to create something really concise:
public string Example
So if you wanted to create a field where it was only settable inside the class, you could do:
public string Example
This would be equivalent to:
private string example; public string Example < get < return example; >private set < example = value; >> private String example; public String getExample() < return example; >private void setExample(String value)
Edit: @Paya also alerted me to:
- http://msdn.microsoft.com/en-us/library/bb384054.aspx
- http://weblogs.asp.net/dwahlin/archive/2007/12/04/c-3-0-features-automatic-properties.aspx
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answered May 14, 2011 at 12:50
Darkzaelus Darkzaelus
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I would also add these two links: MSDN and ASP.NET Blog.
May 14, 2011 at 12:51
The equivalent in Java would need setExample to be private or no setter at all.
Aug 2, 2017 at 8:16
This should be the selected answer, as the current one provides no actual reason to use empty get/get over using a simple field (said abruptly, it just states there is a simple way to declare useless methods).
Mar 26, 2019 at 8:25
If you are asking why you would use Properties or Automatic Properties, this is the design philosophy behind it.
One important design principle is that you never expose fields as public, but rather always access everything via properties. This is because you can never tell when a field is accessed and more importantly when it is set. Now, a lot of the time, there is never any processing needed while setting or getting the value (for example, range checking). This is why Automatic Properties were created. They are a simple, one-line way of creating a property. The backing store for it is created by the compiler.
While this is what I do even for my internal programs, it is probably more important for ones designed for public use (for sale, open source, etc). If you use an Automatic Property and later decide that you need to do something else in the set or get , you can easily change your code without breaking the public interface.
Update
As a point of clarification to a comment below, if all of the code is your own, then no, it may not make much of a difference between a property and a field to you. But, if you are designing a library that will be consumed by others then switching back and forth between public fields and properties will cause exceptions unless the code using the library is recompiled first.
As a test, I created a library project and declared a property called TestData . I created a whole new project just to consume this library. All worked as expected. I then changed the property to a public field (the name stayed the same) and copied over the new library DLL without recompiling the consuming project. The outcome was an exception thrown as the code was expecting to find the methods property methods get_TestData and set_TestData , but fields are not accessed via methods.
Unhandled Exception: System.MissingMethodException: Method not found: 'Void TestLibrary.TesterClass.set_TestData(System.String)'. at TestLibraryConsumer.Program.Main(String[] args) Data streamsedit
A data stream lets you store append-only time series data across multiple indices while giving you a single named resource for requests. Data streams are well-suited for logs, events, metrics, and other continuously generated data.
You can submit indexing and search requests directly to a data stream. The stream automatically routes the request to backing indices that store the stream’s data. You can use index lifecycle management (ILM) to automate the management of these backing indices. For example, you can use ILM to automatically move older backing indices to less expensive hardware and delete unneeded indices. ILM can help you reduce costs and overhead as your data grows.
Backing indicesedit
A data stream consists of one or more hidden, auto-generated backing indices.
A data stream requires a matching index template. The template contains the mappings and settings used to configure the stream’s backing indices.
Every document indexed to a data stream must contain a @timestamp field, mapped as a date or date_nanos field type. If the index template doesn’t specify a mapping for the @timestamp field, Elasticsearch maps @timestamp as a date field with default options.
The same index template can be used for multiple data streams. You cannot delete an index template in use by a data stream.
The name pattern for the backing indices is an implementation detail and no intelligence should be derived from it. The only invariant the holds is that each data stream generation index will have a unique name.
Read requestsedit
When you submit a read request to a data stream, the stream routes the request to all its backing indices.
Write indexedit
The most recently created backing index is the data stream’s write index. The stream adds new documents to this index only.
You cannot add new documents to other backing indices, even by sending requests directly to the index.
You also cannot perform operations on a write index that may hinder indexing, such as:
Rolloveredit
A rollover creates a new backing index that becomes the stream’s new write index.
We recommend using ILM to automatically roll over data streams when the write index reaches a specified age or size. If needed, you can also manually roll over a data stream.
Generationedit
Each data stream tracks its generation: a six-digit, zero-padded integer starting at 000001 .
When a backing index is created, the index is named using the following convention:
is the backing index’s creation date. Backing indices with a higher generation contain more recent data. For example, the web-server-logs data stream has a generation of 34 . The stream’s most recent backing index, created on 7 March 2099, is named .ds-web-server-logs-2099.03.07-000034 .
Some operations, such as a shrink or restore, can change a backing index’s name. These name changes do not remove a backing index from its data stream.
The generation of the data stream can change without a new index being added to the data stream (e.g. when an existing backing index is shrunk). This means the backing indices for some generations will never exist. You should not derive any intelligence from the backing indices names.
Append-onlyedit
Data streams are designed for use cases where existing data is rarely, if ever, updated. You cannot send update or deletion requests for existing documents directly to a data stream. Instead, use the update by query and delete by query APIs.
If needed, you can update or delete documents by submitting requests directly to the document’s backing index.
If you frequently update or delete existing time series data, use an index alias with a write index instead of a data stream. See Manage time series data without data streams.
Autogenerated properties что это
Automatic numbering is supported in Windchill Workgroup Manager for CATIA 3DEXPERIENCE and is enabled by default. Whenever a new CAD document is created from CATIA 3DEXPERIENCE (directly or by using a Save As action), a number generated from Windchill is automatically assigned to the title of the document. This title is unique in Windchill and by default, is also used as the number of the corresponding EPM document in Windchill once the CAD document is checked in.
With auto-numbering enabled, you can accept the auto-generated number, or enter a custom value for the title. If a CAD document was previously created in CATIA 3DEXPERIENCE using auto-numbering, you can change the part number in the native Properties window.
The following conditions are required for proper operation of auto-numbering.
• The CAD tool is connected to Windchill Workgroup Manager for CATIA 3DEXPERIENCE .
• Windchill Workgroup Manager for CATIA 3DEXPERIENCE has an active Windchill server registered.
• If you want to disable auto-numbering, set the Windchill preference Sychronize Number and File Name to No for CATIA 3DEXPERIENCE . For more information, see Preferences Managed in the Windchill Preference Management Utility .
• When automatic numbering is disabled, the title of a new CAD document is based on the native CATIA 3DEXPERIENCE configuration setting.
Other Preference Settings
Consider how the following preferences in the Windchill Preference Management utility affect auto-numbering.
• CAD Document Number System Attribute —Set this to identify the system property in CATIA 3DEXPERIENCE that shows the CAD document number.
• Synchronize Number and File Name —Set this to No for CATIA 3DEXPERIENCE if you want to disable automatic numbering.
• Drop File Extension From Name —Set this to Yes for CATIA 3DEXPERIENCE if you want an auto-generated Windchill part name that does not include the file extension.
• Drop File Extension From Number —Set this to Yes for CATIA 3DEXPERIENCE if you want an auto-generated Windchill part number that does not include the file extension.
• Naming Parameter —Set this to specify the CATIA 3DEXPERIENCE designated parameter from which the CAD document name is copied.
• Numbering Parameter —Set this to specify the CATIA 3DEXPERIENCE designated parameter from which the CAD document number is copied.
For more information about Windchill Workgroup Manager preferences for CATIA 3DEXPERIENCE , see Preferences for CATIA 3DEXPERIENCE .