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authorxue <>2007-08-20 12:09:02 +0000
committerxue <>2007-08-20 12:09:02 +0000
commitd33132b9cf27f0213562896033dc52565c8318f9 (patch)
tree316d17346064ad4d4c4af907a9d5d6edad780302 /demos/quickstart/protected/pages/Database
parent751af79e8cd79eaedfa68a622f871797f8697ed0 (diff)
fixed typos.
Diffstat (limited to 'demos/quickstart/protected/pages/Database')
-rw-r--r--demos/quickstart/protected/pages/Database/ActiveRecord.page224
-rw-r--r--demos/quickstart/protected/pages/Database/SqlMap.page86
2 files changed, 155 insertions, 155 deletions
diff --git a/demos/quickstart/protected/pages/Database/ActiveRecord.page b/demos/quickstart/protected/pages/Database/ActiveRecord.page
index c97711d6..e5ddcdfd 100644
--- a/demos/quickstart/protected/pages/Database/ActiveRecord.page
+++ b/demos/quickstart/protected/pages/Database/ActiveRecord.page
@@ -4,43 +4,43 @@
<com:SinceVersion Version="3.1a" />
<p id="690478" class="block-content">Active Records are objects that wrap a row in a database table or view,
encapsulate the database access and add domain logic on that data.
- The basics of an Active Record are business classes, e.g., a
+ The basics of an Active Record are business classes, e.g., a
<tt>Products</tt> class, that match very closely the record structure
of an underlying database table. Each Active Record will be responsible for
saving and loading data to and from the database. </p>
<div class="info"><b class="note">Info:</b>
- The data structure of an Active Record should match that of a table
+ The data structure of an Active Record should match that of a table
in the database.
Each column of a table should have a corresponding member variable or property in the
Active Record class the represents the table.
</div>
<h2 id="138047">When to Use It</h2>
-<p id="690479" class="block-content">Active Record is a good choice for domain logic that isn't too complex,
+<p id="690479" class="block-content">Active Record is a good choice for domain logic that isn't too complex,
such as creates, reads, updates, and deletes. Derivations and validations
based on a single record work well in this structure. Active Record has the
- primary advantage of simplicity. It's easy to build
+ primary advantage of simplicity. It's easy to build
Active Records, and they are easy to understand.</p>
- <p id="690480" class="block-content">However, as your business logic grows in complexity, you'll soon want
+ <p id="690480" class="block-content">However, as your business logic grows in complexity, you'll soon want
to use your object's direct relationships, collections, inheritance, and so
- forth. These don't map easily onto Active Record, and adding them piecemeal
+ forth. These don't map easily onto Active Record, and adding them piecemeal
gets very messy.
- Another argument against Active Record is the fact that it couples the object
+ Another argument against Active Record is the fact that it couples the object
design to the database design. This makes it more difficult to refactor as a project goes forward.</p>
-
+
<p id="690481" class="block-content">The alternative is to use a Data Mapper that separates the roles of the
- business object and how these objects are stored.
- Prado provides a complimentary choice between Active Record and
- <a href="?page=Database.SqlMap">SqlMap Data Mapper</a>.
+ business object and how these objects are stored.
+ Prado provides a complimentary choice between Active Record and
+ <a href="?page=Database.SqlMap">SqlMap Data Mapper</a>.
A SqlMap Data Mapper can be used to load Active Record objects, in turn; these
- Active Record objects can be used to update the database.
+ Active Record objects can be used to update the database.
The "relationship" between Active Records and <a href="?page=Database.SqlMap">SqlMap</a> is illustrated in the
following diagram. More details regarding the SqlMap Data Mapper can be found in
the <a href="http://www.pradosoft.com/demos/sqlmap/">SqlMap Manual</a>.
<img src=<%~ sqlmap_active_record.png %> alt="Active Records and SqlMap DataMapper" id="fig:diagram.png" class="figure"/>
</p>
-
+
<p id="690482" class="block-content">
The Active Record class has functionality to perform the following tasks.
</p>
@@ -52,8 +52,8 @@
</ul>
<h2 id="142010">Database Supported</h2>
<p id="p1" class="block-content">
-The Active Record implementation utilizes the <a href="?page=Database.DAO">Prado DAO</a> classes for data access.
-The current Active Record implementation supports the following database.
+The Active Record implementation utilizes the <a href="?page=Database.DAO">Prado DAO</a> classes for data access.
+The current Active Record implementation supports the following database.
</p>
<ul>
<li><a href="http://www.mysql.com">MySQL 4.1 or later</a></li>
@@ -66,8 +66,8 @@ The current Active Record implementation supports the following database.
<h1 id="138048">Defining an Active Record</h1>
<p id="690483" class="block-content">Let us
- consider the following "<tt>users</tt>" table that contains two columns named "<tt>username</tt>" and "<tt>email</tt>",
- where "<tt>username</tt>" is also the primary key.
+ consider the following "<tt>users</tt>" table that contains two columns named "<tt>username</tt>" and "<tt>email</tt>",
+ where "<tt>username</tt>" is also the primary key.
<com:TTextHighlighter Language="sql" CssClass="source block-content" id="code_690147">
CREATE TABLE users
(
@@ -81,11 +81,11 @@ CREATE TABLE users
<com:TTextHighlighter Language="php" CssClass="source block-content" id="code_690148">
class UserRecord extends TActiveRecord
{
- const TABLE='users'; //table name
+ const TABLE='users'; //table name
public $username; //the column named "username" in the "users" table
public $email;
-
+
/**
* @return TActiveRecord active record finder instance
*/
@@ -96,7 +96,7 @@ class UserRecord extends TActiveRecord
}
</com:TTextHighlighter>
</p>
-<p id="690485" class="block-content">Each column of the "<tt>users</tt>" table must have corresponding
+<p id="690485" class="block-content">Each column of the "<tt>users</tt>" table must have corresponding
property of the same name as the column name in the <tt>UserRecord</tt> class.
Of course, you also define additional member variables or properties that does not exist in the table structure.
The class constant
@@ -117,7 +117,7 @@ You may specify qualified table names. E.g. for MySQL, <tt>TABLE = "`database1`.
<com:TTextHighlighter Language="php" CssClass="source block-content" id="code_690149">
class UserRecord extends TActiveRecord {
... //existing definitions as above
-
+
private $_level;
public function setLevel($value) {
$this->_level=TPropertyValue::ensureInteger($value,0);
@@ -135,13 +135,13 @@ Later we shall use the getter/setters to allow for lazy loading of relationship
<tt>TActiveRecord</tt> can also work with database views by specifying the constant <tt>TABLE</tt>
corresponding to the view name. However, objects returned
from views are read-only, calling the <tt>save()</tt> or <tt>delete()</tt> method
-will raise an exception.
+will raise an exception.
</div>
<p id="690486" class="block-content">
The static method <tt>finder()</tt> returns an <tt>UserRecord</tt> instance
that can be used to load records from the database. The loading of records
- using the finer methods is discussed a little later. The <tt>TActiveRecord::finder()</tt>
+ using the finder methods is discussed a little later. The <tt>TActiveRecord::finder()</tt>
static method takes the name of an Active Record class as parameter.
</p>
@@ -156,11 +156,11 @@ will raise an exception.
$dsn = 'pgsql:host=localhost;dbname=test'; //Postgres SQL
$conn = new TDbConnection($dsn, 'dbuser','dbpass');
TActiveRecordManager::getInstance()->setDbConnection($conn);
-</com:TTextHighlighter>
+</com:TTextHighlighter>
<p id="710011" class="block-content">Alternatively, you can create a base class and override the <tt>getDbConnection()</tt>
method to return a database connection. This is a simple way to permit multiple
-connections and multiple databases. The following code demonstrates defining
+connections and multiple databases. The following code demonstrates defining
the database connection in a base class (not need to set the DB connection anywhere else).
</p>
<com:TTextHighlighter Language="php" CssClass="source block-content">
@@ -184,14 +184,14 @@ class MyDb2Record extends TActiveRecord
return $conn;
}
}
-</com:TTextHighlighter>
+</com:TTextHighlighter>
<h3 class="prado-specific">Using <tt>application.xml</tt> within the Prado Framework</h3>
<div class="prado-specific">
<p id="690488" class="block-content">
The default database connection can also be configured using a <tt>&lt;module&gt;</tt>
- tag in the <a href="?page=Configurations.AppConfig">application.xml</a>
+ tag in the <a href="?page=Configurations.AppConfig">application.xml</a>
or <a href="?page=Configurations.PageConfig">config.xml</a> as follows.
<com:TTextHighlighter Language="xml" CssClass="source block-content" id="code_690151">
<modules>
@@ -199,8 +199,8 @@ class MyDb2Record extends TActiveRecord
<database ConnectionString="pgsql:host=localhost;dbname=test"
Username="dbuser" Password="dbpass" />
</module>
-</modules>
-</com:TTextHighlighter>
+</modules>
+</com:TTextHighlighter>
<div class="tip"><b class="note">Tip:</b>
The <tt>EnableCache</tt> attribute when set to "true" will cache the table
meta data, that is, the table columns names, indexes and constraints are
@@ -220,20 +220,20 @@ class MyDb2Record extends TActiveRecord
Username="dbuser" Password="dbpass" />
</module>
- <module class="System.Data.ActiveRecord.TActiveRecordConfig"
+ <module class="System.Data.ActiveRecord.TActiveRecordConfig"
ConnectionID="db1" EnableCache="true" />
<module class="System.Data.SqlMap.TSqlMapConfig"
ConnectionID="db1" ... />
-</modules>
-</com:TTextHighlighter>
+</modules>
+</com:TTextHighlighter>
</p>
</div>
<h2 id="138050">Loading data from the database</h2>
<p id="690490" class="block-content">
The <tt>TActiveRecord</tt> class provides many convenient methods to find
- records from the database. The simplest is finding one record by matching a primary key or a
+ records from the database. The simplest is finding one record by matching a primary key or a
composite key (primary keys that consists of multiple columns).
See the <com:DocLink ClassPath="System.Data.ActiveRecord.TActiveRecord" /> for
more details.
@@ -317,12 +317,12 @@ $criteria->Offset = 20;
</com:TTextHighlighter>
<div class="note"><b class="note">Note:</b>
-For MSSQL and when <tt>Limit</tt> and <tt>Offset</tt> are positive integer values. The
-actual query to be executed is modified by the
-<com:DocLink ClassPath="System.Data.ActiveRecord.Common.Mssql.TMssqlCommandBuilder"
+For MSSQL and when <tt>Limit</tt> and <tt>Offset</tt> are positive integer values. The
+actual query to be executed is modified by the
+<com:DocLink ClassPath="System.Data.ActiveRecord.Common.Mssql.TMssqlCommandBuilder"
Text="TMssqlCommandBuilder"
/>
-class according to
+class according to
<a href="http://troels.arvin.dk/db/rdbms/#select-limit-offset">http://troels.arvin.dk/db/rdbms/</a>
to emulate the <tt>Limit</tt> and <tt>Offset</tt> conditions.
</div>
@@ -353,11 +353,11 @@ $finder->find('Username = ? AND Password = ?', $name, $pass);
$finder->findAllByAge($age);
$finder->findAll('Age = ?', $age);
</com:TTextHighlighter>
-
+
<div class="tip"><b class="note">Tip:</b>
You may also use a combination of <tt>AND</tt> and <tt>OR</tt> as a condition in the dynamic methods.
</div>
-
+
<h3 id="138060"><tt>findBySql()</tt> and <tt>findAllBySql()</tt></h3>
<p id="690497" class="block-content">Finds records using full SQL where <tt>findBySql()</tt>
return an Active Record and <tt>findAllBySql()</tt>returns an array of record objects.
@@ -391,16 +391,16 @@ $user2 = new UserRecord($data); //create by passing some existing data
$user2->save(); //insert a new record
</com:TTextHighlighter>
<div class="tip"><b class="note">Tip:</b>
-The objects are update with the primary key of those the tables that contains
+The objects are update with the primary key of those the tables that contains
definitions that automatically creates a primary key for the newly insert records.
For example, if you insert a new record into a MySQL table that has columns
-defined with "autoincrement", the Active Record objects will be updated with the new
+defined with "autoincrement", the Active Record objects will be updated with the new
incremented value.</div>
<p id="690500" class="block-content">
-To update a record in the database, just change one or more properties of
+To update a record in the database, just change one or more properties of
the Active Record object that has been loaded from the database and then
-call the <tt>save()</tt> method.
+call the <tt>save()</tt> method.
<com:TTextHighlighter Language="php" CssClass="source block-content" id="code_690162">
$user = UserRecord::finder()->findByName('admin');
@@ -416,9 +416,9 @@ Active Record objects have a simple life-cycle illustrated in the following diag
<p id="690501" class="block-content">
We see that new TActiveRecord objects are created by either using one of the <tt>find*()</tt>
methods or using creating a new instance by using PHP's <tt>new</tt> keyword. Objects
-created by a <tt>find*()</tt> method starts with <tt>clean</tt> state. New instance of
+created by a <tt>find*()</tt> method starts with <tt>clean</tt> state. New instance of
TActiveRecord created other than by a <tt>find*()</tt> method starts with <tt>new</tt> state.
-Whenever you
+Whenever you
call the <tt>save()</tt> method on the TActiveRecord object, the object enters the <tt>clean</tt>
state. Objects in the <tt>clean</tt> becomes <tt>dirty</tt> whenever one of more of its
internal states are changed. Calling the <tt>delete()</tt> method on the object
@@ -429,8 +429,8 @@ ends the object life-cycle, no further actions can be performed on the object.
<p id="690502" class="block-content">
To delete an existing record that is already loaded, just call the <tt>delete()</tt> method.
You can also delete records in the database by primary keys without
- loading any records using the <tt>deleteByPk()</tt> method (and equivalently the <tt>deleteAllByPks()</tt> method).
- For example, to delete one or records with tables using one or more primary keys.
+ loading any records using the <tt>deleteByPk()</tt> method (and equivalently the <tt>deleteAllByPks()</tt> method).
+ For example, to delete one or several records with tables using one or more primary keys.
</p>
<com:TTextHighlighter Language="php" CssClass="source block-content" id="code_690163">
$finder->deleteByPk($primaryKey); //delete 1 record
@@ -491,20 +491,20 @@ catch(Exception $e) // an exception is raised if a query fails
The TActiveRecord offers two events, <tt>OnCreateCommand</tt> and <tt>OnExecuteCommand</tt>.
</p>
-<p id="710014" class="block-content">The <tt>OnCreateCommand</tt> event is raised when a command is prepared and
+<p id="710014" class="block-content">The <tt>OnCreateCommand</tt> event is raised when a command is prepared and
parameter binding is completed. The parameter object is <tt>TDataGatewayEventParameter</tt> of which the
<tt>Command</tt> property can be inspected to obtain the SQL query to be executed.
</p>
<p id="710015" class="block-content">
-The <tt>OnExecuteCommand</tt> event is raised when a command is executed and the
-result from the database was returned. The parameter object is <tt>TDataGatewayResultEventParameter</tt>
-of which the <tt>Result</tt> property contains the data return from the database.
+The <tt>OnExecuteCommand</tt> event is raised when a command is executed and the
+result from the database was returned. The parameter object is <tt>TDataGatewayResultEventParameter</tt>
+of which the <tt>Result</tt> property contains the data return from the database.
The data returned can be changed by setting the <tt>Result</tt> property.
</p>
<h3 id="142016">Logging Example</h3>
-<p id="710016" class="block-content">Using the <tt>OnExecuteCommand</tt> we can attach an event handler to log
+<p id="710016" class="block-content">Using the <tt>OnExecuteCommand</tt> we can attach an event handler to log
the entire SQL query executed for a given TActiveRecord class or instance. For example, we define
a base class and override either the <tt>getDbConnection()</tt> or the constructor.
</p>
@@ -534,7 +534,7 @@ function logger($sender,$param)
}
TActiveRecord::finder('MyRecord')->OnExecuteCommand[] = 'logger';
$obj->OnExecuteCommand[] = array($logger, 'log'); //any valid PHP callback.
-</com:TTextHighlighter>
+</com:TTextHighlighter>
<h1 id="ar_relations">Active Record Relationships</h1>
<com:SinceVersion Version="3.1rc1" />
@@ -545,26 +545,26 @@ underlying database must support foreign key constraints (e.g. MySQL using InnoD
</p>
<p id="710017" class="block-content">
-In the following sections we shall consider the following table relationships between
+In the following sections we will consider the following table relationships between
<tt>Teams</tt>, <tt>Players</tt>, <tt>Skills</tt> and <tt>Profiles</tt>.
</p>
<img src=<%~ ar_relations.png %> class="figure" />
<p id="710018" class="block-content">The goal is to obtain object models that represent to some degree the entity
-relationships in the above figure.
+relationships in the above figure.
</p>
<img src=<%~ ar_objects.png %> class="figure" />
<p class="block-content">
-There is a mismatch between relationships with objects and table relationships.
-First there's a difference in representation. Objects handle links by storing references
-that are held by the runtime memory-managed environment. Relational databases handle
-links by forming a key into another table. Second, objects can easily use collections
-to handle multiple references from a single field, while normalization forces
-all entity relation links to be single valued. This leads to reversals of the data
-structure between objects and tables. The approach taken in the Prado Active Record
+There is a mismatch between relationships with objects and table relationships.
+First there's a difference in representation. Objects handle links by storing references
+that are held by the runtime memory-managed environment. Relational databases handle
+links by forming a key into another table. Second, objects can easily use collections
+to handle multiple references from a single field, while normalization forces
+all entity relation links to be single valued. This leads to reversals of the data
+structure between objects and tables. The approach taken in the Prado Active Record
design is to use the table foreign key constraints to derive object relationships. This implies
that the underlying database must support foreign key constraints.
</p>
@@ -589,9 +589,9 @@ CREATE TABLE bar
<h2 id="142012">Foreign Key Mapping</h2>
<p class="block-content">The entity relationship between the <tt>Teams</tt> and <tt>Players</tt> table is what is known
-as an 1-M relationship. That is, one Team may contain 0 or more Players. In terms of
-object relationships, we say that a <tt>TeamRecord</tt> object <b>has many</b> <tt>PlayerRecord</tt> objects.
-(Notice the reversal of the reversal of the direction of relationships between tables and objects.)
+as an 1-M relationship. That is, one Team may contain 0 or more Players. In terms of
+object relationships, we say that a <tt>TeamRecord</tt> object <b>has many</b> <tt>PlayerRecord</tt> objects.
+(Notice the reversal of the direction of relationships between tables and objects.)
<p id="710019" class="block-content">
<h3 id="142017">Has Many Relationship</h3>
<p id="710020" class="block-content">
@@ -603,7 +603,7 @@ class TeamRecord extends TActiveRecord
const TABLE='Teams';
public $name;
public $location;
-
+
public $players=array();
//define the $player member having has many relationship with PlayerRecord
@@ -644,7 +644,7 @@ have other relationships that corresponds to other tables (including the <tt>Pla
</div>
<p id="710023" class="block-content">The "has many" relationship is not fetched automatically when you use any of the Active Record finder methods.
-You will need to explicitly fetch the related objects as follows. In the code below, both lines
+You will need to explicitly fetch the related objects as follows. In the code below, both lines
are equivalent and the method names are case insensitive.
</p>
<com:TTextHighlighter Language="php" CssClass="source block-content">
@@ -661,8 +661,8 @@ arguments as other finder methods of TActiveRecord, e.g. <tt>with_players('age =
<div class="note"><b class="note">Note:</b>
It is essential to understand that the related objects are fetched using additional
queries. The first query fetches the source object, e.g. the <tt>TeamRecord</tt> in the above example code.
-A second query is used to fetch the corresponding related <tt>PlayerRecord</tt> objects.
-The usage of the two query is similar to a single query using Left-Outer join with the
+A second query is used to fetch the corresponding related <tt>PlayerRecord</tt> objects.
+The usage of the two query is similar to a single query using Left-Outer join with the
exception that null results on the right table
are not returned. The consequence of using two or more queries is that the aggregates
and other join conditions are not feasible using Active Records. For queries outside the
@@ -673,7 +673,7 @@ scope of Active Record the <a href="?page=Database.SqlMap">SqlMap Data Mapper</a
<p id="710025" class="block-content">The "has many" relationship in the above section defines a collection of foreign
objects. In particular, we have that a <tt>TeamRecord</tt> has many (zero or more)
<tt>PlayerRecord</tt> objects. We can also add a back pointer by adding a property
-in the <tt>PlayerRecord</tt> class that links back to the <tt>TeamRecord</tt> object,
+in the <tt>PlayerRecord</tt> class that links back to the <tt>TeamRecord</tt> object,
effectively making the association bidirectional.
We say that the <tt>$team</tt> property in <tt>PlayerRecord</tt> class <tt>belongs to</tt> a <tt>TeamRecord</tt> object.
The following code defines the complete <tt>PlayerRecord</tt> class with 3 relationships.
@@ -705,11 +705,11 @@ class PlayerRecord extends TActiveRecord
</com:TTextHighlighter>
<p id="710026" class="block-content">
The static <tt>$RELATIONS</tt> property of <tt>PlayerRecord</tt> defines that the
-property <tt>$team</tt> <b>belongs to</b> a <tt>TeamRecord</tt>.
+property <tt>$team</tt> <b>belongs to</b> a <tt>TeamRecord</tt>.
The <tt>$RELATIONS</tt> array also defines two other relationships that we
-shall examine in later sections below.
+shall examine in later sections below.
In <tt>array(self::BELONGS_TO, 'TeamRecord')</tt>, the first element defines the
-relationship type, in this case <strong><tt>self::BELONGS_TO</tt></strong> and
+relationship type, in this case <strong><tt>self::BELONGS_TO</tt></strong> and
the second element is a string <tt>'TeamRecord'</tt> that corresponds to the
class name of the <tt>TeamRecord</tt> class.
A player object with the corresponding team object may be fetched as follows.
@@ -732,7 +732,7 @@ example demonstrates.
<com:TTextHighlighter Language="php" CssClass="source block-content">
$players = PlayerRecord::finder()->with_team()->with_skills()->findAll();
</com:TTextHighlighter>
-Each <tt>with_xxx()</tt> method will execute an additional SQL query. Every
+Each <tt>with_xxx()</tt> method will execute an additional SQL query. Every
<tt>with_xxx()</tt> accepts arguments similar to those in the <tt>findAll()</tt> method and is only
applied to that particular relationship query.
</div>
@@ -765,7 +765,7 @@ the <tt>Profiles</tt> table has a foreign key constraint on the column <tt>playe
that relates to the <tt>Players</tt> table's <tt>player_id</tt> column. Thus, the <tt>ProfileRecord</tt>
object has a property (<tt>$player</tt>) that <b>belongs to</b> a <tt>PlayerRecord</tt> object.
Similarly, the <tt>Players</tt> table has a foreign key constraint on the column <tt>team_name</tt> that relates to the
-<tt>Teams</tt> table's <tt>name</tt> column.
+<tt>Teams</tt> table's <tt>name</tt> column.
Thus, the <tt>PlayerRecord</tt> object has a property (<tt>$team</tt>) that <b>belongs to</b> a
<tt>TeamRecord</tt> object.
</p>
@@ -804,32 +804,32 @@ class Category extends TActiveRecord
<h2 id="142013">Association Table Mapping</h2>
<p id="710032" class="block-content">
-Objects can handle multivalued fields quite easily by using collections as field values.
-Relational databases don't have this feature and are constrained to single-valued fields only.
-When you're mapping a one-to-many association you can handle this using <b>has many</b> relationships,
-essentially using a foreign key for the single-valued end of the association.
-But a many-to-many association can't do this because there is no single-valued end to
+Objects can handle multivalued fields quite easily by using collections as field values.
+Relational databases don't have this feature and are constrained to single-valued fields only.
+When you're mapping a one-to-many association you can handle this using <b>has many</b> relationships,
+essentially using a foreign key for the single-valued end of the association.
+But a many-to-many association can't do this because there is no single-valued end to
hold the foreign key.
</p>
<p id="710033" class="block-content">
-The answer is the classic resolution that's been used by relational data people
-for decades: create an extra table (an association table) to record the relationship.
-The basic idea is using an association table to store the association. This table
-has only the foreign key IDs for the two tables that are linked together, it has one
+The answer is the classic resolution that's been used by relational data people
+for decades: create an extra table (an association table) to record the relationship.
+The basic idea is using an association table to store the association. This table
+has only the foreign key IDs for the two tables that are linked together, it has one
row for each pair of associated objects.
</p>
<p id="710034" class="block-content">
-The association table has no corresponding in-memory object and its primary key is the
+The association table has no corresponding in-memory object and its primary key is the
compound of the two primary keys of the tables that are associated.
-In simple terms, to load data from the association table you perform two queries (in general, it may also be achieved using one query consisting of joins).
-Consider loading the <tt>SkillRecord</tt> collection for a list <tt>PlayerRecord</tt> objects.
-In this case, you do queries in two stages.
-The first stage queries the <tt>Players</tt> table to find all the rows of the players you want.
-The second stage finds the <tt>SkillRecord</tt> object for the related player ID for each row
+In simple terms, to load data from the association table you perform two queries (in general, it may also be achieved using one query consisting of joins).
+Consider loading the <tt>SkillRecord</tt> collection for a list <tt>PlayerRecord</tt> objects.
+In this case, you do queries in two stages.
+The first stage queries the <tt>Players</tt> table to find all the rows of the players you want.
+The second stage finds the <tt>SkillRecord</tt> object for the related player ID for each row
in the <tt>Player_Skills</tt> association table using an inner join.
</p>
-<p id="710035" class="block-content">The Prado Active Record design implements the two stage approach. For the
+<p id="710035" class="block-content">The Prado Active Record design implements the two stage approach. For the
<tt>Players</tt>-<tt>Skills</tt> M-N (many-to-many) entity relationship, we need
to define a <b>has many</b> relationship in the <tt>PlayerRecord</tt> class and
in addition define a <b>has many</b> relationship in the <tt>SkillRecord</tt> class as well.
@@ -866,7 +866,7 @@ In <tt>array(self::HAS_MANY, 'PlayerRecord', 'Player_Skills')</tt>, the first el
relationship type, in this case <strong><tt>self::HAS_MANY</tt></strong>,
the second element is a string <tt>'PlayerRecord'</tt> that corresponds to the
class name of the <tt>PlayerRecord</tt> class, and the third element is the name
-of the association table name.
+of the association table name.
</p>
<p id="710037" class="block-content">
A list of player objects with the corresponding collection of skill objects may be fetched as follows.
@@ -889,22 +889,22 @@ item via the <tt>related_items</tt> association table. The syntax in the followi
example is valid for a PostgreSQL database. For other database, consult their respective documentation for
defining the foreign key constraints.
<com:TTextHighlighter Language="sql" CssClass="source block-content">
-CREATE TABLE items
+CREATE TABLE items
(
- "item_id" SERIAL,
+ "item_id" SERIAL,
"name" VARCHAR(128) NOT NULL,
PRIMARY KEY("item_id")
);
-CREATE TABLE "related_items"
+CREATE TABLE "related_items"
(
- "item_id" INTEGER NOT NULL,
- "related_item_id" INTEGER NOT NULL,
- CONSTRAINT "related_items_pkey" PRIMARY KEY("item_id", "related_item_id"),
+ "item_id" INTEGER NOT NULL,
+ "related_item_id" INTEGER NOT NULL,
+ CONSTRAINT "related_items_pkey" PRIMARY KEY("item_id", "related_item_id"),
CONSTRAINT "related_items_item_id_fkey" FOREIGN KEY ("item_id")
REFERENCES "items"("item_id")
ON DELETE CASCADE
ON UPDATE NO ACTION
- NOT DEFERRABLE,
+ NOT DEFERRABLE,
CONSTRAINT "related_items_related_item_id_fkey" FOREIGN KEY ("related_item_id")
REFERENCES "items"("item_id")
ON DELETE CASCADE
@@ -916,7 +916,7 @@ CREATE TABLE "related_items"
<p id="710040" class="block-content">The association table name in third element of the relationship array may
contain the foreign table column names. The columns defined in the association
table must also be defined in the record class (e.g. the <tt>$related_item_id</tt> property
-corresponds to the <tt>related_item_id</tt> column in the <tt>related_items</tt> table).
+corresponds to the <tt>related_item_id</tt> column in the <tt>related_items</tt> table).
</p>
<com:TTextHighlighter Language="php" CssClass="source block-content">
class Item extends TActiveRecord
@@ -926,20 +926,20 @@ class Item extends TActiveRecord
public $details;
//additional foreign item id defined in the association table
- public $related_item_id;
+ public $related_item_id;
public $related_items=array();
protected static $RELATIONS=array
(
- 'related_items' => array(self::HAS_MANY,
+ 'related_items' => array(self::HAS_MANY,
'Item', 'related_items.related_item_id'),
);
}
</com:TTextHighlighter>
<div class="tip"><b class="note">Tip:</b>
-Compound keys in the foreign table can
+Compound keys in the foreign table can
be specified as comma separated values between brackets. E.g.
-<tt>'related_items.(id1,id2)'</tt>.
+<tt>'related_items.(id1,id2)'</tt>.
</div>
<h2 id="142014">Adding/Removing/Updating Related Objects</h2>
@@ -959,7 +959,7 @@ $team->save();
</com:TTextHighlighter>
<p id="710042" class="block-content">
Since the <tt>TeamRecord</tt> class contains a <b>has many</b> relationship with the <tt>PlayerRecord</tt>,
-then saving a <tt>TeamRecord</tt> object will also update the corresponding foreign objects in <tt>$players</tt> array.
+then saving a <tt>TeamRecord</tt> object will also update the corresponding foreign objects in <tt>$players</tt> array.
That is, the objects in <tt>$players</tt> are inserted/updated in the database and the
<tt>$team_name</tt> property of those objects will contain the foreign key value that corresponds to the <tt>$team</tt> object's primary key value.
</p>
@@ -969,7 +969,7 @@ the object's <tt>delete()</tt> method. You may setup the database table's foreig
when deleting a particular data in the database it will delete the referenced data as well (it may also be achieved using database
triggers). E.g. such as having a "<tt>ON DELETE CASCADE</tt>" constraint.
Deleting foreign objects by either setting the property value to null or removing the object from an array will <b>NOT</b>
-remove the corresponding data in the database.
+remove the corresponding data in the database.
</p>
<p id="710044" class="block-content">To remove associations for the many-to-many relationships via an association table, an Active Record
@@ -983,7 +983,7 @@ PlayerSkillAssocation::finder()->deleteByPk(array('fk1','fk2'));
<h2 id="142015">Lazy Loading Related Objects</h2>
<p id="710045" class="block-content">Using the <tt>with_xxx()</tt> methods will load the relationship record on demand. Retrieving the
-related record using lazy loading (that is, only when those related objects are accessed) can be
+related record using lazy loading (that is, only when those related objects are accessed) can be
achieved by using a feature of the <tt>TComponent</tt> that provides accessor methods. In particular,
we define a pair of getter and setter methods where the getter method will retrieve the relationship
conditionally. The following example illustrates that the <tt>PlayerRecord</tt> can retrieve its
@@ -995,7 +995,7 @@ class PlayerRecord extends BaseFkRecord
//... other properties and methods as before
private $_skills; //change to private and default as null
-
+
public function getSkills()
{
if($this->_skills===null && $this->player_id !==null)
@@ -1018,12 +1018,12 @@ class PlayerRecord extends BaseFkRecord
}
}
</com:TTextHighlighter>
-<p id="710046" class="block-content">We first need to change the <tt>$skills=array()</tt> declaration to a private property
+<p id="710046" class="block-content">We first need to change the <tt>$skills=array()</tt> declaration to a private property
<tt>$_skills</tt> (notice the underscore) and set it to null instead. This allows us
-to define the <tt>skills</tt> property using getter/setter methods
+to define the <tt>skills</tt> property using getter/setter methods
(see <a href="?page=Fundamentals.Components">Components</a> for details). The <tt>getSkills()</tt>
getter method for the <tt>skills</tt> property will lazy load the corresponding skills foreign record
-when it is used as follows. Notice that we only do a lazy load when its <tt>$player_id</tt> is
+when it is used as follows. Notice that we only do a lazy load when its <tt>$player_id</tt> is
not null (that is, when the record is already fetched from the database or player id was already set).
</p>
<com:TTextHighlighter Language="php" CssClass="source block-content">
@@ -1036,7 +1036,7 @@ $player->skills[] = new SkillRecord(); //add skill
<p id="710047" class="block-content">The <tt>setSkills()</tt> ensures that the <tt>skills</tt> property will always be a TList.
Using a TList allows us to set the elements of the <tt>skills</tt> property as if they were
arrays. E.g. <tt>$player->skills[] = new SkillRecord()</tt>. If <tt>array</tt> was used, a PHP error
-will be thrown.
+will be thrown.
</p>
<h2 id="138054">References</h2>
diff --git a/demos/quickstart/protected/pages/Database/SqlMap.page b/demos/quickstart/protected/pages/Database/SqlMap.page
index 2e3aed16..40e8ba20 100644
--- a/demos/quickstart/protected/pages/Database/SqlMap.page
+++ b/demos/quickstart/protected/pages/Database/SqlMap.page
@@ -3,7 +3,7 @@
<h1 id="140062">Data Mapper</h1>
<com:SinceVersion Version="3.1a" />
-<p id="700505" class="block-content">Data Mappers moves data between objects and a database while keeping them
+<p id="700505" class="block-content">Data Mappers moves data between objects and a database while keeping them
independent of each other and the mapper itself. If you started with
<a href="?page=Database.ActiveRecord">Active Records</a>, you may eventually
faced with more complex business
@@ -13,11 +13,11 @@
that is, the object schema and the relational schema don't match up.
</p>
-<p id="700506" class="block-content">The Data Mapper separates the in-memory objects from the database. Its responsibility
- is to transfer data between the two and also to isolate them from each other.
- With Data Mapper the in-memory objects needn't know even that there's a database
+<p id="700506" class="block-content">The Data Mapper separates the in-memory objects from the database. Its responsibility
+ is to transfer data between the two and also to isolate them from each other.
+ With Data Mapper the in-memory objects needn't know even that there's a database
present; they need no SQL interface code, and certainly no knowledge of the
- database schema. (The database schema is always ignorant of the objects that use it.)
+ database schema. (The database schema is always ignorant of the objects that use it.)
</p>
<h2 id="140063">When to Use It</h2>
@@ -28,46 +28,46 @@
what the database structure is, because all the correspondence is done by the mappers.
</p>
-<p id="700508" class="block-content">This helps you in the code because you can understand and work with the domain objects
- without having to understand how they're stored in the database. You can modify the
+<p id="700508" class="block-content">This helps you in the code because you can understand and work with the domain objects
+ without having to understand how they're stored in the database. You can modify the
business models or the database without having to alter either. With complicated
mappings, particularly those involving <b>existing databases</b>, this is very valuable.
</p>
-<p id="700509" class="block-content">The price, of course, is the extra layer that you don't get with
- <a href="?page=Database.ActiveRecord">Active Record</a>,
- so the test for using these patterns is the complexity of the business logic.
- If you have fairly simple business logic, an <a href="?page=Database.ActiveRecord">Active Record</a>
- will probably work.
+<p id="700509" class="block-content">The price, of course, is the extra layer that you don't get with
+ <a href="?page=Database.ActiveRecord">Active Record</a>,
+ so the test for using these patterns is the complexity of the business logic.
+ If you have fairly simple business logic, an <a href="?page=Database.ActiveRecord">Active Record</a>
+ will probably work.
For more complicated logic a Data Mapper may be more suitable.
</p>
<h2 id="140064">SqlMap Data Mapper</h2>
-<p id="700510" class="block-content">The SqlMap DataMapper framework makes it easier to use a database with a PHP application.
- SqlMap DataMapper couples objects with stored procedures or SQL statements using
- a XML descriptor. Simplicity is the biggest advantage of the SqlMap DataMapper over
- object relational mapping tools. To use SqlMap DataMapper you rely on your own objects,
- XML, and SQL. There is little to learn that you don't already know.
+<p id="700510" class="block-content">The SqlMap DataMapper framework makes it easier to use a database with a PHP application.
+ SqlMap DataMapper couples objects with stored procedures or SQL statements using
+ a XML descriptor. Simplicity is the biggest advantage of the SqlMap DataMapper over
+ object relational mapping tools. To use SqlMap DataMapper you rely on your own objects,
+ XML, and SQL. There is little to learn that you don't already know.
With SqlMap DataMapper you have the full power of both SQL and stored procedures at
your fingertip
</p>
<p id="700511" class="block-content">
<img src=<%~ diagram.png %> alt="SqlMap Data Mapper Overview" id="fig:sqlmap.png" class="figure"/>
-
- Here's a high level description of the work flow illustrated in the figure abov.
+
+ Here's a high level description of the work flow illustrated in the figure above.
Provide a parameter, either as an object or a primitive type. The parameter can be
- used to set runtime values in your SQL statement or stored procedure. If a runtime value
+ used to set runtime values in your SQL statement or stored procedure. If a runtime value
is not needed, the parameter can be omitted.
</p>
-<p id="700512" class="block-content">Execute the mapping by passing the parameter and the name you gave the statement or
+<p id="700512" class="block-content">Execute the mapping by passing the parameter and the name you gave the statement or
procedure in your XML descriptor. This step is where the magic happens. The framework
- will prepare the SQL statement or stored procedure, set any runtime values using your
+ will prepare the SQL statement or stored procedure, set any runtime values using your
parameter, execute the procedure or statement, and return the result.
</p>
<p id="700513" class="block-content">In the case of an update, the number of rows affected is returned. In the case of a
- query, a single object, or a collection of objects is returned. Like the parameter,
+ query, a single object, or a collection of objects is returned. Like the parameter,
the result object, or collection of objects, can be a plain-old object or a primitive PHP type.
</p>
@@ -82,8 +82,8 @@ $dsn = 'pgsql:host=localhost;dbname=test'; //Postgres SQL
$conn = new TDbConnection($dsn, 'dbuser','dbpass');
$manager = new TSqlMapManager($conn);
$manager->configureXml('my-sqlmap.xml');
-$sqlmap = $manager->getSqlMapGateway();
-</com:TTextHighlighter>
+$sqlmap = $manager->getSqlMapGateway();
+</com:TTextHighlighter>
</p>
<p id="700515" class="block-content">
@@ -96,31 +96,31 @@ $sqlmap = $manager->getSqlMapGateway();
<p id="700516" class="block-content">
SqlMap database connection can also be configured using a <tt>&lt;module&gt;</tt>
- tag in the <a href="?page=Configurations.AppConfig">application.xml</a>
+ tag in the <a href="?page=Configurations.AppConfig">application.xml</a>
or <a href="?page=Configurations.PageConfig">config.xml</a> as follows.
<com:TTextHighlighter Language="xml" CssClass="source block-content" id="code_700167">
<modules>
- <module id="my-sqlmap" class="System.Data.SqlMap.TSqlMapConfig"
+ <module id="my-sqlmap" class="System.Data.SqlMap.TSqlMapConfig"
EnableCache="true" ConfigFile="my-sqlmap.xml" >
<database ConnectionString="pgsql:host=localhost;dbname=test"
Username="dbuser" Password="dbpass" />
</module>
-</modules>
-</com:TTextHighlighter>
+</modules>
+</com:TTextHighlighter>
</p>
<p id="700517" class="block-content">
The <tt>ConfigFile</tt> attribute should point to a SqlMap configuration file
- (to be detailed later) either using absolute path, relative path or the
+ (to be detailed later) either using absolute path, relative path or the
Prado's namespace dot notation path (must omit the ".xml" extension).
-
+
<div class="tip"><b class="note">Tip:</b>
The <tt>EnableCache</tt> attribute when set to "true" will cache the
parsed configuration. You must clear or disable the cache if you
- make chanages your configuration file.
+ make changes to your configuration file.
A <a href="?page=Advanced.Performance#6402">cache
module</a> must also be defined for the cache to function.
- </div>
+ </div>
</p>
<p id="700518" class="block-content">To obtain the SqlMap gateway interface from the &lt;module&gt; configuration, simply
@@ -140,8 +140,8 @@ class MyPage extends TPage
<h2 id="140066">A quick example</h2>
<p id="700519" class="block-content">Let us
- consider the following "users" table that contains two columns named "username" and "email",
- where "username" is also the primary key.
+ consider the following "users" table that contains two columns named "username" and "email",
+ where "username" is also the primary key.
<com:TTextHighlighter Language="sql" CssClass="source block-content" id="code_700169">
CREATE TABLE users
(
@@ -178,7 +178,7 @@ class User
attribute will be used as the identifier for the query. The <tt>resultClass</tt>
attribute value is the name of the class the the objects to be returned.
We can now query the objects as follows:
-
+
<com:TTextHighlighter Language="php" CssClass="source block-content" id="code_700172">
//assume that $sqlmap is an TSqlMapGateway instance
$userList = $sqlmap->queryForList("SelectUsers");
@@ -189,7 +189,7 @@ $user = $sqlmap->queryForObject("SelectUsers");
</p>
<p id="700523" class="block-content">The above example shows demonstrates only a fraction of the capabilities
- of the SqlMap Data Mapper. Further details can be found in the
+ of the SqlMap Data Mapper. Further details can be found in the
<a href="http://www.pradosoft.com/demo/sqlamp/">SqlMap Manual</a>.
</p>
@@ -197,12 +197,12 @@ $user = $sqlmap->queryForObject("SelectUsers");
<p id="700524" class="block-content">The above example may seem trival and it also seems that there is
alot work just to retrieve some data. However, notice that the <tt>User</tt>
class is totally unware of been stored in the database, and the database is
- unware of the <tt>User</tt> class.
+ unware of the <tt>User</tt> class.
</p>
<p id="700525" class="block-content">
One of advantages of SqlMap is the
ability to map complex object relationship, collections from an existing
- database. On the other hand, <a href="?page=Database.ActiveRecord">Active Record</a>
+ database. On the other hand, <a href="?page=Database.ActiveRecord">Active Record</a>
provide a very simple way
to interact with the underlying database but unable to do more complicated
relationship or collections. A good compromise is to use SqlMap to retrieve
@@ -214,11 +214,11 @@ $user = $sqlmap->queryForObject("SelectUsers");
<com:TTextHighlighter Language="php" CssClass="source block-content" id="code_700173">
class UserRecord extends TActiveRecord
{
- const TABLE='users'; //table name
+ const TABLE='users'; //table name
public $username; //the column named "username" in the "users" table
public $email;
-
+
/**
* @return TActiveRecord active record finder instance
*/
@@ -245,7 +245,7 @@ class UserRecord extends TActiveRecord
<p id="700528" class="block-content">The PHP code for retrieving the users remains the same, but SqlMap
returns Active Records instead, and we can take advantage of the Active Record methods.
-
+
<com:TTextHighlighter Language="php" CssClass="source block-content" id="code_700175">
//assume that $sqlmap is an TSqlMapGateway instance
$user = $sqlmap->queryForObject("SelectUsers");
@@ -259,7 +259,7 @@ $user->save(); //save it using Active Record
<ul id="u1" class="block-content">
<li>Fowler et. al. <i>Patterns of Enterprise Application Architecture</i>,
Addison Wesley, 2002.</li>
- <li>iBatis Team. <i>iBatis Data Mapper</i>,
+ <li>iBatis Team. <i>iBatis Data Mapper</i>,
<a href="http://ibatis.apache.org">http://ibatis.apache.org</a>.</li>
</ul>