DataStore · 4D Documentation

A Datastore is the interface object provided by ORDA to reference and access a database. Datastore objects are returned by the following commands:

ds: a shortcut to the main datastore
Open datastore: to open any remote datastore

Summary


.cancelTransaction() cancels the transaction
*.dataclassName* : 4D.DataClass contains a description of the dataclass
.encryptionStatus(): Object returns an object providing the encryption status for the current data file
.getInfo(): Object returns an object providing information about the datastore
.getRequestLog() : Collection returns the ORDA requests logged in memory on the client side
.makeSelectionsAlterable() sets all entity selections as alterable by default in the current application datastores
.provideDataKey( curPassPhrase : Text ) : Object .provideDataKey( curDataKey : Object ) : Object allows providing a data encryption key for the current data file of the datastore and detects if the key matches the encrypted data
.setAdminProtection( status : Boolean ) allows disabling any data access on the web admin port, including for the Data Explorer in `WebAdmin` sessions
.startRequestLog() .startRequestLog( file : 4D.File ) .startRequestLog( reqNum : Integer ) starts the logging of ORDA requests on the client side
.startTransaction() starts a transaction in the current process on the database matching the datastore to which it applies
.stopRequestLog() stops any logging of ORDA requests on the client side
.validateTransaction() accepts the transaction

ds

History

Version	Changes
v18	Support of localID parameter
v17	Added

ds { ( localID : Text ) } : cs.DataStore

Parameter	Type		Description
localID	Text	->	Local ID of the remote datastore to return
Result	cs.DataStore	<-	Reference to the datastore

Description

The ds command returns a reference to the datastore matching the current 4D database or the database designated by localID.

If you omit the localID parameter (or pass an empty string ""), the command returns a reference to the datastore matching the local 4D database (or the 4D Server database in case of opening a remote database on 4D Server). The datastore is opened automatically and available directly through ds.

You can also get a reference on an open remote datastore by passing its local id in the localID parameter. The datastore must have been previously opened with the Open datastore command by the current database (host or component). The local id is defined when using this command.

The scope of the local id is the database where the datastore has been opened.

If no localID datastore is found, the command returns Null.

Using ds requires that the target database is compliant with ORDA, as specified in the ORDA prerequisites section. The following rules are applied:

A datastore only references tables with a single primary key. Tables without a primary key or with composite primary keys are not referenced.
BLOB type attributes are not managed in the datastore.

Example 1

Using the main datastore on the 4D database:

 $result:=ds.Employee.query("firstName = :1";"S@")

Example 2

 var $connectTo; $firstFrench; $firstForeign : Object

 var $frenchStudents; $foreignStudents : cs.DataStore

 $connectTo:=New object("type";"4D Server";"hostname";"192.168.18.11:8044")
 $frenchStudents:=Open datastore($connectTo;"french")

 $connectTo.hostname:="192.168.18.11:8050"
 $foreignStudents:=Open datastore($connectTo;"foreign")
  //...
  //...
 $firstFrench:=getFirst("french";"Students")
 $firstForeign:=getFirst("foreign";"Students")

  //getFirst method
  //getFirst(localID;dataclass) -> entity
 #DECLARE( $localId : Text; $dataClassName : Text ) -> $entity : 4D.Entity

 $0:=ds($localId)[$dataClassName].all().first()

Open datastore

History

Version	Changes
v18	Added

Open datastore( connectionInfo : Object ; localID : Text ) : cs.DataStore

Parameter	Type		Description
connectionInfo	Object	->	Connection properties used to reach the remote datastore
localID	Text	->	Id to assign to the opened datastore on the local application (mandatory)
Result	cs.DataStore	<-	Datastore object

Description

The Open datastore command connects the application to the 4D database identified by the connectionInfo parameter and returns a matching cs.DataStore object associated with the localID local alias.

The connectionInfo 4D database must be available as a remote datastore, i.e.:

its web server must be launched with http and/or https enabled,
its Expose as REST server option must be checked,
at least one client license is available.

If no matching database is found, Open datastore returns Null.

localID is a local alias for the session opened on remote datastore. If localID already exists on the application, it is used. Otherwise, a new localID session is created when the datastore object is used.

Once the session is opened, the following statements become equivalent and return a reference on the same datastore object:

 $myds:=Open datastore(connectionInfo;"myLocalId")
 $myds2:=ds("myLocalId")
  //$myds and $myds2 are equivalent

Pass in connectionInfo an object describing the remote datastore you want to connect to. It can contain the following properties (all properties are optional except hostname):

Property	Type	Description
hostname	Text	Name or IP address of the remote database + ":" + port number (port number is mandatory)
user	Text	User name
password	Text	User password
idleTimeout	Longint	Inactivity session timeout (in minutes), after which the session is automatically closed by 4D. If omitted, default value is 60 (1h). The value cannot be < 60 (if a lower value is passed, the timeout is set to 60). For more information, see Closing sessions.
tls	Boolean	Use secured connection(*). If omitted, false by default. Using a secured connection is recommended whenever possible.
type	Text	Must be "4D Server"

(*) If tls is true, the HTTPS protocol is used if:

HTTPS is enabled on the remote datastore
the given port is the right HTTPS port configured in the database settings
a valid certificate and private encryption key are installed in the database. Otherwise, error "1610 - A remote request to host xxx has failed" is raised

Example 1

Connection to a remote datastore without user / password:

 var $connectTo : Object
 var $remoteDS : cs.DataStore
 $connectTo:=New object("type";"4D Server";"hostname";"192.168.18.11:8044")
 $remoteDS:=Open datastore($connectTo;"students")
 ALERT("This remote datastore contains "+String($remoteDS.Students.all().length)+" students")

Example 2

Connection to a remote datastore with user / password / timeout / tls:

 var $connectTo : Object
 var $remoteDS : cs.DataStore
 $connectTo:=New object("type";"4D Server";"hostname";\"192.168.18.11:4443";\  
    "user";"marie";"password";$pwd;"idleTimeout";70;"tls";True)
 $remoteDS:=Open datastore($connectTo;"students")
 ALERT("This remote datastore contains "+String($remoteDS.Students.all().length)+" students")

Example 3

Working with several remote datastores:

 var $connectTo : Object
 var $frenchStudents; $foreignStudents : cs.DataStore
 $connectTo:=New object("hostname";"192.168.18.11:8044")
 $frenchStudents:=Open datastore($connectTo;"french")
 $connectTo.hostname:="192.168.18.11:8050"
 $foreignStudents:=Open datastore($connectTo;"foreign")
 ALERT("They are "+String($frenchStudents.Students.all().length)+" French students")
 ALERT("They are "+String($foreignStudents.Students.all().length)+" foreign students")

Error management

In case of error, the command returns Null. If the remote datastore cannot be reached (wrong address, web server not started, http and https not enabled...), error 1610 "A remote request to host XXX has failed" is raised. You can intercept this error with a method installed by ON ERR CALL.

.dataclassName

History

Version	Changes
v17	Added

.dataclassName : 4D.DataClass

Description

Each dataclass in a datastore is available as a property of the DataStore objectdata. The returned object contains a description of the dataclass.

Example

 var $emp : cs.Employee
 var $sel : cs.EmployeeSelection
 $emp:=ds.Employee //$emp contains the Employee dataclass
 $sel:=$emp.all() //gets an entity selection of all employees

  //you could also write directly:
 $sel:=ds.Employee.all()

.cancelTransaction()

History

Version	Changes
v18	Added

.cancelTransaction() | Parameter | Type | | Description | | --------- | ---- |::| ------------------------------- | | | | | Does not require any parameters |

Description

The .cancelTransaction() function cancels the transaction opened by the .startTransaction() function at the corresponding level in the current process for the specified datastore.

The .cancelTransaction() function cancels any changes made to the data during the transaction.

You can nest several transactions (sub-transactions). If the main transaction is cancelled, all of its sub-transactions are also cancelled, even if they were validated individually using the .validateTransaction() function.

Example

See example for the .startTransaction() function.

.encryptionStatus()

History

Version	Changes
v17 R5	Added

.encryptionStatus(): Object

Parameter	Type		Description
Result	Object	<-	Information about the encryption of the current datastore and of each table

Description

The .encryptionStatus() function returns an object providing the encryption status for the current data file (i.e., the data file of the ds datastore). The status for each table is also provided.

Use the Data file encryption status command to determine the encryption status of any other data file.

Returned value

The returned object contains the following properties:

Property			Type	Description
isEncrypted			Boolean	True if the data file is encrypted
keyProvided			Boolean	True if the encryption key matching the encrypted data file is provided(*).
tables			Object	Object containing as many properties as there are encryptable or encrypted tables.
	tableName		Object	Encryptable or Encrypted table
		name	Text	Name of the table
		num	Number	Table number
		isEncryptable	Boolean	True if the table is declared encryptable in the structure file
		isEncrypted	Boolean	True if the records of the table are encrypted in the data file

(*) The encryption key can be provided:

with the .provideDataKey() command,
at the root of a connected device before opening the datastore,
with the Discover data key command.

Example

You want to know the number of encrypted tables in the current data file:

 var $status : Object

 $status:=dataStore.encryptionStatus()

 If($status.isEncrypted) //the database is encrypted
    C_LONGINT($vcount)
    C_TEXT($tabName)
    For each($tabName;$status.tables)
       If($status.tables[$tabName].isEncrypted)
          $vcount:=$vcount+1
       End if
    End for each
    ALERT(String($vcount)+" encrypted table(s) in this datastore.")
 Else
    ALERT("This database is not encrypted.")
 End if

.getInfo()

History

Version	Changes
v17	Added

.getInfo(): Object

Parameter	Type		Description
Result	Object	<-	Datastore properties

Description

The .getInfo() function returns an object providing information about the datastore. This function is useful for setting up generic code.

Returned object

Property Type Description

type string "4D": main datastore, available through ds
"4D Server": remote datastore, open with Open datastore

networked boolean True: the datastore is reached through a network connection.
False: the datastore is not reached through a network connection (local database)

localID text ID of the datastore on the machine. Corresponds to the localId string given with the Open datastore command. Empty string ("") for main datastore.

connection

object

Object describing the remote datastore connection (not returned for main datastore). Available properties:

Property	Type	Description
hostname	text	IP address or name of the remote datastore + ":" + port number
tls	boolean	True if secured connection is used with the remote datastore
idleTimeout	number	Session inactivity timeout (in minutes)
user	text	User authenticated on the remote datastore

If the .getInfo() function is executed on a 4D Server or 4D single-user, networked is False.
If the .getInfo() function is executed on a remote 4D, networked is True

Example 1

 var $info : Object

 $info:=ds.getInfo() //Executed on 4D Server or 4D
  //{"type":"4D","networked":false,"localID":""}

 $info:=ds.getInfo() // Executed on 4D remote
  //{"type":"4D","networked":true,"localID":""}

Example 2

On a remote datastore:

  var $remoteDS : cs.DataStore
  var $info; $connectTo : Object

 $connectTo:=New object("hostname";"111.222.33.44:8044";"user";"marie";"password";"aaaa")
 $remoteDS:=Open datastore($connectTo;"students")
 $info:=$remoteDS.getInfo()

  //{"type":"4D Server",
  //"localID":"students",
  //"networked":true,
  //"connection":{hostname:"111.222.33.44:8044","tls":false,"idleTimeout":2880,"user":"marie"}}

.getRequestLog()

History

Version	Changes
v17 R6	Added

.getRequestLog() : Collection

Parameter	Type		Description
Result	Collection	<-	Collection of objects, where each object describes a request

Description

The .getRequestLog() function returns the ORDA requests logged in memory on the client side. The ORDA request logging must have previously been enabled using the .startRequestLog() function.

This function must be called on a remote 4D, otherwise it returns an empty collection. It is designed for debugging purposes in client/server configurations.

Returned value

Collection of stacked request objects. The most recent request has index 0.

For a description of the ORDA request log format, please refer to the ORDA client requests section.

Example

See Example 2 of .startRequestLog().

.isAdminProtected()

History

Version	Changes
v18 R6	Added

.isAdminProtected() : Boolean

Parameter	Type		Description
Result	Boolean	<-	True if the Data Explorer access is disabled, False if it is enabled (default)

Description

The .isAdminProtected() function returns True if Data Explorer access has been disabled for the working session.

By default, the Data Explorer access is granted for webAdmin sessions, but it can be disabled to prevent any data access from administrators (see the .setAdminProtection() function).

.makeSelectionsAlterable()

History

Version	Changes
v18 R5	Added

.makeSelectionsAlterable() | Parameter | Type | | Description | | --------- | ---- |::| ------------------------------- | | | | | Does not require any parameters |

Description

The .makeSelectionsAlterable() function sets all entity selections as alterable by default in the current application datastores (including remote datastores). It is intended to be used once, for example in the On Startup database method.

When this function is not called, new entity selections can be shareable, depending on the nature of their "parent", or how they are created.

This function does not modify entity selections created by .copy() or OB Copy when the explicit ck shared option is used.

Compatibility: This function must only be used in projects converted from 4D versions prior to 4D v18 R5 and containing .add() calls. In this context, using .makeSelectionsAlterable() can save time by restoring instantaneously the previous 4D behavior in existing projects. On the other hand, using this method in new projects created in 4D v18 R5 and higher is not recommended, since it prevents entity selections to be shared, which provides greater performance and scalabitlity.

.provideDataKey()

History

Version	Changes
v17 R5	Added

.provideDataKey( curPassPhrase : Text ) : Object
.provideDataKey( curDataKey : Object ) : Object

Parameter	Type		Description
curPassPhrase	Text	->	Current encryption passphrase
curDataKey	Object	->	Current data encryption key
Result	Object	<-	Result of the encryption key matching

Description

The .provideDataKey() function allows providing a data encryption key for the current data file of the datastore and detects if the key matches the encrypted data. This function can be used when opening an encrypted database, or when executing any encryption operation that requires the encryption key, such as re-encrypting the data file.

The .provideDataKey() function must be called in an encrypted database. If it is called in a non-encrypted database, the error 2003 (the encryption key does not match the data.) is returned. Use the Data file encryption status command to determine if the database is encrypted.

The .provideDataKey() function cannot be called from a remote 4D or an encrypted remote datastore.

If you use the curPassPhrase parameter, pass the string used to generate the data encryption key. When you use this parameter, an encryption key is generated.

If you use the curDataKey parameter, pass an object (with encodedKey property) that contains the data encryption key. This key may have been generated with the New data key command.

If a valid data encryption key is provided, it is added to the keyChain in memory and the encryption mode is enabled:

all data modifications in encryptable tables are encrypted on disk (.4DD, .journal. 4Dindx files)
all data loaded from encryptable tables is decrypted in memory

Result

The result of the command is described in the returned object:

Property		Type	Description
success		Boolean	True if the provided encryption key matches the encrypted data, False otherwise
			Properties below are returned only if success is FALSE
status		Number	Error code (4 if the provided encryption key is wrong)
statusText		Text	Error message
errors		Collection	Stack of errors. The first error has the highest index
	[ ].componentSignature	Text	Internal component name
	[ ].errCode	Number	Error number
	[ ].message	Text	Error message

If no curPassphrase or curDataKey is given, .provideDataKey() returns null (no error is generated).

Example

 var $keyStatus : Object
 var $passphrase : Text

 $passphrase:=Request("Enter the passphrase")
 If(OK=1)
    $keyStatus:=ds.provideDataKey($passphrase)
    If($keyStatus.success)
       ALERT("You have provided a valid encryption key")
    Else
       ALERT("You have provided an invalid encryption key, you will not be able to work with encrypted data")
    End if
 End if

.setAdminProtection()

History

Version	Changes
v18 R6	Added

.setAdminProtection( status : Boolean )

Parameter	Type		Description
status	Boolean	->	True to disable Data Explorer access to data on the `webAdmin` port, False (default) to grant access

Description

The .setAdminProtection() function allows disabling any data access on the web admin port, including for the Data Explorer in WebAdmin sessions.

By default when the function is not called, access to data is always granted on the web administration port for a session with WebAdmin privilege using the Data Explorer. In some configurations, for example when the application server is hosted on a third-party machine, you might not want the administrator to be able to view your data, although they can edit the server configuration, including the access key settings.

In this case, you can call this function to disable the data access from Data Explorer on the web admin port of the machine, even if the user session has the WebAdmin privilege. When this function is executed, the data file is immediately protected and the status is stored on disk: the data file will be protected even if the application is restarted.

Example

You create a protectDataFile project method to call before deployments for example:

 ds.setAdminProtection(True) //Disables the Data Explorer data access

.startRequestLog()

History

Version	Changes
v17 R6	Added

.startRequestLog()
.startRequestLog( file : 4D.File )
.startRequestLog( reqNum : Integer )

Parameter	Type		Description
file	4D.File	->	File object
reqNum	Integer	->	Number of requests to keep in memory

Description

The .startRequestLog() function starts the logging of ORDA requests on the client side.

This function must be called on a remote 4D, otherwise it does nothing. It is designed for debugging purposes in client/server configurations.

The ORDA request log can be sent to a file or to memory, depending on the parameter type:

If you passed a file object created with the File command, the log data is written in this file as a collection of objects (JSON format). Each object represents a request.
If the file does not already exist, it is created. Otherwise if the file already exists, the new log data is appended to it. If .startRequestLog( ) is called with a file while a logging was previously started in memory, the memory log is stopped and emptied.

A ] character must be manually appended at the end of the file to perform a JSON validation

If you passed a reqNum integer, the log in memory is emptied (if any) and a new log is initialized. It will keep reqNum requests in memory until the number is reached, in which case the oldest entries are emptied (FIFO stack).
If .startRequestLog() is called with a reqNum while a logging was previously started in a file, the file logging is stopped.
If you did not pass any parameter, the log is started in memory. If .startRequestLog() was previously called with a reqNum (before a .stopRequestLog()), the log data is stacked in memory until the next time the log is emptied or .stopRequestLog() is called.

For a description of the ORDA request log format, please refer to the ORDA client requests section.

Example 1

You want to log ORDA client requests in a file and use the log sequence number:

 var $file : 4D.File
 var $e : cs.PersonsEntity

 $file:=File("/LOGS/ORDARequests.txt") //logs folder

 SET DATABASE PARAMETER(Client Log Recording;1) //to trigger the global log sequence number
 ds.startRequestLog($file)
 $e:=ds.Persons.get(30001) //send a request
 ds.stopRequestLog()
 SET DATABASE PARAMETER(Client Log Recording;0)

Example 2

You want to log ORDA client requests in memory:

 var $es : cs.PersonsSelection
 var $log : Collection

 ds.startRequestLog(3) //keep 3 requests in memory

 $es:=ds.Persons.query("name=:1";"Marie")
 $es:=ds.Persons.query("name IN :1";New collection("Marie"))
 $es:=ds.Persons.query("name=:1";"So@")

 $log:=ds.getRequestLog()
 ALERT("The longest request lasted: "+String($log.max("duration"))+" ms")

.startTransaction()

History

Version	Changes
v18	Added

.startTransaction() | Parameter | Type | | Description | | --------- | ---- | | ------------------------------- | | | | | Does not require any parameters |

Description

The .startTransaction() function starts a transaction in the current process on the database matching the datastore to which it applies. Any changes made to the datastore's entities in the transaction's process are temporarily stored until the transaction is either validated or cancelled.

If this method is called on the main datastore (i.e. the datastore returned by the ds command), the transaction is applied to all operations performed on the main datastore and on the underlying database, thus including ORDA and classic languages.

You can nest several transactions (sub-transactions). Each transaction or sub-transaction must eventually be cancelled or validated. Note that if the main transaction is cancelled, all of its sub-transactions are also cancelled even if they were validated individually using the .validateTransaction() function.

Example

 var $connect; $status : Object
 var $person : cs.PersonsEntity
 var $ds : cs.DataStore
 var $choice : Text
 var $error : Boolean

 Case of
    :($choice="local")
       $ds:=ds
    :($choice="remote")
       $connect:=New object("hostname";"111.222.3.4:8044")
       $ds:=Open datastore($connect;"myRemoteDS")
 End case

 $ds.startTransaction()
 $person:=$ds.Persons.query("lastname=:1";"Peters").first()

 If($person#Null)
    $person.lastname:="Smith"
    $status:=$person.save()
 End if
 ...
 ...
 If($error)
    $ds.cancelTransaction()
 Else
    $ds.validateTransaction()
 End if

.stopRequestLog()

History

Version	Changes
v17 R6	Added

.stopRequestLog()
| Parameter | Type | | Description | | --------- | ---- | | ------------------------------- | | | | | Does not require any parameters |

Description

The .stopRequestLog() function stops any logging of ORDA requests on the client side (in file or in memory). It is particularly useful when logging in a file, since it actually closes the opened document on disk.

This function must be called on a remote 4D, otherwise it does nothing. It is designed for debugging purposes in client/server configurations.

Example

See examples for .startRequestLog().

.validateTransaction()

History

Version	Changes
v18	Added

.validateTransaction()
| Parameter | Type | | Description | | --------- | ---- | | ------------------------------- | | | | | Does not require any parameters |

Description

The .validateTransaction() function accepts the transaction that was started with .startTransaction() at the corresponding level on the specified datastore.

The function saves the changes to the data on the datastore that occurred during the transaction.

Example

See example for .startTransaction().

Summary

ds

Description

Example 1

Example 2

Open datastore

Description

Example 1

Example 2

Example 3

Error management

.dataclassName

Description

Example

.cancelTransaction()

Description

Example

.encryptionStatus()

Description

Example

.getInfo()

Description

Example 1

Example 2

.getRequestLog()

Description

Example

.isAdminProtected()

Description

See also

.makeSelectionsAlterable()

Description

.provideDataKey()

Description

Example

.setAdminProtection()

Description

Example

See also

.startRequestLog()

Description

Example 1

Example 2

.startTransaction()

Description

Example

.stopRequestLog()

Description

Example

.validateTransaction()

Description

Example