ds

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4D v19.8

ds


ds {( localID )} -> Result

Parameter	Type	Description
localID	Text	Local ID of the remote datastore to return
Result	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.

Note: 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.

For more information about datastore implementation, please refer to the Datastores section.

Example 1

Using the main datastore on the 4D database:

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

Example 2

 C_OBJECT($connectTo;$frenchStudents;$foreignStudents;$firstFrench;$firstForeign)

 

 $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

  // ---------------------

 C_TEXT($dataClassName;$2;$localId;$1)

 C_OBJECT($0)

 

 $localId:=$1

 $dataClassName:=$2

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