USE EXTERNAL DATABASE

version 11

USE EXTERNAL DATABASE (sourceName{; user; password})

The USE EXTERNAL DATABASE command establishes a connection between the 4D application and the data source designated by the sourceName parameter. You can get a list of data sources available on the machine using the GET DATA SOURCE LIST command.

Once the connection is established, all SQL statements executed within Begin SQL/End SQL structures from then on will be sent to this source (SQL pass-through) in the current process, until the USE INTERNAL DATABASE command or another USE EXTERNAL DATABASE statement is executed.

Note: The EXECUTE IMMEDIATE SQL statement cannot be used within a connection to an external data source.

Pass any ID information required by the data source in the user and password parameters.

   C_TEXT(sourceNamesArr;sourceDriversArr;0)
   GET DATA SOURCE LIST(1;sourceNamesArr;sourceDriversArr)  `User data sources
   If (Find in array(sourceNamesArr;"emp")#-1)  `If the source emp does exist
      USE EXTERNAL DATABASE("emp";"tiger";"scott")
      Begin SQL
      ... `SQL statements
      End SQL
   End if

Get current data source, GET DATA SOURCE LIST, USE INTERNAL DATABASE.

If the command is executed correctly, the OK system variable is set to 1. Otherwise, it is set to 0 and an error is generated.