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---+ Linking <nop>PostgreSQL Database Objects into Virtuoso

---++ Steps

   1. Start the Virtuoso Web User Interface.
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   2. Select the *Conductor* link in the left frame and login as the *dba* user.
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   3. Select the *Databases* -> *External Data Source* -> *Data Sources* tab menu items.
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   4. Select the *Connect* button for the *pg7ma* <nop>PostgreSQL DSN.
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   5. On successful connection, select the *Link Objects* button to obtain a list of available tables.
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   6. Select all the tables that you would like to link.
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   7. Change the Catalog for each table to be *PGR* using the *Set All* button.
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   8. All the catalog names are changed to *PGR*.
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   9. Select the *Link* button to link the selected tables into Virtuoso.
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   10. On completion of the Link process, the tables will be displayed in the *External Linked Objects* tab.
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   11. The linked tables can be queried by clicking on the hyperlink in the *Local Name* column of the *External Linked Objects* tab above. This loads the Virtuoso *Interactive SQL* interface with the required SQL *Select* for retrieving the remote table data. We shall use the *PGR.PGR.Customers* table to demonstrate this.
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   12.  Click the *Execute* button to run the query and retrieve results from the remote table.
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   13.  The tables can also be viewed as part of the Virtuoso *SQL Schema Objects* under the *PGR* catalog name.
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The Link process is now complete enabling the tables to be queried as if part of the Virtuoso Schema.

---++ Related

   * [[VOSSQL2RDF][Mapping SQL Data to Linked Data Views]]
   * [[VirtPostgresEntityFrameworkUsage][Using Microsoft Entity Frameworks to Access PostgreSQL Schema Objects with Virtuoso]]


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