Structured Query Language (SQL)

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Structured Query Language (SQL)

Structured Query Language, or SQL, is a language for managing data in relational databases. Fernhill SCADA supports the SQL SELECT statement to retrieve data and the SQL UPDATE command to update tag values. You can use SQL in a variety of ways for example:

The SELECT statement

The SELECT statement is used to retrieve data from the Fernhill SCADA database. The format of the SELECT statement is:

query-specification ::= SELECT [ ALL | DISTINCT ] select-list
  table-expression

Query Expressions

You can combine the result of one or more SELECT statements into a single result set using a Query Expression. The result of the Query Expression can be sorted using an optional ORDER BY clause. The number of rows returned in the result can be restricted using optional OFFSET and FETCH clauses.

query-expression ::= query-expression-body
  [order-by-clause]
  [result-offset-clause]
  [fetch-first-clause]

The UPDATE Command

The UPDATE command is used to update tag values in Fernhill SCADA. The format of the UPDATE command is:

update-command ::= UPDATE table-name
  SET set-clause-list
  [WHERE search-condition ]

Schema Information

You can explore the data schema in Fernhill SCADA using the SQL Test Tool. Choose an option from the File, Open Schema menu to browse the schema information.

Further Information

.NET Framework Data Provider

To learn about the .NET Framework Data Provider in Fernhill SCADA (FernhillSoftware.Data.FernhillScadaClient).

ODBC driver

To learn about the ODBC driver in Fernhill SCADA.

SQL Test Tool

To learn about the SQL Test Tool.

Glossary

For the meaning of terms used in Fernhill SCADA.