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Programming Q Parameters | Accessing tables with SQL commands
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HEIDENHAIN | TNC 640 | Conversational Programming User's Manual | 10/2017
10.9 Accessing tables with SQL commands
Introduction
If you would like to access numerical or alphanumerical
content in a table or manipulate the table (e.g., rename
columns or rows), then use the SQL commands
available to you.
The syntax of the SQL commands available on the
control is heavily influenced by the SQL programming
language—but does not conform to it completely. In
addition, the control does not support the entire scope
of the SQL language.
The names of tables and table columns must start with
a letter and must not contain an arithmetic operator
(e.g.,
+
). Due to SQL commands, these characters can
cause problems when inputting data or reading it out.
The following terms will be used (along with others) in
the following:
“SQL command” refers to the available soft keys
“SQL instructions” describe miscellaneous functions
that are entered manually as part of the syntax
In the syntax,
HANDLE
stands for a transaction
(followed by the identifying parameter)
The
Result set
contains the query result (referred to
in the following as “intermediate memory”)
Read and write access to individual numerical values of
a table can likewise be carried out using the function
FN
26: TABOPEN
,
FN 27: TABWRITE
and
FN 28: TABREAD
.
Further information: "Freely definable tables",
page 570
In the NC software, access to tables is gained via an SQL server.
This server is controlled with the available SQL commands. The
SQL commands can be defined directly in an NC program.
The saver is based on a transaction model. A transaction is made
up of multiples steps that are executed together, thereby ensuring
an orderly and defined processing of the table entries.