HEIDENHAIN TNC 640, Руководство пользователя, Страница: 437 / 948

Programming Q Parameters | Accessing tables with SQL commands
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HEIDENHAIN | TNC 640 | Conversational Programming User's Manual | 10/2017
437
Transaction
Example of an SQL transaction:
Assign Q parameters to table columns for read or write access
using
SQL BIND
Select data using
SQL SELECT
or
SQL EXECUTE
with the
SELECT
instruction
Read, change, or add data using
SQL FETCH
,
SQL UPDATE
, and
SQL INSERT
Confirm or discard interaction using
SQL COMMIT
and
SQL
ROLLBACK
Approve bindings between table columns and Q parameters
using
SQL BIND
You must conclude all transactions that have been
started—even exclusively read accesses. Concluding
the transaction is the only way to ensure that changes
and additions are transferred, that locks are removed,
and that used resources are released.
Overview of functions
Overview of soft keys
Soft
key Command Page
SQL BIND
establishes or removes connec-
tions between table columns and Q or QS
parameters
440
SQL EXECUTE
opens a transaction for
selected table columns and table rows or
enables the use of other SQL instructions
(miscellaneous functions).
Further information: "Overview of instruc-
tions", page 438
441
SQL FETCH
transfers the values to the
bound Q parameters
444
SQL ROLLBACK
discards all changes and
concludes the transaction
448
SQL COMMIT
saves all changes and
concludes the transaction
447
SQL UPDATE
transfers all values from the
bound Q parameters to the table
445
SQL INSERT
creates a new table row 446
SQL SELECT
reads out a single values from a
table and does not open any transaction
449