Sql Text Transmission (Communication Action) - Mitsubishi Electric Melsec Q Series User Manual

6
FUNCTIONS

6.1.6 SQL text transmission (Communication action)

The SQL text transmission function allows automatic creation of SQL texts, enabling
communications with the database.
The following commands can be selected for the SQL text.
• Select/MultiSelect
• Update
• Insert
• Delete
For the SQL text transmission setting, refer to the following:
Section 7.11.1 Setting items in Communication action
Select/MultiSelect
Tag Component
Temporary
variable*
Update*
Tag Component
Temporary variable
Constant
Insert
Tag Component
Temporary variable
Constant
Delete*
(1) Select/MultiSelect
Select/MultiSelect is used to write a database value to a tag component value area or
to store it in the temporary variable area by sending a SQL text to the database.
When a value is stored in the temporary variable area, it can be used as a variable for
other actions.
(2) Update and Insert
Update and Insert are used to embed a tag component value or a temporary variable
in an SQL text and write the value to the database.
(3) Delete
Delete is used to eliminate a record from the database.
Select/MultiSelect
Data
1
2
Update
Data
Insert
Data
2
Delete
* 3
Figure 6.8 SQL text transmission (Communication action)
*1 It cannot be used for MultiSelect.
*2 When accessing the same data which is locked in the database, the processing may be delayed
until the data is unlocked. Do not access the data that may be locked for a long time.
*3 There is no data communication.
Once records are deleted from the database, they cannot be restored.
Make sure that correct target record and timing are set for the delete action.
6.1.6 SQL text transmission (Communication action)
Database server computer
Database
6.1 DB Interface Function
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