Abstract: Provided is a technique enables programming, including that for database operations, without describing a SQL used to operate the database. A PLC (30) that can access a DBMS (22) stores a user program (38) and definition information (32), the user program (38) including a structure type of variable, the definition information (32) indicating a definition of the structure type. The sequence command program (34) sequentially executes instructions in the user program (38) and invokes a DB access process program (35) in order to access the DBMS (22). The DB access process program (35) reads the definition information (32) and, on the basis of the read definition information (32), generates a SQL statement to be used when access to the DBMS (22) is made by execution of the user program (38). The DB access process program (35) executes the generated SQL statement by transmitting the SQL statement to the DB server (20).

Abstract: A technique for facilitating debugging in a user program which operates by cooperation of a PLC and another system in a control system including a controller and another system. A CPU unit has a communication interface, executes a user program, calls DB connection service in accordance with an instruction included in the user program, and generates a statement to access a database device. In the DB connection service, operation is performed while switching a first mode and a second mode. In the first mode, a statement according to an access instruction is generated, the generated statement is transmitted to a database system, and a result of a response is sent to the user program. In the second mode, without transmitting the statement to the database device, a result of execution corresponding to the statement is sent to the user program.

Abstract: Provided is a technique enables programming, including that for database operations, without describing a SQL used to operate the database. A PLC (30) that can access a DBMS (22) stores a user program (38) and definition information (32), the user program (38) including a structure type of variable, the definition information (32) indicating a definition of the structure type. The sequence command program (34) sequentially executes instructions in the user program (38) and invokes a DB access process program (35) in order to access the DBMS (22). The DB access process program (35) reads the definition information (32) and, on the basis of the read definition information (32), generates a SQL statement to be used when access to the DBMS (22) is made by execution of the user program (38). The DB access process program (35) executes the generated SQL statement by transmitting the SQL statement to the DB server (20).

Abstract: A technique capable of efficiently performing debugging in a program and checking of soundness in a control system including a controller and a database system. A CPU unit has a communication interface for connection to a database device. The CPU unit executes a user program to call a DB connection service in accordance with an instruction included in the user program and generate a statement to access the database device. In the DB connection service, a statement according to an access instruction is generated, and the generated statement is transmitted to a database system. After that, information indicative of time until a response from the database system is received is acquired, and the acquired information is stored as a log into a memory. A support device acquires the information and displays it on a monitor.

Abstract: A technique for facilitating debugging in a user program which operates by cooperation of a PLC and another system in a control system including a controller and another system. A CPU unit has a communication interface, executes a user program, calls DB connection service in accordance with an instruction included in the user program, and generates a statement to access a database device. In the DB connection service, operation is performed while switching a first mode and a second mode. In the first mode, a statement according to an access instruction is generated, the generated statement is transmitted to a database system, and a result of a response is sent to the user program. In the second mode, without transmitting the statement to the database device, a result of execution corresponding to the statement is sent to the user program.