Omron NX701-1620 User Manual page 209

If an instruction error (SQL Execution Error) occurs when the Spool function is enabled, the transmitted SQL
statement itself can be the cause of the SQL Execution Error, for example, due to a retrieval condition setting
error. Therefore, the SQL statement is not stored in the Spool memory because the SQL Execution Error may
occur again when the SQL statement is resent.
When the Spool capacity for each DB Connection is exceeded by spooling the SQL statement, this instruction is
terminated due to an error (Spool Capacity Exceeded).
Precautions for Correct Use
 Execution of this instruction is continued until processing is completed even if the value of Execute changes to
FALSE or the execution time exceeds the task period. The value of Done changes to TRUE when processing
is completed. Use this to confirm normal completion of processing.
 Refer to Using this Section of the NJ/NX-series Instructions Reference Manual (Cat. No. W502) for a timing
chart for Execute, Done, Busy, and Error.
 This instruction cannot be used on an event task. A compiling error will occur.
 This instruction cannot be executed without specifying the retrieval conditions.
 If the values cannot be registered to the DB, for example, because the SQL statement is invalid, this instruction
is terminated due to an error without storing the SQL statement into the Spool memory.
 When the DB Connection Service was started in Test Mode, this instruction is completed normally without
executing the UPDATE operation for the DB actually.
 When the error code is 300B hex (SQL Execution Error), you can get the detailed information of the SQL
Execution Error by executing a DB_GetConnectionStatus instruction
 The measurement error of timeout is +50 ms for a 100-column record when the percentage of task execution
time is 50% as a guide. However, the measurement error varies according to the percentage of task execution
time and the number of columns.
 When two or more DB Connection Instructions are executed for a DB Connection at the same time, the DB
Connection Service executes the instructions one by one. The measurement of timeout for the second and
later instructions is started when the instruction is executed by the DB Connection Service, not when the
Execute input variable is changed to TRUE. Therefore, the time from when the Execute input variable is
changed to TRUE to when the timeout occurs for the instruction is longer than the time set for the timeout.
 If a value of a DB Map Variable is changed before the DB Connection Instruction is actually executed, the new
value may be used when the DB Connection Instruction is executed. When changing a value of a DB Map
Variable, write the user program so that the value is changed after confirming completion of the DB Connection
Instruction.
 An error occurs for this instruction in the following cases. Error will be TRUE.
 When the instruction was executed when the DB Connection Service was not running
 When the instruction was executed while the initialization processing of the DB Connection Service
was in progress
 When the instruction was executed while the DB Connection Service was stopped due to an error
 When the instruction was executed after the DB Connection Service was shut down or while the DB
Connection Service was being shut down
 When the value of the DBConnection input variable is invalid or the specified DB Connection is
already closed
 When the variable specified in the MapVar input variable has not been mapped by a
DB_CreateMapping instruction
 When the Where input variable is a text string consisting of NULL characters (16#00) only
NJ/NX-series Database Connection CPU Units User's Manual (W527)
Appendix A
A
A-21