OPEN ALLOWING READERS is not supported by Informix. You determine in your runtime configuration file how this phrase will be interpreted. Set the variable STRENGTHEN-LOCKS to 1 (one) to cause this phrase to be treated as OPEN ALLOWING NO OTHERS. Set the variable to 0 (zero) to cause the phrase to be treated as OPEN ALLOWING ALL. The default value is 0.
Only single-record locking is supported, unless the program is within a transaction.
If you attempt to REWRITE a record that contains a SERIAL data type, you will receive an Informix error. You might want to change SERIAL fields to SMALLINT, as we do for the orders table in the demonstration.
Informix does not support record encryption, record compression, or alternate collating sequences. You may include these options in your program; they will be disregarded if they are specified.
The ACUCOBOL-GT utility program vutil cannot be used with Informix files. Instead, use utilities supplied by Informix.
Whenever you are using the library routine RENAME, you must specify that you are using indexed files. This information is passed by the value I in the fourth parameter. If you want to delete an Informix table with the DELETE FILE verb, make sure the verb references an indexed file.
In the past, the Acu4GL for Informix product would ignore some of the transaction flags sent by the runtime. This could lead to unexpected behavior, especially if the program were compiled with the -ft option. The runtime would sometimes return an error 9E,535, or not be in the transaction state expected. Acu4GL now passes all transaction operations on to the database. If you want to use the transaction rules used in Version 1.3, you can set the configuration variable "4GL_1_3_TRANSACTIONS=1". The default value is zero.
Passing all transaction flags to the database may have the unexpected effect of releasing a lock due to the COMMIT of a transaction. Acu4GL for Informix performs REWRITE and DELETE operations on the current record through the record lock using the syntax "WHERE CURRENT OF". If this is a problem, Acu4GL can be told to use an alternate method of explicitly specifying the primary key in the REWRITE and DELETE operations by setting the configuration variable: "4GL_POSITIONED_MODIFICATIONS = 0". The default is 1. You should note that database systems will not perform well with applications compiled with the "-ft" option. You should consider explicitly coding the transactions.