May 2, 2000

Meanings of RS232 Signals

Question: Can you explain the interaction of the RS232 signals (RTS, CTS, DTR, etc.). I need to write a software utility to transmit and receive characters between two computers, but I am unsure about the order of raising/lowering signals and checking for them. I also don’t quite understand them when

Using Where on Fields of Differing Types

Question: I need to extract information using WHERE on fields in two different tables: one a text field, the other a numeric field. Both hold only numeric data. How can I do this? Answer: If by the term text field you mean varchar, you can convert the column data using

Problem with Select Statement

Question: I’m writing a select statement to make a table name a variable whose value is set according to a condition: Var tablename;tablename := emp tableselect * from tablename; But I get an error message. How do I make this statement work? Answer: Your syntax is close to what you

Finding Out if a User Has Disabled Cookies

Question: How do I find out if a user has disabled cookies? Answer: To find out if a user has disabled cookies, follow these steps: Set a cookie. Redirect to your own page. In the redirect, read the cookie. If your cookie has a value, user has enabled cookies. If

Informix Data Types for Linking Images

Question: Does Informix have a data type similiar to SQL Server’s image or ntext to input paths to link images? Answer: I’d use a CHAR(25) or a VARCHAR field for that. It’s just a string field, so you’ll have to build and interpret it through code.

Effects of Operator delete

Question: Why, after deleting an object I allocated dynamically, is the pointer still there? What exactly have I deleted and what would happen if I assigned a new value to the pointer without nullifying it first? Answer: You delete the object, not the pointer. The pointer’s value doesn’t chang when

WAP IP Address

Question: Does WAP have a concept of IP address? Answer: You can get the gateway IP address and the terminal IP address using HTTP headers. WAP 1.1 currently has no persistent way of identifying each device that connects (i.e., each time you reconnect you are assigned another “IP”). Some discussion

Percent Sign in SQL

Question: I have a table in which the key field has a value stored with a percent sign, like ‘1234%’.Using this value, I want to select from another table that can have values like ‘1234567’, ‘1234678’ and ‘1234098’. How do I go about it? Answer: The percent sign (%) is

ESQL/C (9.2) UC3 Errors

Question: I have installed the version 9.2 of ESQLC, and when I try to run the program in the following manner: esql -e cc -c -I/home/informix/incl/esql crdb.c cc -ocrdb7.exe crdb.o home/informix/lib/esql/libgen.a /home/informix/lib/esql/libos.a /home/informix/lib/esql/libsql.a We get the following error: NCR High Performance C Compiler R3.0c(c) Copyright 1994-97, NCR Corporation(c) Copyright

No more posts to show