When it comes to SQL Server, the cleaning and removal of ASCII Control Characters are a bit tricky. Only using advanced text editors such as Notepad++ are we then able to visualize the special characters in the data, as shown in Figure 4. In fact, it looks like the email address 3 and 4 have the same amount of characters – which is not true. Furthermore, if you go back to Script 4, you will recall that for the 3 rd email address, I included the start of header character at the end of the email address, but looking at the data in Figure 3, the start of header character is not easily visible at the end of that 3 rd email address.
ALT CODE ZERO WITH SLASH WINDOWS
To demonstrate the challenge of cleaning up ASCII Control Characters, I have written a C# Console application shown in Script 4 that generates an output.txt text file that contains different variations of John Doe’s email address (only the first line has John Doe’s email address in the correct format).Ī preview of the output.txt text file populated by Script 4 is shown using the Windows Notepad.exe program in Figure 3.Īs it can be seen, there seem to be spaces in email address 2-4 but it’s difficult to tell whether these spaces are created by the Tab character or the Space bar character.
Table 2: Top 5 ASCII control characters (Source: ) Table 2 shows a sample list of the ASCII Control Characters.
Such characters typically are not easy to detect (to the human eye) and thus not easily replaceable using the REPLACE T-SQL function. In addition to ASCII Printable Characters, the ASCII standard further defines a list of special characters collectively known as ASCII Control Characters. SELECT REPLACE ( REPLACE ( REPLACE ( email, '!', '' ), '#', '' ), '$', '' ) Įxecution of Script 3 results into a correctly formatted email address that is shown in Figure 2.įigure 2 Replacing ASCII Control Characters Script 1 shows us an example of how an ASCII numeric code 92 can be converted back into a backslash character as shown in Figure 1. Likewise, SQL Server, which uses ANSI – an improved version of ASCII, ships with a built-in CHAR function that can be used to convert an ASCII numerical code back to its original character code (or symbol).
ALT CODE ZERO WITH SLASH SOFTWARE
Many of the software vendors abide by ASCII and thus represents character codes according to the ASCII standard. For instance, the ASCII numeric code associated with the backslash ( \ ) character is 92. The American Standard Code for Information Interchange (ASCII) is one of the generally accepted standardized numeric codes for representing character data in a computer. In this article, we take a look at some of the issues you are likely to encounter when cleaning up source data that contains ASCII special characters and we also look at the user-defined function that could be applied to successfully remove such characters. One aspect of transforming source data that could get complicated relates to the removal of ASCII special characters such as new line characters and the horizontal tab. This could involve looking up foreign keys, converting values from one data type into another, or simply conducting data clean-ups by removing trailing and leading spaces. One of the important steps in an ETL process involves the transformation of source data.
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