Hankrecords Hankrecords - 3 months ago 12
SQL Question

How to remove trailing space from SQL or javascript object column names

Before anyone starts to lynch me saying that this question has been asked thousands of times, I'd like to point out that I need to remove trailing spaces from column names, not data entries, and I haven't found any way to do this.

So, I'll explain why the question mentions both SQL and javascript objects.
I have a library (jQueryCSV) that reads a .csv file and gives me the data converted into a javascript object.

Structure: (in no particular format, I just wrote it down in a way that would be easy to read)

[
{"a ":"blahblah1","b ":"blahblah2"},
{"a ":"blahblah3","b ":"blahblah4"}
]


As you can see, the "column fields" have a trailing space in them. This wouldn't be a problem if it was a SQL database but, to query the javascript object, I'm using another library (alaSql) which allows me to use SQL queries onto javascript objects.

Thing is that, if I use this query:

alasql("SELECT a,b FROM ?", [jsObject])


which is the default alasql syntax, it doesn't recognize a and b as if they were the same as the fields with trailing spaces.

So I'm asking if there's an SQL instruction that would allow me to remove those trailing spaces from the column names (launching that instruction via alaSql) or if I'm forced to loop through the javascript object and manually change every key value (in that case, sample code would be welcome anyway!)

I figured another way might be to change the CSV file itself, but I'm trying to create an automated process so that would be pretty much pointless.

Answer

You could use one of the provided hooks to transform your csv string before converting it to an array of objects.

Hooks & Callbacks

Hooks work by defining a user-defined function that will be used inline during the parsing process. The point where it's called during parsing depends on the hook used.

Here is an example using the onParseValue hook. As you can see there is extra space in the header information of the csv string (name , age ,gender) and in the provided values (Jane Doe, 40, Female), which can easily be removed by using value.trim() in the callback for onParseValue.

const csv = `name ,age ,gender
Jane Doe, 40, Female
John Doe, 31, Male
`;
const clearData = (value, state) => value.trim();
const data = $.csv.toObjects(csv, { onParseValue: clearData });
console.log(data);
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