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digitalmars.D.learn - How to concat UUID into a SQL query string to MariaDB

reply Anders S <anders xore.se> writes:
Hi guys,

Using MariaDB to communicate between appz via FIFO pipe

Now I stumbled on the next problem, how to extract UUID from 
database into an UPDATE query that is a string ( the sql variable 
).

Got in a loop:

char [16][10] hash;

for(i =0; i < count; i++){

auto hash1 = row[0];

hash[i] = hash1.get!(string);

... do some FIFO Pipe work

sql = "UPDATE guirequest SET done_request = SYSDATE() WHERE 
request_id=" + hash[i] + ";";

Get this error :Error: invalid array operation "UPDATE guirequest 
SET done_request = SYSDATE() WHERE request_id=" + 
hash[cast(uint)i] (possible missing [])

Any ideas?

/a
Aug 27 2019
parent reply Jani Hur <spam com.invalid> writes:
On Tuesday, 27 August 2019 at 08:08:05 UTC, Anders S wrote:

 Any ideas?


+ is not a string concatenation. Try ~ instead:

auto x = "aa" ~ "bb" ~ "cc";
Aug 27 2019
next sibling parent Anders S <anders xore.se> writes:
On Tuesday, 27 August 2019 at 08:30:50 UTC, Jani Hur wrote:

 On Tuesday, 27 August 2019 at 08:08:05 UTC, Anders S wrote:

 Any ideas?


 + is not a string concatenation. Try ~ instead:

 auto x = "aa" ~ "bb" ~ "cc";


Hi thanks for answer, but didn't help. Got this error instead :

Error: cannot implicitly convert expression "UPDATE guirequest 
SET done_request = SYSDATE() WHERE request_id=" ~ 
cast(const(char)[])hash[cast(uint)i] ~ ";" of type char[] to 
string


Notice you use auto x .... Am I better of using something like

auto sql_respons ="UPDATE guirequest SET done_request = SYSDATE() 
WHERE request_id=" ~ hash[i] ~ ";";
Aug 27 2019
prev sibling parent reply Anders S <anders xore.se> writes:
On Tuesday, 27 August 2019 at 08:30:50 UTC, Jani Hur wrote:

 On Tuesday, 27 August 2019 at 08:08:05 UTC, Anders S wrote:

 Any ideas?


 + is not a string concatenation. Try ~ instead:

 auto x = "aa" ~ "bb" ~ "cc";


Hi again, the auto declaration worked as I expected my 
catenations should with the string

So thanks
Aug 27 2019
parent Jani Hur <spam com.invalid> writes:
On Tuesday, 27 August 2019 at 08:54:21 UTC, Anders S wrote:

 Hi again, the auto declaration worked as I expected my 
 catenations should with the string


Great to hear that !

Strings are a bit "different" in D. Please help yourself and read 
the following that IMO is the best introduction to the topic:

http://ddili.org/ders/d.en/strings.html

Also see http://ddili.org/ders/d.en/auto_and_typeof.html for auto 
keyword.
Aug 27 2019