Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>I just wrote a quick program to show the things you've asked about... loading them up at declaration, strncpy into one of them, and then printing them out.</p> <p>Hope it helps</p> <p>edit: I kind of hate magic numbers so I almost totally removed them<br> edit: I've added alternatives Tommi Kyntola and I were talking about in the comments</p> <pre><code>#include &lt;stdio.h&gt; #include &lt;string.h&gt; // safe string copy macro, terminates string at end if necessary // note: could probably just set the last char to \0 in all cases // safely if intending to just cut off the end of the string like this #define sstrcpy(buf, src, size) strncpy(buf, src, size); if(strlen(src) &gt;= size) buf[size-1] = '\0'; #define MSGLIMIT 10 #define MSGLENGTH 30 #define MSGFIELDS 2 #define MSGNAME 0 #define MSGTEXT 1 int main(void) { char messages[MSGLIMIT][MSGFIELDS][MSGLENGTH] = { {"bla", "raa"}, {"foo", "bar"} }; int i; char *name1 = "name16789012345678901234567890"; char *text1 = "text16789012345678901234567890"; char *name2 = "name26789012345678901234567890"; char *text2 = "text26789012345678901234567890"; char *name3 = "name36789012345678901234567890"; char *text3 = "text36789012345678901234567890"; // doesn't set last char to \0 because str overruns buffer // undocumented result of running this, but likely to just get the name2 string // as that'll be the very next thing in memory on most systems strncpy(messages[2][MSGNAME], name1, MSGLENGTH); // 2 because it's the next empty one strncpy(messages[2][MSGTEXT], text1, MSGLENGTH); // alternative suggested by Tommi Kyntola // printf family are more complicated and so cost more cpu time than strncpy // but it's quick and easy anywhere you have string.h and fine most of the time snprintf(messages[3][MSGNAME], MSGLENGTH, "%s", name2); snprintf(messages[3][MSGTEXT], MSGLENGTH, "%s", text2); // uses the define macro at the top of the page to set the last char to \0 if // otherwise not set by strncpy, adds a little weight but still the better option // if performance of this section of code is important sstrcpy(messages[4][MSGNAME], name3, MSGLENGTH); sstrcpy(messages[4][MSGTEXT], text3, MSGLENGTH); for(i = 0; i &lt; 5; i++) // 5 because that's how many I've populated printf("%s : %s\n", messages[i][MSGNAME], messages[i][MSGTEXT]); return 0; } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POstrcpy and printf a multidimensional char array C
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USBen Stephens
    1. USBen Stephens
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POstrcpy and printf a multidimensional char array C
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COstrncpy usually needs some extra handling. If the message length is reached it leaves the null terminator out! Which in most cases is not what the programmer wants. Either make sure the null terminator is there or use snprintf(buf,"%s",str) which terminates even when it truncates.
      singulars
      1. PO
      1. USTommi Kyntola
    2. COYah this is true actually, with strncpy need to check if your string is bigger than your destination and deal with it if it is (just set the last char to '\0' simple solution). snprintf(buf, size, "%s", str) will do that work for you. However, if this is something your program is going to repeat many times then there's probably a performance gain in using strncpy and wrapping that check in a define macro or inline function
      singulars
      1. PO
      1. USBen Stephens
    3. COThanks Tommi, I've added some of this to the example.
      singulars
      1. PO
      1. USBen Stephens
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload