diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/developers.bb | 3 | ||||
| -rw-r--r-- | doc/sql_conventions.bb | 87 |
2 files changed, 90 insertions, 0 deletions
diff --git a/doc/developers.bb b/doc/developers.bb index 18e39c4ea..5365fd77a 100644 --- a/doc/developers.bb +++ b/doc/developers.bb @@ -64,4 +64,7 @@ In the interests of consistency we adopt the following code styling. We may acce [li] Generally speaking, opening braces go on the same line as the thing which opens the brace. They are the last character on the line. Closing braces are on a line by themselves. [/li]
+[b]See Also[/b]
+[zrl=[baseurl]/help/sql_conventions]SQL Conventions[/zrl]
+
#include doc/macros/main_footer.bb;
diff --git a/doc/sql_conventions.bb b/doc/sql_conventions.bb new file mode 100644 index 000000000..88539ae19 --- /dev/null +++ b/doc/sql_conventions.bb @@ -0,0 +1,87 @@ +[h1]SQL Conventions[/h1] +[b]Intro[/b] +The following common SQL conventions appear throughout the code in many places. We use a simple DBA (DataBase Abstraction layer) to handle differences between databases. Please be sure to use only standards-compliant SQL. + +[b]Rule One[/b] +Worth Repeating: Don't use non-standard SQL. This goes for addons as well. If you do use non-standard SQL, and the dba funcs are insufficient, do a if()/switch() or similar for all currently supported databases. Currently nothing red# does requires non-standard SQL. + +[b]Using a format string[/b] +[li]Uses sprintf() +To be written +[code]// Example +$r = q("SELECT * FROM profile WHERE uid = %d", + local_user() +); +[/code][/li] + +[b]Checking bit flags in a where clause[/b] +[li]You must explicitly convert integers to booleans. The easiest way to do this is to compare to 0. +[code]// Example +$r = q("SELECT abook_id, abook_flags, abook_my_perms, abook_their_perms, xchan_hash, xchan_photo_m, xchan_name, xchan_url from abook left join xchan on abook_xchan = xchan_hash where abook_channel = %d and not (abook_flags & %d)>0 ", + intval($uid), + intval(ABOOK_FLAG_SELF) +); +[/code] +[/li] +[li]Turning off a flag +[code]$y = q("update xchan set xchan_flags = (xchan_flags & ~%d) where (xchan_flags & %d)>0 and xchan_hash = '%s'", + intval(XCHAN_FLAGS_ORPHAN), + intval(XCHAN_FLAGS_ORPHAN), + dbesc($rr['hubloc_hash']) +);[/code] +[/li] +[li]Turning on a flag +[code]$y = q("update xchan set xchan_flags = (xchan_flags | %d) where xchan_hash = '%s'", + intval(XCHAN_FLAGS_ORPHAN), + dbesc($rr['hubloc_hash']) +);[/code] +[/li] + +[b]Using relative times (INTERVALs)[/b] +[li]Sometimes you want to compare something, like less than x days old. +[code]// Example +$r = q("SELECT * FROM abook left join xchan on abook_xchan = xchan_hash + WHERE abook_dob > %s + interval %s and abook_dob < %s + interval %s", + db_utcnow(), db_quoteinterval('7 day'), + db_utcnow(), db_quoteinterval('14 day') +);[/code] +[/li] +[b]Paged results[/b] +[li]To be written +[code]// Example +$r = q("SELECT * FROM mail WHERE uid=%d AND $sql_extra ORDER BY created DESC LIMIT %d OFFSET %d", + intval(api_user()), + intval($count), intval($start) +);[/code][/li] + +[b]NULL dates[/b] +[li]To be written +[code]Example[/code][/li] + +[b]Storing binary data[/b] +[li]To be written +[code]// Example +$x = q("update photo set data = '%s', height = %d, width = %d where resource_id = '%s' and uid = %d and scale = 0", + dbescbin($ph->imageString()), + intval($height), + intval($width), + dbesc($resource_id), + intval($page_owner_uid) +);[/code][/li] + +[b]Current timestamp[/b] +[li][code]// Example +$randfunc = db_getfunc('rand'); +$r = q("select xchan_url from xchan left join hubloc on hubloc_hash = xchan_hash where hubloc_connected > %s - interval %s order by $randfunc limit 1", + db_utcnow(), db_quoteinterval('30 day') +);[/code][/li] + +[b]SQL Function and Operator Abstraction[/b] +[li]Sometimes the same function or operator has a different name/symbol in each database. You use db_getfunc('funcname') to look them up. The string is [i]not[/i] case-sensitive; do [i]not[/i] include parens. +[code]// Example +$randfunc = db_getfunc('rand'); +$r = q("select xchan_url from xchan left join hubloc on hubloc_hash = xchan_hash where hubloc_connected > %s - interval %s order by $randfunc limit 1", + db_utcnow(), db_quoteinterval('30 day') +);[/code][/li] + +#include doc/macros/main_footer.bb;
\ No newline at end of file |