ECPG insert into table name as a variable
От | Lee Kindness |
---|---|
Тема | ECPG insert into table name as a variable |
Дата | |
Msg-id | 16241.50701.544612.198427@kelvin.csl.co.uk обсуждение исходный текст |
Ответ на | ECPG insert into table name as a variable (Ryan Mooney <ryan@pcslink.com>) |
Список | pgsql-interfaces |
No, not like that. But it'd be nice... No do what you want consider something along the lines of: snprintf(l_cmd, sizeof(l_cmd), "ALTER TABLE %s ADD COLUMN %s%d FLOAT4 NULL", tables[t].table, tables[t].column,n);EXEC SQL EXECUTE IMMEDIATE :l_cmd; or, more useful: else snprintf(l_cmd, sizeof(l_cmd), "SELECT src.shot, %s FROM %s src WHERE %s IS NOT NULL AND channel = %d", attribute,table, nullattr, channel); EXEC_SQL_BEGIN; /* declare & open */ EXEC SQL PREPARE lofsdb_SelectAttr_stmt FROM :l_cmd; EXEC SQL DECLARE lofsdb_SelectAttr_cur CURSORFOR lofsdb_SelectAttr_stmt; EXEC SQL OPEN lofsdb_SelectAttr_cur; and then just treat the CURSOR as normal... But for INSERTs the first EXECUTE IMMEDIATE will do. L. Ryan Mooney writes:> > > I was doing testing on an app and wanted to make a table name a variable> so I can change it viaa config file (instead of re-compile/relink).> > like so:> EXEC SQL INSERT INTO :tname (host, point, type, cooked) VALUES(:host, :name, :type, :cooked);> > This fails ecpg preprocess with "ERROR: syntax error at or near ":tname" whereasif the table > name is specified statically it works fine, like:> EXEC SQL INSERT INTO tname (host, point, type,cooked) VALUES (:host, :name, :type, :cooked);> > When I tried hacking the resulting C code (as a test exercise) like:>> { ECPGdo(__LINE__, 0, 1, NULL, "insert into ? ( host , point , type , cooked ) values ( ? , ? , ? , ? )",> ECPGt_char,&(tname),(long)0,(long)1,1*sizeof(char),> ECPGt_char,&(host),(long)0,(long)1,1*sizeof(char),> ECPGt_NO_INDICATOR,NULL , 0L, 0L, 0L,> ECPGt_char,&(name),(long)0,(long)1,1*sizeof(char),> ECPGt_NO_INDICATOR, NULL ,0L, 0L, 0L,> ECPGt_char,&(type),(long)1,(long)1,1*sizeof(char),> ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L,> ECPGt_char,&(cooked),(long)1,(long)1,1*sizeof(char),> ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L,> ECPGt_char,(starttime),(long)30,(long)1,30*sizeof(char),> ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L,> ECPGt_char,(interval),(long)30,(long)1,30*sizeof(char),> ECPGt_NO_INDICATOR, NULL , 0L, 0L, 0L,> > it got all funny anddidn't work very well (well ok it didn't work at all):> pg.pgc:129 SQL Insert failed: Invalid statement name (null)in line 124.> > So, I was wondering am I just missing some obvious way to do this, or> is this not supported at all?>> Thanks> > > -- > >-=-=-=-=-=-=-<>-=-=-=-=-=-<>-=-=-=-=-=-<>-=-=-=-=-=-<>-=-=-=-=-=-=-<> Ryan Mooney ryan@pcslink.com > <-=-=-=-=-=-=-><-=-=-=-=-=-><-=-=-=-=-=-><-=-=-=-=-=-><-=-=-=-=-=-=->
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