Thanks to all for your help, especially Mr. Lam. Your response, Mr. Lam, was very instructive. I used your input to explore a bit more, with a couple of questions arising.
See the questions embedded below: ***************************** load 'data/jdb' ffd =: Open_jdb_ jpath , '~temp' Drop__ffd 'testdb' db =: Create__ffd 'testdb' ht=: Create__db 'tblChar';0 : 0 c1 char ) NB. JDB doc says a 'char' column is stored as a character matrix NB. The next sentence works, even though it inserts a scalar, 'a' NB. QUESTION: Is this contrary to the JDB doc? Insert__db 'tblChar';'a' ]shape =. $'a' NB. Inserts a list of shape 1 Insert__db 'tblChar';,'b' ]shape =. $ ,'b' NB. Inserts a list of shape 3 1 Insert__db 'tblChar';,.'def' ]shape =. $ ,.'def' NB. Inserts a list of shape 1 4 Insert__db 'tblChar';,:'ghih' ]shape =. $ ,:'ghih' Insert__db 'tblChar';3 5 $'123457' Insert__db 'tblChar';,:'012345678901234567890' ]shape=.$ ,:'012345678901234567890' NB. A JDB 'char' column allows chars of varying lengths to be inserted Insert__db 'tblChar';2 100$'1234567890' Reads__db 'from tblChar' NB. The insert below causes a failure NB. After this the table can no longer be read. NB. QUESTION: Is that behavior intended? NB. If so, JDB seems a little fragile for the rough, unskilled hands of newbies like me NB. This insert, where '01' is a list of shape 2, fails even though an insert of 'b', a list of shape 1 worked above. NB. QUESTION: Is this behavior consistent in a way that I am not understanding? Insert__db 'tblChar';'01' Reads__db 'from tblChar' Thanks again for the high quality help & instruction. --chris-- ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
