Dheeraj wrote: > ... > I want to information about alter a table !! The ALTER TABLE command is documented at http://db.apache.org/derby/docs/10.1/ref/rrefsqlj81859.html .
> Like change column name or increase/ decrease the size of a column !! As the link above explains, you can increase the size of column, but not decrease it. But there are some restrictions that are being addressed by DERBY-396 (http://issues.apache.org/jira/browse/DERBY-396) . > I want to information about how can I see the structure of a table through a > query or etc. > > i.e how many columns currently present in a table what their size & data > type !! Derby's 'dblook' utility outputs the DDL for objects in a database: http://db.apache.org/derby/docs/10.1/tools/ctoolsgenddldb.html DERBY-1164 (http://issues.apache.org/jira/browse/DERBY-1164) is a feature request to add functionality to ij to output information. Also, some of the GUI tools listed on the Wiki page below provide nice viewing of database objects: http://wiki.apache.org/db-derby/UsesOfDerby#ProductsByType > Please give me list of what data type are convert to other data type !! A table that shows which types can be explicitly converted ("cast") to another is in the SQL Reference Guide: http://db.apache.org/derby/docs/10.1/ref/rrefsqlj33562.html And this page summarizes the data types that can be used for comparison, sorting and ordering expressions: http://db.apache.org/derby/docs/10.1/ref/rrefsqlj58560.html > ... > Pls give me these information about Apache Derby !! Much of the information you are looking for is available in the Derby manuals, which you can access from the Derby web site: http://db.apache.org/derby/manuals I hope this helps. regards, -jean
