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how can i get column name of a table

zb cong
Ranch Hand

Joined: Jan 14, 2002
Posts: 416
hello
in one of my project,i want to get the column names of a unknown table,i can get it by the ResultSetMetaData.getColumnCount(int col) method,but i must execute a query first,because i know nothing about the table,the only choice is "select * from myTable",then navigate the resultset.but maybe this table have thousands of records,i only want to get the COLUMN NAME,not the record,so this method is not effective,who can give me a more effective code snippet?such as retrieve the column names of the emp table(in oracle sample database-----scott/tiger).
thank you!
Calvin Yan
Greenhorn

Joined: Jun 25, 2003
Posts: 19
you may concentrate on the part of ResultSetMetaData instance:
public class odbctest
{
public static void main(String[] argu)
{
try
{
Connection conn;
Statement st;
ResultSet rs;
ResultSetMetaData rsmd;

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver").newInstance();
conn = DriverManager.getConnection("jdbc dbc:book");
st = conn.createStatement();
rs = st.executeQuery("select * from [Sheet1$]");
rsmd = rs.getMetaData();
int count = rsmd.getColumnCount();
System.out.println(count);
String[] field = new String[count];
if(count != 0)
{
for(int i=0; i<count; i++)
{
field[i] = rsmd.getColumnName(i+1);
//System.out.println(s);
}
}
rs = st.executeQuery("select * from [Sheet1$]");
while(rs.next())
{
String s = rs.getString(1);
System.out.println(s);
}
}
catch(Exception e)
{
System.out.println(e.toString());
}
}
}


I will do the best with what God gave me!
Avi Abrami
Ranch Hand

Joined: Oct 11, 2000
Posts: 1132

Hi Zhebin,
Have you seen the answers that I (and Elango) have provided to this very same question that you posted at the Oracle (OTN) forums?
Good Luck,
Avi.
zb cong
Ranch Hand

Joined: Jan 14, 2002
Posts: 416
to Calvin:
i don't want to execute such operation:
rs = st.executeQuery("select * from [Sheet1$]");
because i only want to get the column name,not any record in the table,such a operation maybe more resource-consuming,there may be millions of record in the table.

to Avi:
could you give me the CONCRETE link to the post,the link you have provided is pointed to the main page of the otn forum.
zb cong
Ranch Hand

Joined: Jan 14, 2002
Posts: 416
hi Avi
i have got it,that is just me,it is funny.
Wayne L Johnson
Ranch Hand

Joined: Sep 03, 2003
Posts: 399
One possible way to "cheat"--and I've tested this against several different databases--is to force the query to return no rows, something like:
rs = st.executeQuery("select * from [Sheet1$] where 1 = 2");
I've tested this against tables with over one million records and it returned almost immediately. But I still got the ResultSetMetaData and was able to determine the column names and types.
 
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