从Java运行Oracle查询

Question

I want to run the query: "DESCRIBE table_name;"

statement = this.connection.createStatement();
ResultSet rset = statement.executeQuery("DESCRIBE table_name");

and I got this error:

 " java.sql.SQLSyntaxErrorException: ORA-00900: invalid SQL statement"

what is the problem?

Answer 1

DESC[RIBE] is a SQL*Plus command, not a SQL statement. The DESC command queries the Oracle data dictionary, something like:

select COLUMN_NAME, DATA_TYPE
  from USER_TAB_COLUMNS
 where TABLE_NAME = 'YOUR_TABLE'

Answer 2

describe user2.flights;

Here user2 is database name and flights is table name. Try this.

Or use next query

select *
  from user_tab_columns
 where table_name = 'MY_TABLE'
 order by column_id;  

Use this query.

column_id is the "order" of the column in the table.

You should ensure that ' MY_TABLE ' is capitalised unless you've been adding tables with casing ( a bad idea ) in which case you need to use something like = "MyTable"

Answer 3

DESC is a SQL*Plus command. SO, you cannot use it via JDBC/ODBC. An alternative can be like this below.

select RPAD(COLUMN_NAME,30)||' '||DATA_TYPE||'('||DATA_LENGTH||')' as descr
FROM all_tab_cols
  WHERE TABLE_NAME = UPPER('YOUR_TABLE') and owner=UPPER('SCHEMA_NAME');

all_tab_cols is a data dictionary table (view) which contains the table metadata

Oracle's Reference