Question

I’ve been trying to retrieve constraint data for all tables using an SQL query over JDBC.

My test database has only 3 tables.

If I execute the query interactively using MS SQL Server Management Studio, I get all the results that I expect (ie. 3 rows – there’s a primary key in each of 3 tables).

if I use the JDBC method to specifically retrieve primary keys (as below) then I also correctly get 3 results:

ResultSet rs = dbmd.getPrimaryKeys(jdbcCatalog, jdbcSchema, jdbcTableName);

If I use the exact same SQL statement (that I used interactively and got 3 results back) as a query over JDBC (using executeQuery() shown below) then I only get 1 result instead of the expected 3.

String query =
    "select PK.CONSTRAINT_NAME, PK.TABLE_SCHEMA, PK.TABLE_NAME " +
    "from information_schema.TABLE_CONSTRAINTS PK";
ResultSet rs = null;
try {
    Statement stmt = con.createStatement();
    rs = stmt.executeQuery(query);
}catch (Exception exception) {
    // Exception handler code
}
while (rs.next()){
    // Only executes once.
}

I would be very grateful if someone could explain why the SQL query over JDBC is performing differently to the exact same SQL query performed interactively. Could it be a security/ownership issue? (although the JDBC call getPrimaryKeys() doesn’t suffer this)
Thanks.

Answer 1

I don’t see where you’re setting your database context, but I suspect that that’s the issue. As a test, you can change your statement to “select db_name()” and see what it returns. If it’s not the database that you think that you should be in, that’s your issue.