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I have a desktop application with a database embedded in it. When I execute my program I need to check that specific table exists, or create it if not.
Given a Connection object named conn for my database, how could I check this?
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The go to solution for removing duplicate rows from your result sets is to include the distinct keyword in your select statement. It tells the query engine to remove duplicates to produce a result set in which every row is unique.
Check for Duplicates in Multiple Tables With INNER JOINUse the INNER JOIN function to find duplicates that exist in multiple tables. Sample syntax for an INNER JOIN function looks like this: SELECT column_name FROM table1 INNER JOIN table2 ON table1. column_name = table2.
DatabaseMetaData dbm = con.getMetaData(); // check if "employee" table is there ResultSet tables = dbm.getTables(null, null, "employee", null); if (tables.next()) { // Table exists } else { // Table does not exist } You can use the available meta data:
DatabaseMetaData meta = con.getMetaData(); ResultSet res = meta.getTables(null, null, "My_Table_Name", new String[] {"TABLE"}); while (res.next()) { System.out.println( " "+res.getString("TABLE_CAT") + ", "+res.getString("TABLE_SCHEM") + ", "+res.getString("TABLE_NAME") + ", "+res.getString("TABLE_TYPE") + ", "+res.getString("REMARKS")); } See here for more details. Note also the caveats in the JavaDoc.
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