gensql.java

此程序都是企业级 的数据库开发程序 全面揭示了JAVA对数据库的操作

package metadata;

import java.util.*;
import java.sql.*;
import connections.*;

public class GenSql {
  public static void main(String args[]) {
    Connection conn = null;

    try {
      conn = ConnectionFactory.getConnection();
      DatabaseMetaData dbmd = conn.getMetaData();

      String[] tableTypes = new String[] {
        "TABLE"
      };
      ResultSet tables = dbmd.getTables(null, "APP", null, tableTypes);
      Vector vtables = new Vector();

      String aTable;

      // build up a list of tables
      while (tables.next()) {
        aTable = tables.getString("TABLE_NAME");
        vtables.add(aTable);
      } 

      ConnectionFactory.close(tables);

      Iterator iterator = vtables.iterator();

      // for each table in the list...
      String separator;
      while (iterator.hasNext()) {
        aTable = (String) iterator.next();

        // print the create table...
        System.out.print("create table " + aTable + " (");

        // print the columns
        ResultSet columns = dbmd.getColumns(null, null, aTable, null);
        separator = "";
        while (columns.next()) {
          String aColumn;

          System.out.print(separator);
          System.out.print(columns.getString("COLUMN_NAME"));

          int dataType = columns.getInt("DATA_TYPE");
          System.out.print(" " + columns.getString("TYPE_NAME"));

          if (dataType == java.sql.Types.CHAR 
                  || dataType == java.sql.Types.VARCHAR) {
            System.out.print("(" + columns.getString("COLUMN_SIZE") + ")");
          } 

          String isNullable = columns.getString("IS_NULLABLE");
          if (isNullable.equalsIgnoreCase("no")) {
            System.out.print(" NOT NULL");
          } 

          separator = ", ";
        } 

        // print the primary keys
        ResultSet pkeys = dbmd.getPrimaryKeys(null, null, aTable);
        String pkInfo = ", primary key(";

        separator = "";
        int pkCount = 0;
        while (pkeys.next()) {
          pkInfo = pkInfo.concat(separator 
                                 + pkeys.getString("COLUMN_NAME"));
          separator = ", ";
          pkCount++;
        } 
        pkInfo = pkInfo.concat(")");

        // if there were primary keys defined, add the pk statement
        if (pkCount > 0) {
          System.out.print(pkInfo);

        } 
        System.out.println(")\n");
      } 
    } catch (Exception e) {
      e.printStackTrace();
    } 
    finally {
      ConnectionFactory.close(conn);
    } 
  } 
}