prod/net/jaekl/cfb/db/driver/DbDriver.java

   1 package net.jaekl.cfb.db.driver;
   2
   3 // Copyright (C) 2015 Christian Jaekl
   4
   5 import static net.jaekl.cfb.db.Column.Null.*;
   6
   7 import java.sql.Connection;
   8 import java.sql.PreparedStatement;
   9 import java.sql.ResultSet;
  10 import java.sql.SQLException;
  11
  12 import net.jaekl.cfb.db.Column;
  13 import net.jaekl.cfb.db.Column.Type;
  14 import net.jaekl.cfb.db.Table;
  15
  16 public abstract class DbDriver {
  17         DbDriver() {
  18
  19         }
  20
  21         // Load the JDBC driver
  22         public abstract void load() throws ClassNotFoundException;
  23
  24         public abstract Connection connect(String host, int port, String dbName, String user, String pass) throws SQLException;
  25
  26         public boolean createTable(Connection con, Table table) throws SQLException {
  27                 String sql = createTableSql(table);
  28                 try (PreparedStatement ps = con.prepareStatement(sql)) {
  29                         ps.executeUpdate();
  30                 }
  31                 catch (SQLException exc) {
  32                         throw new SQLException("Failed to executeUpdate:  " + sql, exc);
  33                 }
  34
  35                 return true;
  36         }
  37
  38         public abstract ResultSet selectColumnsFromWhere(Column[] columns, Table[] tables, String where);
  39
  40         protected String typeName(Type type) {
  41                 return type.toString();
  42         }
  43
  44         protected String createColumnSql(Column column)
  45         {
  46                 String result = column.getName() + " " + typeName(column.getType());
  47                 if (column.getWidth() > 0) {
  48                         result += "(" + column.getWidth() + ")";
  49                 }
  50
  51                 if (NOT_NULL == column.getNull()) {
  52                         result += " NOT NULL";
  53                 }
  54                 else {
  55                         result += " NULL";
  56                 }
  57
  58                 return result;
  59         }
  60
  61         protected String createTableSql(Table table)
  62         {
  63                 assert(null != table);
  64                 assert(null != table.getName());
  65                 assert(table.getNumColumns() > 0);
  66
  67                 StringBuilder sb = new StringBuilder();
  68
  69                 sb.append("CREATE TABLE ")
  70                   .append(table.getName())
  71                   .append("(");
  72
  73                 for (int idx = 0; idx < table.getNumColumns(); ++idx) {
  74                         if (idx > 0) {
  75                                 sb.append(", ");
  76                         }
  77                         sb.append(createColumnSql(table.getColumn(idx)));
  78                 }
  79
  80                 sb.append(")");
  81
  82                 return sb.toString();
  83         }
  84 }