Re: Re: What needs to be done?

Поиск
Список
Период
Сортировка
От Ricardo Maia
Тема Re: Re: What needs to be done?
Дата
Msg-id 01080211514900.24503@valkyrie
обсуждение исходный текст
Ответ на Re: What needs to be done?  (Barry Lind <barry@xythos.com>)
Список pgsql-jdbc

So how whould I map the BLOB java type in the corresponding SQL type?

I want to create a table with a BLOB attribute, but I want that my code can
run for PostgreSQL, Oracle and other BD that handles BLOBs.

So first I had to map the BLOB in the corresponding BD SQL type and then
create the table with an attribute of that SQL type.

Ricardo Maia

On Thursday 02 August 2001 03:16, Barry Lind wrote:
> I actually think the response for 'oid' is correct.  It reports the oid
> as java type integer (which is the real datatype of the value stored).
> A column of type oid can be used for may different things.  It can be
> used for blobs, but not all columns of type oid are used for blobs.
> Another use of a column of type oid is to store foreign keys from one
> table to another.  Since all tables have a builtin column named 'oid' of
> type oid, it is very convenient to use this value in foreign keys on
> other tables.  Assuming that oid = blob would break those applications.
>
> I hope everyone that uses postgresql and jdbc understands that BLOB
> support is one area with many problems, some of which can be fixed in
> the JDBC code, but others that will require better support in the
> underlying database.
>
> thanks,
> --Barry
>
> Ricardo Maia wrote:
> > For example when I call the method:
> >
> > DatabaseMetaData.getTypeInfo()
> >
> > I whould expect to see the SQL Type BLOB mapped as an oid.
> >
> > see attach
> >
> > Ricardo Maia
> >
> > On Wednesday 01 August 2001 23:29, Rene Pijlman wrote:
> >>On Wed, 1 Aug 2001 22:49:40 +0100, Ricardo Maia wrote:
> >>>The problem is that, as the PostgreSQL JDBC driver doesn't
> >>>follow JDBC Standard I had to write some specific code for
> >>>use it with PostgreSQL DB.
> >>
> >>So what exactly are the deviations from the standard that you
> >>encountered?
> >>
> >>Regards,
> >>René Pijlman
> >>
> >>---------------------------(end of broadcast)---------------------------
> >>TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org
> >>
> >>
> >>------------------------------------------------------------------------
> >>
> >>package databasetest;
> >>
> >>import java.sql.*;
> >>
> >>public class GetTypesInfo {
> >>
> >>  public static void main(String args[ ]) {
> >>
> >>    String url = "jdbc:postgresql://127.0.0.1/test";
> >>
> >>    Connection con;
> >>
> >>    DatabaseMetaData dbmd;
> >>
> >>    try {
> >>      Class.forName("org.postgresql.Driver");
> >>    } catch(java.lang.ClassNotFoundException e) {
> >>      System.err.print("ClassNotFoundException: ");
> >>      System.err.println(e.getMessage());
> >>    }
> >>
> >>    try {
> >>      con = DriverManager.getConnection(url,"bobby", "tareco");
> >>
> >>      dbmd = con.getMetaData();
> >>
> >>      ResultSet rs = dbmd.getTypeInfo();
> >>
> >>      while (rs.next()) {
> >>
> >>        String typeName = rs.getString("TYPE_NAME");
> >>
> >>        short dataType = rs.getShort("DATA_TYPE");
> >>
> >>        String createParams = rs.getString("CREATE_PARAMS");
> >>
> >>        int nullable = rs.getInt("NULLABLE");
> >>
> >>        boolean caseSensitive = rs.getBoolean("CASE_SENSITIVE");
> >>
> >>        if(dataType != java.sql.Types.OTHER)
> >>        {
> >>          System.out.println("DBMS type " + typeName + ":");
> >>          System.out.println("     java.sql.Types:  "  +
> >> typeName(dataType)); System.out.print("     parameters used to create:
> >> ");
> >>          System.out.println(createParams);
> >>          System.out.println("     nullable?:  "  + nullable);
> >>          System.out.print("     case sensitive?:  ");
> >>          System.out.println(caseSensitive);
> >>          System.out.println("");
> >>        }
> >>      }
> >>
> >>      con.close();
> >>    } catch(SQLException ex) {
> >>      System.err.println("SQLException: " + ex.getMessage());
> >>    }
> >>  }
> >>
> >>
> >>  public static String typeName(int i)
> >>  {
> >>    switch(i){
> >>      case java.sql.Types.ARRAY: return "ARRAY";
> >>      case java.sql.Types.BIGINT: return "BIGINT";
> >>      case java.sql.Types.BINARY: return "BINARY";
> >>      case java.sql.Types.BIT: return "BIT";
> >>      case java.sql.Types.BLOB: return "BLOB";
> >>      case java.sql.Types.CHAR: return "CHAR";
> >>      case java.sql.Types.CLOB: return "CLOB";
> >>      case java.sql.Types.DATE: return "DATE";
> >>      case java.sql.Types.DECIMAL: return "DECIMAL";
> >>      case java.sql.Types.DISTINCT: return "DISTINCT";
> >>      case java.sql.Types.DOUBLE: return "DOUBLE";
> >>      case java.sql.Types.FLOAT: return "FLOAT";
> >>      case java.sql.Types.INTEGER: return "INTEGER";
> >>      case java.sql.Types.JAVA_OBJECT: return "JAVA_OBJECT";
> >>      case java.sql.Types.LONGVARBINARY: return "LONGVARBINARY";
> >>      case java.sql.Types.LONGVARCHAR: return "LONGVARCHAR";
> >>      case java.sql.Types.NULL: return "NULL";
> >>      case java.sql.Types.NUMERIC: return "NUMERIC";
> >>      case java.sql.Types.OTHER: return "OTHER";
> >>      case java.sql.Types.REAL: return "REAL";
> >>      case java.sql.Types.REF: return "REF";
> >>      case java.sql.Types.SMALLINT: return "SMALLINT";
> >>      case java.sql.Types.STRUCT: return "STRUCT";
> >>      case java.sql.Types.TIME: return "TIME";
> >>      case java.sql.Types.TIMESTAMP: return "TIMESTAMP";
> >>      case java.sql.Types.TINYINT: return "TINYINT";
> >>      case java.sql.Types.VARBINARY: return "VARBINARY";
> >>      case java.sql.Types.VARCHAR: return "VARCHAR";
> >>      default: return "";
> >>    }
> >>  }
> >>}
> >>
> >>
> >>------------------------------------------------------------------------
> >>
> >>
> >>---------------------------(end of broadcast)---------------------------
> >>TIP 5: Have you checked our extensive FAQ?
> >>
> >>http://www.postgresql.org/users-lounge/docs/faq.html
> >>
> >> GetTypesInfo.java
> >>
> >> Content-Type:
> >>
> >> text/x-java
> >> Content-Encoding:
> >>
> >> base64
> >>
> >>
> >> ------------------------------------------------------------------------
> >> Part 1.3
> >>
> >> Content-Type:
> >>
> >> text/plain
> >> Content-Encoding:
> >>
> >> binary
>
> ---------------------------(end of broadcast)---------------------------
> TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org

В списке pgsql-jdbc по дате отправления:

Предыдущее
От: "Joe Shevland"
Дата:
Сообщение: RE: Patch to improve commit time performance and a few other things
Следующее
От: "Stephen J. Thompson"
Дата:
Сообщение: JDBC and blobs