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Interface de bas niveau du serveur Oracle

L'interface de bas niveau du serveur Oracle existe d'une unité, oraoci, qui est une traduction directe des fichiers d'en-tête de l'interface d'Oracle.

Il y a deux programmes exemples :

• oraclew contient quelques routines utilitaire pour l'interface Oracle, pour une gestion plus facile des ensembles résultats. Nécessite l'unité Classes de la FCL.
• test01 un simple programmme de test pour montrer l'interface.

Accès direct à Oracle

You can directly connect Lazarus and Oracle by using Oracle Data Access Components (ODAC). It is a library of components that provides native connectivity to Oracle from Lazarus (and Free Pascal) on Windows, Mac OS X, iOS, Android, Linux, and FreeBSD for both 32-bit and 64-bit platforms. The ODAC library is designed to help programmers develop faster and more native Oracle database applications.

This Lazarus component is free to download.

Accès POO à Oracle

Built over the low-level interface, the SQLDB framework supplied with FPC supports accessing Oracle (using TOracleConnection); see also Lazarus_Database_Overview#Lazarus_and_Oracle

Lazarus also has a component: TOracleConnection

• Hostname: as with other sqldb connectors, use hostname or IP address. Leave empty if you use a TNSNAMES.ORA net service name in DatabaseName
• Username/password: same as with other sqldb connectors
• DatabaseName:
  • instance/SID of the Oracle server you want to connect to or
  • net service name in a TNSNAMES.ORA file

  Remarque: Released FPC/Lazarus x64 versions on Windows do not include an Oracle connector. If you enable it and test successfully, please submit a patch with the changes so it can be included

Résolution de problèmes

Jeu de caractères Client et serveur

To get info about what character set/NLS settings are active, you can run the following program.

Please don't forget to fill out correct server name, username, password and database name before compiling.

program oracharset;

{ Shows client and server character set/NLS info}
{ PLEASE EDIT PASSWORDS ETC BELOW. }

{$mode objfpc}{$H+}

uses {$IFDEF UNIX} {$IFDEF UseCThreads}
  cthreads, {$ENDIF} {$ENDIF}
  Classes,
  SysUtils,
  sqldb,
  oracleconnection;

var
  Col: integer;
  Conn: TOracleConnection;
  Tran: TSQLTransaction;
  Q: TSQLQuery;
begin
  Conn := TOracleConnection.Create(nil);
  Tran := TSQLTransaction.Create(nil);
  Q := TSQLQuery.Create(nil);
  try
    // * EDIT IDENTIFYING INFO AS NEEDED*
    Conn.HostName := '';
    Conn.UserName := 'system';
    Conn.Password := '';
    Conn.DatabaseName := 'XE';
    // *END IDENTIFIYING INFO*
    Conn.Transaction := Tran;
    Q.DataBase := Conn;
    Conn.Open;
    Tran.Active := true;

    writeln('Server character set info:');
    Q.SQL.Text := 'SELECT value$ FROM sys.props$ WHERE name like ''NLS_%'' ';
    Q.Open;
    Q.First;
    while not (Q.EOF) do
    begin
      writeln('*****************');
      for Col := 0 to Q.Fields.Count - 1 do
      begin
        try
          writeln(Q.Fields[Col].DisplayLabel + ':');
          writeln(Q.Fields[Col].AsString);
        except
          writeln('Error retrieving field ', Col);
        end;
      end;
      Q.Next;
    end;
    Q.Close;

    writeln('');
    writeln('Client character set info:');
    Q.SQL.Text := 'SELECT * FROM NLS_SESSION_PARAMETERS ';
    Q.Open;
    Q.First;
    while not (Q.EOF) do
    begin
      writeln('*****************');
      for Col := 0 to Q.Fields.Count - 1 do
      begin
        try
          writeln(Q.Fields[Col].DisplayLabel + ':');
          writeln(Q.Fields[Col].AsString);
        except
          writeln('Error retrieving field ', Col);
        end;
      end;
      Q.Next;
    end;
    Q.Close;
    // *END EXAMPLE BUG TESTING CODE*
    Conn.Close;
  finally
    Q.Free;
    Tran.Free;
    Conn.Free;
  end;
  writeln('Program complete. Press a key to continue.');
  readln;
end.

ORA-00911 : invalid character

If you see this error message, you might want to try

• removing a trailing semicolon - ; - if you have it in a SELECT statement
• adding a trailing semicolon (e.g. in CALL or EXECUTE statements)

See this thread which applies to .Net but may apply to SQLDB as well: [1]

Revenir vers Liste des paquets.