dbpgsql.c

bonddb 是一个源于PostgreSQL封装包的对象。它是一个由C/C++编写的快速数据提取层应用软件

#include <glib.h>

#include "dbwrapper.h"

#ifdef _PGSQL

#include "dbpgsql.h"
#include "debug.h"
#include "dbuniqueid.h"
#include "dbsqlparse.h"

/*===========================================================================================
 * Connection based functions.
 *===========================================================================================
 */

/**
 * db_dbconnect:
 * @initstring: Postgresql initilising string
 * 
 * Direct wrapper for PQconnectdb(@initstring).  
 *
 * Returns: Connection to database.
 */
DbConnection *
db_dbconnect(gchar * initstring)
   {
   DbConnection *ret;

   g_assert(initstring);
   ret = (DbConnection *) mem_alloc(sizeof(DbConnection));
   ret->connstring = mem_strdup(initstring);
   ret->conn = PQconnectdb(initstring);
   ret->dbserver = DB_PGSQL;
   return ret;
   }

/**
 * db_dbstatus:
 * @conn: Database Connection
 * 
 * Direct wrapper for PQstatus(@conn).  
 *
 * Returns: status, a non-zero on failure
 */
gint
db_dbstatus(DbConnection * conn)
   {
   g_assert(conn);
   if (PQstatus(conn->conn) == CONNECTION_BAD)
      return 1;
   return 0;
   }

/**
 * db_dberrormsg:
 * @conn: Database Connection
 * 
 * Direct wrapper for PQerrormsg(@conn).  
 *
 * Returns: gchar* not to be freed.
 */
gchar *
db_dberrormsg(DbConnection * conn)
   {
   g_assert(conn);
   return PQerrorMessage(conn->conn);
   }

/**
 * db_dbfinish:
 * @conn: Database Connection
 * 
 * Direct wrapper for PQfinish(@conn).
 */
void
db_dbfinish(DbConnection * conn)
   {
   g_assert(conn);
   PQfinish(conn->conn);
   mem_free(conn->connstring);
   mem_free(conn);
   }

/**
 * db_dbreset:
 * @conn: Database Connection
 * 
 * Direct wrapper for PQreset(@conn).  This function is not essential and i dont think it is 
 * even called anywhere. So no need to make use of it.
 */
void
db_dbreset(DbConnection * conn)
   {
   g_assert(conn);
   PQreset(conn->conn);
   }

/*===========================================================================================
 * Result based functions.
 *===========================================================================================
 */

/**
 * db_dbcheckresult:
 * @result: Query result
 * 
 * Checks if any errors occured when running a query to postgresql, and if so return the
 * print the error messages and free any associated objects.
 *
 * Possibly a wrapper for PQresultStatus
 * 
 * Returns: non-zero on error
 */
gint
db_dbcheckresult(DbRecordSet * result)
   {
   int err;

   g_assert(result);
   if (result == NULL)
      {
      errormsg("Result is NULL");
      return -1;
      }
   if (result->res == NULL)
      {
      mem_free(result);
      errormsg("Result->res is NULL");
      return -3;
      }
   err = PQresultStatus(result->res);
   if (err == PGRES_BAD_RESPONSE || err == PGRES_NONFATAL_ERROR || err == PGRES_FATAL_ERROR)
      {
      errormsg("Result failed with %s", PQresultErrorMessage(result->res));
      errormsg("Query was %s",result->query);
	 /* Please note: people put dumb stuff into db programs. If we kill the app
	  * every time they do, it's gonna suck.  Badly. So don't!*/
	 /* I'm putting this in again to do some crazy testing. */
     /* g_assert(NULL);  */

      db_dbclear(result);
      result->res = NULL;
      return -2;
      }
   return 0;
   }

/**
 * db_dbclear:
 * @result: Query result
 * 
 * Direct wrapper for PQclear(@result).
 */
void
db_dbclear(DbRecordSet * result)
   {
   if (result == NULL)
      return ;
   PQclear(result->res);
   mem_free(result->query);
   if (result->basetable != NULL)
      mem_free(result->basetable);
   mem_free(result);
   result = NULL;
   }

/**
 * db_dbexec:
 * @conn: Database connection
 * @query: Query string
 * 
 * Direct wrapper for PQexec(@conn, @query).
 *
 * Returns: DbRecordSet to database.
 */
DbRecordSet *
db_dbexec(DbConnection * conn, gchar * query)
   {
   DbRecordSet *result;

   g_assert(conn);
   g_assert(query);
   result = (DbRecordSet *) mem_alloc(sizeof(DbRecordSet));
   result->query = mem_strdup(query);
   result->res = PQexec(conn->conn, query);
   /* Francis: Added the query result check */
   if (!result->res) {
	   errormsg ("According to postgresql documentation NULL value return for PQexec is a fatal error:\n%s\n", PQerrorMessage(conn->conn));
	   g_assert (0);
   }

	
   /* debugmsg("Adding query %s",result->query); */
   result->basetable = NULL;

   return result;
   }

/**
 * db_dbnumrows:
 * @result: Result from query
 * 
 * Direct wrapper for db_dbnumrows(@result);.
 *
 * Returns: Number of rows.
 */
gint
db_dbnumrows(DbRecordSet * result)
   {
   g_assert(result);
   g_assert(result->res);
   return PQntuples(result->res);
   }

/**
 * db_dbgetvalue:
 * @result: Result from query
 * @row: Position in recordset
 * @field: Field position
 * 
 * Direct wrapper for PQgetvalue(@result, @row, @field);.
 *
 * Returns: String of field
 */
gchar *
db_dbgetvalue(DbRecordSet * result, gint row, gint field)
   {
	gchar *retval;
   retval = PQgetvalue(result->res, row, field);
	if (strlen(retval)==0)
		return NULL;
	return retval;
   }

/**
 * db_dbnumfields:
 * @result: Result from a query
 * 
 * Direct wrapper for PQnfields(@result);.
 *
 * Returns: Number of fields in the @result.
 */
gint
db_dbnumfields(DbRecordSet * result)
   {
   g_assert(result);
   g_assert(result->res);
   return PQnfields(result->res);
   }

/**
 * db_dbfieldname:
 * @result: Result from a query
 * @fieldpos: Field position
 * 
 * Direct wrapper for PQfname(@result,@fieldpos);.
 *
 * Returns: Name of a field in recordset.
 */
gchar *
db_dbfieldname(DbRecordSet * result, gint fieldpos)
   {
   return PQfname(result->res, fieldpos);
   }

/**
 * db_dbuniqueid:
 * @result: Result from a insert
 * @fieldpos: Field position
 * 
 * Kinda a wrapper for PQoidValue(@result);
 * Assuming you run am insert query with db_dbexec(), this will return the unique id assocated with
 * that record.  Note this works on just getting the oid value from postgresql, on other databases
 * a bit of a work around will be needed.
 *
 * Returns: the pg OID value.
 */
gint
db_dbuniqueid(DbRecordSet * result)
   {
   gint oid;

   g_assert(result);
   g_assert(result->res);
   oid = PQoidValue(result->res);
   if (oid <= 0)
      return 0;
	if (result->basetable == NULL)
		errormsg("Unknown base table");
	return oid;
   }

#endif