statement.c

关系型数据库 Postgresql 6.5.2

/* Module:          statement.c
 *
 * Description:     This module contains functions related to creating
 *                  and manipulating a statement.
 *
 * Classes:         StatementClass (Functions prefix: "SC_")
 *
 * API functions:   SQLAllocStmt, SQLFreeStmt
 *
 * Comments:        See "notice.txt" for copyright and license information.
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "statement.h"
#include "bind.h"
#include "connection.h"
#include "qresult.h"
#include "convert.h"
#include "environ.h"
#include <stdio.h>
#include <string.h>

#ifndef WIN32
#include "iodbc.h"
#include "isql.h"
#else
#include <windows.h>
#include <sql.h>
#endif

extern GLOBAL_VALUES globals;

#ifndef WIN32
#ifndef HAVE_STRICMP
#define stricmp(s1,s2) 		strcasecmp(s1,s2)
#define strnicmp(s1,s2,n)	strncasecmp(s1,s2,n)
#endif
#endif

/*	Map sql commands to statement types */
static struct {
	int  type;
	char *s;
} Statement_Type[] = {
	{ STMT_TYPE_SELECT, "SELECT" },
	{ STMT_TYPE_INSERT, "INSERT" },
	{ STMT_TYPE_UPDATE, "UPDATE" },
	{ STMT_TYPE_DELETE, "DELETE" },
	{ STMT_TYPE_CREATE, "CREATE" },
	{ STMT_TYPE_ALTER,  "ALTER"  },
	{ STMT_TYPE_DROP,   "DROP"   },
	{ STMT_TYPE_GRANT,  "GRANT"  },
	{ STMT_TYPE_REVOKE, "REVOKE" },
	{      0,            NULL    }
};


RETCODE SQL_API SQLAllocStmt(HDBC      hdbc,
                             HSTMT FAR *phstmt)
{
static char *func="SQLAllocStmt";
ConnectionClass *conn = (ConnectionClass *) hdbc;
StatementClass *stmt;

	mylog("%s: entering...\n", func);

	if( ! conn) {
		CC_log_error(func, "", NULL);
		return SQL_INVALID_HANDLE;
	}

	stmt = SC_Constructor();

	mylog("**** SQLAllocStmt: hdbc = %u, stmt = %u\n", hdbc, stmt);

	if ( ! stmt) {
		conn->errornumber = CONN_STMT_ALLOC_ERROR;
		conn->errormsg = "No more memory to allocate a further SQL-statement";
		*phstmt = SQL_NULL_HSTMT;
		CC_log_error(func, "", conn);
		return SQL_ERROR;
	}

    if ( ! CC_add_statement(conn, stmt)) {
        conn->errormsg = "Maximum number of connections exceeded.";
        conn->errornumber = CONN_STMT_ALLOC_ERROR;
		CC_log_error(func, "", conn);
        SC_Destructor(stmt);
		*phstmt = SQL_NULL_HSTMT;
        return SQL_ERROR;
    }

	*phstmt = (HSTMT) stmt;

	/*	Copy default statement options based from Connection options
	*/
	stmt->options = conn->stmtOptions;


	/*	Save the handle for later */
	stmt->phstmt = phstmt;

    return SQL_SUCCESS;
}


RETCODE SQL_API SQLFreeStmt(HSTMT     hstmt,
                            UWORD     fOption)
{
static char *func="SQLFreeStmt";
StatementClass *stmt = (StatementClass *) hstmt;

	mylog("%s: entering...hstmt=%u, fOption=%d\n", func, hstmt, fOption);

	if ( ! stmt) {
		SC_log_error(func, "", NULL);
		return SQL_INVALID_HANDLE;
	}

	if (fOption == SQL_DROP) {
		ConnectionClass *conn = stmt->hdbc;

		/* Remove the statement from the connection's statement list */
		if ( conn) {
			if ( ! CC_remove_statement(conn, stmt)) {
				stmt->errornumber = STMT_SEQUENCE_ERROR;
				stmt->errormsg = "Statement is currently executing a transaction.";
				SC_log_error(func, "", stmt);
				return SQL_ERROR;  /* stmt may be executing a transaction */
			}

			/*	Free any cursors and discard any result info */
			if (stmt->result) {
				QR_Destructor(stmt->result);
				stmt->result = NULL;
			}
		}

		/* Destroy the statement and free any results, cursors, etc. */
		SC_Destructor(stmt);

    } else if (fOption == SQL_UNBIND) {
		SC_unbind_cols(stmt);

    } else if (fOption == SQL_CLOSE) {
		/* this should discard all the results, but leave the statement */
		/* itself in place (it can be executed again) */
        if (!SC_recycle_statement(stmt)) {
			//	errormsg passed in above
			SC_log_error(func, "", stmt);
            return SQL_ERROR;
		}

    } else if(fOption == SQL_RESET_PARAMS) {
		SC_free_params(stmt, STMT_FREE_PARAMS_ALL);

    } else {
        stmt->errormsg = "Invalid option passed to SQLFreeStmt.";
        stmt->errornumber = STMT_OPTION_OUT_OF_RANGE_ERROR;
		SC_log_error(func, "", stmt);
        return SQL_ERROR;
    }
    
    return SQL_SUCCESS;
}



/**********************************************************************
 * StatementClass implementation
 */
void
InitializeStatementOptions(StatementOptions *opt)
{
	opt->maxRows = 0;			// driver returns all rows
	opt->maxLength = 0;			// driver returns all data for char/binary
	opt->rowset_size = 1;
	opt->keyset_size = 0;		// fully keyset driven is the default
	opt->scroll_concurrency = SQL_CONCUR_READ_ONLY;
	opt->cursor_type = SQL_CURSOR_FORWARD_ONLY;
	opt->bind_size = 0;			/* default is to bind by column */
	opt->retrieve_data = SQL_RD_ON;
	opt->use_bookmarks = SQL_UB_OFF;
}

StatementClass *
SC_Constructor(void)
{
StatementClass *rv;

	rv = (StatementClass *) malloc(sizeof(StatementClass));
	if (rv) {
		rv->hdbc = NULL;       /* no connection associated yet */
		rv->phstmt = NULL;
		rv->result = NULL;
		rv->manual_result = FALSE;
		rv->prepare = FALSE;
		rv->status = STMT_ALLOCATED;
		rv->internal = FALSE;

		rv->errormsg = NULL;
		rv->errornumber = 0;
		rv->errormsg_created = FALSE;

		rv->statement = NULL;
		rv->stmt_with_params[0] = '\0';
		rv->statement_type = STMT_TYPE_UNKNOWN;

		rv->bindings = NULL;
		rv->bindings_allocated = 0;

		rv->bookmark.buffer = NULL;
		rv->bookmark.used = NULL;

		rv->parameters_allocated = 0;
		rv->parameters = 0;

		rv->currTuple = -1;
		rv->rowset_start = -1;
		rv->current_col = -1;
		rv->bind_row = 0;
		rv->last_fetch_count = 0;
		rv->save_rowset_size = -1;

		rv->data_at_exec = -1;
		rv->current_exec_param = -1;
		rv->put_data = FALSE;

		rv->lobj_fd = -1;
		rv->cursor_name[0] = '\0';

		/*	Parse Stuff */
		rv->ti = NULL;
		rv->fi = NULL;
		rv->ntab = 0;
		rv->nfld = 0;
		rv->parse_status = STMT_PARSE_NONE;


		/*  Clear Statement Options -- defaults will be set in AllocStmt */
		memset(&rv->options, 0, sizeof(StatementOptions));
	}
	return rv;
}

char
SC_Destructor(StatementClass *self)
{

	mylog("SC_Destructor: self=%u, self->result=%u, self->hdbc=%u\n", self, self->result, self->hdbc);
	if (STMT_EXECUTING == self->status) {
		self->errornumber = STMT_SEQUENCE_ERROR;
		self->errormsg = "Statement is currently executing a transaction.";
		return FALSE;
	}

	if (self->result) {
		if ( ! self->hdbc)
			self->result->conn = NULL;  /* prevent any dbase activity */

		QR_Destructor(self->result);
	}

	if (self->statement)
		free(self->statement);

	SC_free_params(self, STMT_FREE_PARAMS_ALL);

	/* the memory pointed to by the bindings is not deallocated by the driver */
	/* by by the application that uses that driver, so we don't have to care  */
	/* about that here. */
	if (self->bindings)
		free(self->bindings);


	/*	Free the parsed table information */
	if (self->ti) {
		int i;
		for (i = 0; i < self->ntab; i++) {
			free(self->ti[i]);
		}

		free(self->ti);
	}

	/*	Free the parsed field information */
	if (self->fi) {
		int i;
		for (i = 0; i < self->nfld; i++) {
			free(self->fi[i]);
		}
		free(self->fi);
	}


	free(self);

	mylog("SC_Destructor: EXIT\n");

	return TRUE;
}

/*	Free parameters and free the memory from the 
	data-at-execution parameters that was allocated in SQLPutData.
*/
void
SC_free_params(StatementClass *self, char option)
{
int i;

	mylog("SC_free_params:  ENTER, self=%d\n", self);

	if( ! self->parameters)
		return;

	for (i = 0; i < self->parameters_allocated; i++) {
		if (self->parameters[i].data_at_exec == TRUE) {

			if (self->parameters[i].EXEC_used) {
				free(self->parameters[i].EXEC_used);
				self->parameters[i].EXEC_used = NULL;
			}

			if (self->parameters[i].EXEC_buffer) {
				free(self->parameters[i].EXEC_buffer);
				self->parameters[i].EXEC_buffer = NULL;
			}
		}
	}
	self->data_at_exec = -1;
	self->current_exec_param = -1;
	self->put_data = FALSE;

	if (option == STMT_FREE_PARAMS_ALL) {
		free(self->parameters);
		self->parameters = NULL;
		self->parameters_allocated = 0;
	}

	mylog("SC_free_params:  EXIT\n");
}


int 
statement_type(char *statement)
{
int i;

	for (i = 0; Statement_Type[i].s; i++)
		if ( ! strnicmp(statement, Statement_Type[i].s, strlen(Statement_Type[i].s)))
			return Statement_Type[i].type;

	return STMT_TYPE_OTHER;
}


/*	Called from SQLPrepare if STMT_PREMATURE, or
	from SQLExecute if STMT_FINISHED, or
	from SQLFreeStmt(SQL_CLOSE)
 */
char 
SC_recycle_statement(StatementClass *self)
{
ConnectionClass *conn;

mylog("recycle statement: self= %u\n", self);

	/*	This would not happen */    
	if (self->status == STMT_EXECUTING) {
		self->errornumber = STMT_SEQUENCE_ERROR;
		self->errormsg = "Statement is currently executing a transaction.";
		return FALSE;
	}

	self->errormsg = NULL;
	self->errornumber = 0;
	self->errormsg_created = FALSE;

	switch (self->status) {
	case STMT_ALLOCATED:
		/* this statement does not need to be recycled */
		return TRUE;

	case STMT_READY:
		break;

	case STMT_PREMATURE:
		/*	Premature execution of the statement might have caused the start of a transaction.
			If so, we have to rollback that transaction.
		*/
		conn = SC_get_conn(self);
		if ( ! CC_is_in_autocommit(conn) && CC_is_in_trans(conn)) {             

			CC_send_query(conn, "ABORT", NULL);
			CC_set_no_trans(conn);
		}
		break;

	case STMT_FINISHED:
		break;

	default:
		self->errormsg = "An internal error occured while recycling statements";
		self->errornumber = STMT_INTERNAL_ERROR;
		return FALSE;
	}

	/*	Free the parsed table information */
	if (self->ti) {
		int i;
		for (i = 0; i < self->ntab; i++) {
			free(self->ti[i]);
		}

		free(self->ti);
		self->ti = NULL;
		self->ntab = 0;
	}

	/*	Free the parsed field information */
	if (self->fi) {
		int i;
		for (i = 0; i < self->nfld; i++) {
			free(self->fi[i]);
		}
		free(self->fi);
		self->fi = NULL;
		self->nfld = 0;
	}
	self->parse_status = STMT_PARSE_NONE;

	/*	Free any cursors */
	if (self->result) {
		QR_Destructor(self->result);
		self->result = NULL;
	}

	/****************************************************************/
	/*	Reset only parameters that have anything to do with results */
	/****************************************************************/

	self->status = STMT_READY;
	self->manual_result = FALSE;	// very important

	self->currTuple = -1;
	self->rowset_start = -1;
	self->current_col = -1;
	self->bind_row = 0;
	self->last_fetch_count = 0;

	self->errormsg = NULL;
	self->errornumber = 0;
	self->errormsg_created = FALSE;

	self->lobj_fd = -1;

	//	Free any data at exec params before the statement is executed
	//	again.  If not, then there will be a memory leak when
	//	the next SQLParamData/SQLPutData is called.
	SC_free_params(self, STMT_FREE_PARAMS_DATA_AT_EXEC_ONLY);

	return TRUE;