看看zabbix 数据库操作结构体

struct zbx_db_result

{

#if defined(HAVE_IBM_DB2)

SQLHANDLE hstmt;

SQLSMALLINT nalloc;

SQLSMALLINT ncolumn;

DB_ROW values;

DB_ROW values_cli;

SQLINTEGER *values_len;

#elif defined(HAVE_MYSQL)

#elif defined(HAVE_ORACLE)

OCIStmt *stmthp; /* the statement handle for select operations */

int ncolumn;

DB_ROW values;

ub4 *values_alloc;

OCILobLocator **clobs;

#elif defined(HAVE_POSTGRESQL)

PGresult *pg_result;

int row_num;

int fld_num;

int cursor;

DB_ROW values;

#elif defined(HAVE_SQLITE3)

int curow;

char **data;

int nrow;

int ncolumn;

DB_ROW values;

#endif

};

/******************************************************************************

* *

* Function: DBselect *

* *

* Purpose: execute a select statement *

* *

* Comments: retry until DB is up *

* *

******************************************************************************/

DB_RESULT __zbx_DBselect(const char *fmt, ...)

{

va_list args; //参数列表

DB_RESULT rc;

va_start(args, fmt);

rc = zbx_db_vselect(fmt, args);

while ((DB_RESULT)ZBX_DB_DOWN == rc)

{

DBclose();

DBconnect(ZBX_DB_CONNECT_NORMAL);

if ((DB_RESULT)ZBX_DB_DOWN == (rc = zbx_db_vselect(fmt, args)))

{

zabbix_log(LOG_LEVEL_ERR, "database is down: retrying in %d seconds", ZBX_DB_WAIT_DOWN);

connection_failure = 1;

sleep(ZBX_DB_WAIT_DOWN);

}

}

va_end(args);

return rc;

}

typedef struct st_mysql_res {

my_ulonglong row_count;

MYSQL_FIELD *fields;

MYSQL_DATA *data;

MYSQL_ROWS *data_cursor;

unsigned long *lengths; /* column lengths of current row */

MYSQL *handle; /* for unbuffered reads */

const struct st_mysql_methods *methods;

MYSQL_ROW row; /* If unbuffered read */

MYSQL_ROW current_row; /* buffer to current row */

MEM_ROOT field_alloc;

unsigned int field_count, current_field;

my_bool eof; /* Used by mysql_fetch_row */

/* mysql_stmt_close() had to cancel this result */

my_bool unbuffered_fetch_cancelled;

void *extension;

} MYSQL_RES;