ArcSDE C-API 开发：读取属性数据

<P>完整代码:</P>
<P >SE_CONNECTION       Connection;</P>
<P >SE_STREAM           Stream;</P>
<P >SE_SQL_CONSTRUCT   *sqlc</P>
<P >SE_ERROR            Connect_error;</P>
<P >LONG                rc, population;</P>
<P >SHORT               num_cols;</P>
<P >LFLOAT              area;</P>
<P >CHAR               *server, *instance, *database, *user, *passwd;</P>
<P >CHAR              **attrs, *name;</P>
<P > </P>
<P >/* Connect to ArcSDE */</P>
<P >rc = <a href="mk:@MSITStore:E:\应用软件\ArcSDE8.3\SDEHelp.chm::/CAPI_functions/functions/SE_connection_create.htm" target="_blank" >SE_connection_create</A></P>
<P >(server, instance, database, user, passwd, ;Connect_error,<BR>     ;Connection);</P>
<P >/* See Error handling section for check_error function code. */</P>
<P >check_error(Connection, NULL, rc, "SE_connection_create");</P>
<P > </P>
<P >/* Create a stream for the query */</P>
<P >rc = <a href="mk:@MSITStore:E:\应用软件\ArcSDE8.3\SDEHelp.chm::/CAPI_functions/functions/SE_stream_create.htm" target="_blank" >SE_stream_create</A> (Connection, ;Stream);</P>
<P >check_error(Connection, NULL, rc, "SE_stream_create");</P>
<P > </P>
<P >/* Allocate an SE_SQL_CONSTRUCT */</P>
<P >rc = <a href="mk:@MSITStore:E:\应用软件\ArcSDE8.3\SDEHelp.chm::/CAPI_functions/functions/SE_sql_construct_alloc.htm" target="_blank" >SE_sql_construct_alloc</A> (1, ;sqlc);</P>
<P >check_error(Connection, NULL, rc, "SE_sql_construct_alloc");</P>
<P > </P>
<P >/* Fill in the details of the SQL query */</P>
<P >sqlc->where = malloc(20);</P>
<P >sqlc->num_tables = 1;</P>
<P >strcpy (sqlc->tables[0], "cities");</P>
<P >strcpy (sqlc->where, "population < 10000");</P>
<P > </P>
<P >/* Define the number and names of the table columns to be returned */</P>
<P >num_cols = 3;</P>
<P >attrs = (CHAR **) malloc (num_cols * sizeof(CHAR *));</P>
<P >attrs[0] = "city_name";</P>
<P >attrs[1] = "area";</P>
<P >attrs[2] = "population";</P>
<P > </P>
<P >/* Define the stream query */</P>
<P >rc = <a href="mk:@MSITStore:E:\应用软件\ArcSDE8.3\SDEHelp.chm::/CAPI_functions/functions/SE_stream_query.htm" target="_blank" >SE_stream_query</A> (Stream, num_cols, attrs, sqlc);</P>
<P >check_error(NULL, Stream, rc, "SE_stream_query");</P>
<P > </P>
<P >rc = <a href="mk:@MSITStore:E:\应用软件\ArcSDE8.3\SDEHelp.chm::/CAPI_functions/functions/SE_stream_execute.htm" target="_blank" >SE_stream_execute</A> (Stream);</P>
<P >/* Iterate over the results */</P>
<P >while (rc == SE_SUCCESS)</P>
<P >{</P>
<P >   rc = <a href="mk:@MSITStore:E:\应用软件\ArcSDE8.3\SDEHelp.chm::/CAPI_functions/functions/SE_stream_fetch.htm" target="_blank" >SE_stream_fetch</A> (Stream);</P>
<P >   if (rc == SE_SUCCESS)</P>
<P >   {</P>
<P >     rc = SE_stream_get_string (Stream,1,name);</P>
<P >     check_error(NULL, Stream, rc, "SE_stream_get_string");</P>
<P > </P>
<P >     rc = <a href="mk:@MSITStore:E:\应用软件\ArcSDE8.3\SDEHelp.chm::/CAPI_functions/functions/SE_stream_get_double.htm" target="_blank" >SE_stream_get_double</A> (Stream,2,;area);</P>
<P >     check_error(NULL, Stream, rc, "SE_stream_get_double");</P>
<P > </P>
<P >     rc = <a href="mk:@MSITStore:E:\应用软件\ArcSDE8.3\SDEHelp.chm::/CAPI_functions/functions/SE_stream_get_double.htm" target="_blank" >SE_stream_get_integer</A> (Stream,3,;population);</P>
<P >     check_error(NULL, Stream, rc, "SE_stream_get_integer");</P>
<P > </P>
<P >     /* Now do something with the name, area and population */</P>
<P >   }</P>
<P >}</P>
<P > </P>
<P >/* Release the stream when it is no longer needed */</P>
<P >rc = <a href="mk:@MSITStore:E:\应用软件\ArcSDE8.3\SDEHelp.chm::/CAPI_functions/functions/SE_stream_free.htm" target="_blank" >SE_stream_free</A> (Stream);</P>
<P >free (attrs);</P>
<P >free (sqlc->where);</P>
<P ><a href="mk:@MSITStore:E:\应用软件\ArcSDE8.3\SDEHelp.chm::/CAPI_functions/functions/SE_sql_construct_free.htm" target="_blank" ><!--kadov_tag{{<spaces>}}--> <!--kadov_tag{{</spaces>}}-->SE_sql_construct_free</A> (sqlc);</P>
<P > </P>
<P >/* Disconnect from ArcSDE */</P>
<P ><a href="mk:@MSITStore:E:\应用软件\ArcSDE8.3\SDEHelp.chm::/CAPI_functions/functions/SE_connection_free.htm" target="_blank" ><!--kadov_tag{{<spaces>}}--> <!--kadov_tag{{</spaces>}}-->SE_connection_free</A> (Connection);</P>