SQLBindCol Function

Článek
02/28/2023

Conformance
Version Introduced: ODBC 1.0 Standards Compliance: ISO 92

Summary
SQLBindCol binds application data buffers to columns in the result set.

Syntax

  
SQLRETURN SQLBindCol(  
      SQLHSTMT       StatementHandle,  
      SQLUSMALLINT   ColumnNumber,  
      SQLSMALLINT    TargetType,  
      SQLPOINTER     TargetValuePtr,  
      SQLLEN         BufferLength,  
      SQLLEN *       StrLen_or_IndPtr);

Arguments

StatementHandle
[Input] Statement handle.

ColumnNumber
[Input] Number of the result set column to bind. Columns are numbered in increasing column order starting at 0, where column 0 is the bookmark column. If bookmarks are not used - that is, the SQL_ATTR_USE_BOOKMARKS statement attribute is set to SQL_UB_OFF - then column numbers start at 1.

TargetType
[Input] The identifier of the C data type of the *TargetValuePtr buffer. When it is retrieving data from the data source with SQLFetch, SQLFetchScroll, SQLBulkOperations, or SQLSetPos, the driver converts the data to this type; when it sends data to the data source with SQLBulkOperations or SQLSetPos, the driver converts the data from this type. For a list of valid C data types and type identifiers, see the C Data Types section in Appendix D: Data Types.

If the TargetType argument is an interval data type, the default interval leading precision (2) and the default interval seconds precision (6), as set in the SQL_DESC_DATETIME_INTERVAL_PRECISION and SQL_DESC_PRECISION fields of the ARD, respectively, are used for the data. If the TargetType argument is SQL_C_NUMERIC, the default precision (driver-defined) and default scale (0), as set in the SQL_DESC_PRECISION and SQL_DESC_SCALE fields of the ARD, are used for the data. If any default precision or scale is not appropriate, the application should explicitly set the appropriate descriptor field by a call to SQLSetDescField or SQLSetDescRec.

You can also specify an extended C data type. For more information, see C Data Types in ODBC.

TargetValuePtr
[Deferred Input/Output] Pointer to the data buffer to bind to the column. SQLFetch and SQLFetchScroll return data in this buffer. SQLBulkOperations returns data in this buffer when Operation is SQL_FETCH_BY_BOOKMARK; it retrieves data from this buffer when Operation is SQL_ADD or SQL_UPDATE_BY_BOOKMARK. SQLSetPos returns data in this buffer when Operation is SQL_REFRESH; it retrieves data from this buffer when Operation is SQL_UPDATE.

If TargetValuePtr is a null pointer, the driver unbinds the data buffer for the column. An application can unbind all columns by calling SQLFreeStmt with the SQL_UNBIND option. An application can unbind the data buffer for a column but still have a length/indicator buffer bound for the column, if the TargetValuePtr argument in the call to SQLBindCol is a null pointer but the StrLen_or_IndPtr argument is a valid value.

BufferLength
[Input] Length of the *TargetValuePtr buffer in bytes.

The driver uses BufferLength to avoid writing past the end of the *TargetValuePtr buffer when it returns variable-length data, such as character or binary data. Notice that the driver counts the null-termination character when it returns character data to *TargetValuePtr. *TargetValuePtr must therefore contain space for the null-termination character or the driver will truncate the data.

When the driver returns fixed-length data, such as an integer or a date structure, the driver ignores BufferLength and assumes the buffer is large enough to hold the data. Therefore, it is important for the application to allocate a large enough buffer for fixed-length data or the driver will write past the end of the buffer.

SQLBindCol returns SQLSTATE HY090 (Invalid string or buffer length) when BufferLength is less than 0 but not when BufferLength is 0. However, if TargetType specifies a character type, an application should not set BufferLength to 0, because ISO CLI-compliant drivers return SQLSTATE HY090 (Invalid string or buffer length) in that case.

StrLen_or_IndPtr
[Deferred Input/Output] Pointer to the length/indicator buffer to bind to the column. SQLFetch and SQLFetchScroll return a value in this buffer. SQLBulkOperations retrieves a value from this buffer when Operation is SQL_ADD, SQL_UPDATE_BY_BOOKMARK, or SQL_DELETE_BY_BOOKMARK. SQLBulkOperations returns a value in this buffer when Operation is SQL_FETCH_BY_BOOKMARK. SQLSetPos returns a value in this buffer when Operation is SQL_REFRESH; it retrieves a value from this buffer when Operation is SQL_UPDATE.

SQLFetch, SQLFetchScroll, SQLBulkOperations, and SQLSetPos can return the following values in the length/indicator buffer:

The length of the data available to return
SQL_NO_TOTAL
SQL_NULL_DATA

The application can put the following values in the length/indicator buffer for use with SQLBulkOperations or SQLSetPos:

The length of the data being sent
SQL_NTS
SQL_NULL_DATA
SQL_DATA_AT_EXEC
The result of the SQL_LEN_DATA_AT_EXEC macro
SQL_COLUMN_IGNORE

If the indicator buffer and the length buffer are separate buffers, the indicator buffer can return only SQL_NULL_DATA, whereas the length buffer can return all other values.

For more information, see SQLBulkOperations Function, SQLFetch Function, SQLSetPos Function, and Using Length/Indicator Values.

If StrLen_or_IndPtr is a null pointer, no length or indicator value is used. This is an error when fetching data and the data is NULL.

See ODBC 64-Bit Information, if your application will run on a 64-bit operating system.

Returns

SQL_SUCCESS, SQL_SUCCESS_WITH_INFO, SQL_ERROR, or SQL_INVALID_HANDLE.

Diagnostics

When SQLBindCol returns SQL_ERROR or SQL_SUCCESS_WITH_INFO, an associated SQLSTATE value can be obtained by calling SQLGetDiagRec with a HandleType of SQL_HANDLE_STMT and a Handle of StatementHandle. The following table lists the SQLSTATE values typically returned by SQLBindCol and explains each one in the context of this function; the notation "(DM)" precedes the descriptions of SQLSTATEs returned by the Driver Manager. The return code associated with each SQLSTATE value is SQL_ERROR, unless noted otherwise.

SQLSTATE	Error	Description
01000	General warning	Driver-specific informational message. (Function returns SQL_SUCCESS_WITH_INFO.)
07006	Restricted data type attribute violation	(DM) The ColumnNumber argument was 0, and the TargetType argument was not SQL_C_BOOKMARK or SQL_C_VARBOOKMARK.
07009	Invalid descriptor index	The value specified for the argument ColumnNumber exceeded the maximum number of columns in the result set.
HY000	General error	An error occurred for which there was no specific SQLSTATE and for which no implementation-specific SQLSTATE was defined. The error message returned by SQLGetDiagRec in the *MessageText buffer describes the error and its cause.
HY001	Memory allocation error	The driver was unable to allocate memory that is required to support execution or completion of the function.
HY003	Invalid application buffer type	The argument TargetType was neither a valid data type nor SQL_C_DEFAULT.
HY010	Function sequence error	(DM) An asynchronously executing function was called for the connection handle that is associated with the StatementHandle. This asynchronous function was still executing when SQLBindCol was called. (DM) SQLExecute, SQLExecDirect, or SQLMoreResults was called for the StatementHandle and returned SQL_PARAM_DATA_AVAILABLE. This function was called before data was retrieved for all streamed parameters. (DM) An asynchronously executing function was called for the StatementHandle and was still executing when this function was called. (DM) SQLExecute, SQLExecDirect, SQLBulkOperations, or SQLSetPos was called for the StatementHandle and returned SQL_NEED_DATA. This function was called before data was sent for all data-at-execution parameters or columns.
HY013	Memory management error	The function call could not be processed because the underlying memory objects could not be accessed, possibly because of low memory conditions.
HY090	Invalid string or buffer length	(DM) The value specified for the argument BufferLength was less than 0. (DM) The driver was an ODBC 2.x driver, the ColumnNumber argument was set to 0, and the value specified for the argument BufferLength was not equal to 4.
HY117	Connection is suspended due to unknown transaction state. Only disconnect and read-only functions are allowed.	(DM) For more information about suspended state, see SQLEndTran Function.
HYC00	Optional feature not implemented	The driver or data source does not support the conversion specified by the combination of the TargetType argument and the driver-specific SQL data type of the corresponding column. The argument ColumnNumber was 0 and the driver does not support bookmarks. The driver supports only ODBC 2.x and the argument TargetType was one of the following: SQL_C_NUMERIC SQL_C_SBIGINT SQL_C_UBIGINT and any of the interval C data types listed in C Data Types in Appendix D: Data Types. The driver only supports ODBC versions prior to 3.50, and the argument TargetType was SQL_C_GUID.
HYT01	Connection timeout expired	The connection timeout period expired before the data source responded to the request. The connection timeout period is set through SQLSetConnectAttr, SQL_ATTR_CONNECTION_TIMEOUT.
IM001	Driver does not support this function	(DM) The driver associated with the StatementHandle does not support the function.

Comments

SQLBindCol is used to associate, or bind, columns in the result set to data buffers and length/indicator buffers in the application. When the application calls SQLFetch, SQLFetchScroll, or SQLSetPos to fetch data, the driver returns the data for the bound columns in the specified buffers; for more information, see SQLFetch Function. When the application calls SQLBulkOperations to update or insert a row or SQLSetPos to update a row, the driver retrieves the data for the bound columns from the specified buffers; for more information, see SQLBulkOperations Function or SQLSetPos Function. For more information about binding, see Retrieving Results (Basic).

Notice that columns do not have to be bound to retrieve data from them. An application can also call SQLGetData to retrieve data from columns. Although it is possible to bind some columns in a row and call SQLGetData for others, this is subject to some restrictions. For more information, see SQLGetData.

Binding, Unbinding, and Rebinding Columns

A column can be bound, unbound, or rebound at any time, even after data has been fetched from the result set. The new binding takes effect the next time that a function that uses bindings is called. For example, suppose an application binds the columns in a result set and calls SQLFetch. The driver returns the data in the bound buffers. Now suppose the application binds the columns to a different set of buffers. The driver does not put the data for the just-fetched row in the newly bound buffers. Instead, it waits until SQLFetch is called again and then places the data for the next row in the newly bound buffers.

Note

The statement attribute SQL_ATTR_USE_BOOKMARKS should always be set before binding a column to column 0. This is not required but is strongly recommended.

Binding Columns

To bind a column, an application calls SQLBindCol and passes the column number, type, address, and length of a data buffer, and the address of a length/indicator buffer. For information about how these addresses are used, see "Buffer Addresses," later in this section. For more information about binding columns, see Using SQLBindCol.

The use of these buffers is deferred; that is, the application binds them in SQLBindCol but the driver accesses them from other functions - namely SQLBulkOperations, SQLFetch, SQLFetchScroll, or SQLSetPos. It is the application's responsibility to make sure that the pointers specified in SQLBindCol remain valid as long as the binding remains in effect. If the application allows these pointers to become invalid - for example, it frees a buffer - and then calls a function that expects them to be valid, the consequences are undefined. For more information, see Deferred Buffers.

The binding remains in effect until it is replaced by a new binding, the column is unbound, or the statement is freed.

Unbinding Columns

To unbind a single column, an application calls SQLBindCol with ColumnNumber set to the number of that column and TargetValuePtr set to a null pointer. If ColumnNumber refers to an unbound column, SQLBindCol still returns SQL_SUCCESS.

To unbind all columns, an application calls SQLFreeStmt with fOption set to SQL_UNBIND. This can also be accomplished by setting the SQL_DESC_COUNT field of the ARD to zero.

Rebinding Columns

An application can perform either of two operations to change a binding:

Call SQLBindCol to specify a new binding for a column that is already bound. The driver overwrites the old binding with the new one.
Specify an offset to be added to the buffer address that was specified by the binding call to SQLBindCol. For more information, see the next section, "Binding Offsets."

Binding Offsets

A binding offset is a value that is added to the addresses of the data and length/indicator buffers (as specified in the TargetValuePtr and StrLen_or_IndPtr argument) before they are dereferenced. When offsets are used, the bindings are a "template" of how the application's buffers are laid out, and the application can move this "template" to different areas of memory by changing the offset. Because the same offset is added to each address in each binding, the relative offsets between buffers for different columns must be the same within each set of buffers. This is always true when row-wise binding is used; the application must carefully lay out its buffers for this to be true when column-wise binding is used.

Using a binding offset has basically the same effect as rebinding a column by calling SQLBindCol. The difference is that a new call to SQLBindCol specifies new addresses for the data buffer and length/indicator buffer, whereas use of a binding offset does not change the addresses but just adds an offset to them. The application can specify a new offset whenever it wants, and this offset is always added to the originally bound addresses. In particular, if the offset is set to 0 or if the statement attribute is set to a null pointer, the driver uses the originally bound addresses.

To specify a binding offset, the application sets the SQL_ATTR_ROW_BIND_OFFSET_PTR statement attribute to the address of an SQLINTEGER buffer. Before the application calls a function that uses bindings, it puts an offset in bytes in this buffer. To determine the address of the buffer to use, the driver adds the offset to the address in the binding. The sum of the address and the offset must be a valid address, but the address to which the offset is added does not have to be valid. For more information about how binding offsets are used, see "Buffer Addresses," later in this section.

Binding Arrays

If the rowset size (the value of the SQL_ATTR_ROW_ARRAY_SIZE statement attribute) is greater than 1, the application binds arrays of buffers instead of single buffers. For more information, see Block Cursors.

The application can bind arrays in two ways:

Bind an array to each column. This is referred to as column-wise binding because each data structure (array) contains data for a single column.
Define a structure to hold the data for a whole row and bind an array of these structures. This is referred to as row-wise binding because each data structure contains the data for a single row.

Each array of buffers must have at least as many elements as the size of the rowset.

Note

An application must verify that alignment is valid. For more information about alignment considerations, see Alignment.

Column-Wise Binding

In column-wise binding, the application binds separate data and length/indicator arrays to each column.

To use column-wise binding, the application first sets the SQL_ATTR_ROW_BIND_TYPE statement attribute to SQL_BIND_BY_COLUMN. (This is the default.) For each column to be bound, the application performs the following steps:

Allocates a data buffer array.
Allocates an array of length/indicator buffers.

Note

If the application writes directly to descriptors when column-wise binding is used, separate arrays can be used for length and indicator data.
Calls SQLBindCol with the following arguments:
- TargetType is the type of a single element in the data buffer array.
- TargetValuePtr is the address of the data buffer array.
- BufferLength is the size of a single element in the data buffer array. The BufferLength argument is ignored when the data is fixed-length data.
- StrLen_or_IndPtr is the address of the length/indicator array.

For more information about how this information is used, see "Buffer Addresses," later in this section. For more information about column-wise binding, see Column-Wise Binding.

Row-Wise Binding

In row-wise binding, the application defines a structure that contains data and length/indicator buffers for each column to be bound.

To use row-wise binding, the application performs the following steps:

Defines a structure to hold a single row of data (including both data and length/indicator buffers) and allocates an array of these structures.

Note

If the application writes directly to descriptors when row-wise binding is used, separate fields can be used for length and indicator data.
Sets the SQL_ATTR_ROW_BIND_TYPE statement attribute to the size of the structure that contains a single row of data or to the size of an instance of a buffer into which the results columns will be bound. The length must include space for all the bound columns, and any padding of the structure or buffer, to make sure that when the address of a bound column is incremented with the specified length, the result will point to the beginning of the same column in the next row. When using the sizeof operator in ANSI C, this behavior is guaranteed.
Calls SQLBindCol with the following arguments for each column to be bound:
- TargetType is the type of the data buffer member to be bound to the column.
- TargetValuePtr is the address of the data buffer member in the first array element.
- BufferLength is the size of the data buffer member.
- StrLen_or_IndPtr is the address of the length/indicator member to be bound.

For more information about how this information is used, see "Buffer Addresses," later in this section. For more information about column-wise binding, see Row-Wise Binding.

Buffer Addresses

The buffer address is the actual address of the data or length/indicator buffer. The driver calculates the buffer address just before it writes to the buffers (such as during fetch time). It is calculated from the following formula, which uses the addresses specified in the TargetValuePtr and StrLen_or_IndPtr arguments, the binding offset, and the row number:

Bound Address + Binding Offset + ((Row Number - 1) x Element Size)

where the formula's variables are defined as described in the following table.

Variable	Description
Bound Address	For data buffers, the address specified with the TargetValuePtr argument in SQLBindCol. For length/indicator buffers, the address specified with the StrLen_or_IndPtr argument in SQLBindCol. For more information, see "Additional Comments" in the "Descriptors and SQLBindCol" section. If the bound address is 0, no data value is returned, even if the address as calculated by the previous formula is nonzero.
Binding Offset	If row-wise binding is used, the value stored at the address specified with the SQL_ATTR_ROW_BIND_OFFSET_PTR statement attribute. If column-wise binding is used or if the value of the SQL_ATTR_ROW_BIND_OFFSET_PTR statement attribute is a null pointer, Binding Offset is 0.
Row Number	The 1-based number of the row in the rowset. For single-row fetches, which are the default, this is 1.
Element Size	The size of an element in the bound array. If column-wise binding is used, this is sizeof(SQLINTEGER) for length/indicator buffers. For data buffers, it is the value of the BufferLength argument in SQLBindCol if the data type is variable length, and the size of the data type if the data type is fixed length. If row-wise binding is used, this is the value of the SQL_ATTR_ROW_BIND_TYPE statement attribute for both data and length/indicator buffers.

Descriptors and SQLBindCol

The following sections describe how SQLBindCol interacts with descriptors.

Caution

Calling SQLBindCol for one statement can affect other statements. This occurs when the ARD associated with the statement is explicitly allocated and is also associated with other statements. Because SQLBindCol modifies the descriptor, the modifications apply to all statements with which this descriptor is associated. If this is not the required behavior, the application should dissociate this descriptor from the other statements before it calls SQLBindCol.

Argument Mappings

Conceptually, SQLBindCol performs the following steps in sequence:

Calls SQLGetStmtAttr to obtain the ARD handle.
Calls SQLGetDescField to get this descriptor's SQL_DESC_COUNT field, and if the value in the ColumnNumber argument exceeds the value of SQL_DESC_COUNT, calls SQLSetDescField to increase the value of SQL_DESC_COUNT to ColumnNumber.
Calls SQLSetDescField multiple times to assign values to the following fields of the ARD:
- Sets SQL_DESC_TYPE and SQL_DESC_CONCISE_TYPE to the value of TargetType, except that if TargetType is one of the concise identifiers of a datetime or interval subtype, it sets SQL_DESC_TYPE to SQL_DATETIME or SQL_INTERVAL, respectively; sets SQL_DESC_CONCISE_TYPE to the concise identifier; and sets SQL_DESC_DATETIME_INTERVAL_CODE to the corresponding datetime or interval subcode.
- Sets one or more of SQL_DESC_LENGTH, SQL_DESC_PRECISION, SQL_DESC_SCALE, and SQL_DESC_DATETIME_INTERVAL_PRECISION, as appropriate for TargetType.
- Sets the SQL_DESC_OCTET_LENGTH field to the value of BufferLength.
- Sets the SQL_DESC_DATA_PTR field to the value of TargetValuePtr.
- Sets the SQL_DESC_INDICATOR_PTR field to the value of StrLen_or_IndPtr. (See the following paragraph.)
- Sets the SQL_DESC_OCTET_LENGTH_PTR field to the value of StrLen_or_IndPtr. (See the following paragraph.)

The variable that the StrLen_or_IndPtr argument refers to is used for both indicator and length information. If a fetch encounters a null value for the column, it stores SQL_NULL_DATA in this variable; otherwise, it stores the data length in this variable. Passing a null pointer as StrLen_or_IndPtr keeps the fetch operation from returning the data length but makes the fetch fail if it encounters a null value and has no way to return SQL_NULL_DATA.

If the call to SQLBindCol fails, the content of the descriptor fields that it would have set in the ARD are undefined and the value of the SQL_DESC_COUNT field of the ARD is unchanged.

Implicit Resetting of COUNT Field

SQLBindCol sets SQL_DESC_COUNT to the value of the ColumnNumber argument only when this would increase the value of SQL_DESC_COUNT. If the value in the TargetValuePtr argument is a null pointer and the value in the ColumnNumber argument is equal to SQL_DESC_COUNT (that is, when unbinding the highest bound column), then SQL_DESC_COUNT is set to the number of the highest remaining bound column.

Cautions Regarding SQL_DEFAULT

To retrieve column data successfully, the application must determine correctly the length and starting point of the data in the application buffer. When the application specifies an explicit TargetType, application misconceptions are easily detected. However, when the application specifies a TargetType of SQL_DEFAULT, SQLBindCol can be applied to a column of a different data type from the one intended by the application, either from changes to the metadata or by applying the code to a different column. In this case, the application may not always determine the start or length of the fetched column data. This may lead to unreported data errors or memory violations.

Code Example

In the following example, an application executes a SELECT statement on the Customers table to return a result set of the customer IDs, names, and phone numbers, sorted by name. It then calls SQLBindCol to bind the columns of data to local buffers. Finally, the application fetches each row of data with SQLFetch and prints each customer's name, ID, and phone number.

For more code examples, see SQLBulkOperations Function, SQLColumns Function, SQLFetchScroll Function, and SQLSetPos Function.

// SQLBindCol_ref.cpp  
// compile with: odbc32.lib  
#include <windows.h>  
#include <stdio.h>  
  
#define UNICODE  
#include <sqlext.h>  
  
#define NAME_LEN 50  
#define PHONE_LEN 60
  
void show_error() {  
   printf("error\n");  
}  
  
int main() {  
   SQLHENV henv;  
   SQLHDBC hdbc;  
   SQLHSTMT hstmt = 0;  
   SQLRETURN retcode;  
   SQLWCHAR szName[NAME_LEN], szPhone[PHONE_LEN], sCustID[NAME_LEN];  
   SQLLEN cbName = 0, cbCustID = 0, cbPhone = 0;  
  
   // Allocate environment handle  
   retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &henv);  
  
   // Set the ODBC version environment attribute  
   if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {  
      retcode = SQLSetEnvAttr(henv, SQL_ATTR_ODBC_VERSION, (SQLPOINTER*)SQL_OV_ODBC3, 0);   
  
      // Allocate connection handle  
      if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {  
         retcode = SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc);  
  
         // Set login timeout to 5 seconds  
         if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {  
            SQLSetConnectAttr(hdbc, SQL_LOGIN_TIMEOUT, (SQLPOINTER)5, 0);  
  
            // Connect to data source  
            retcode = SQLConnect(hdbc, (SQLWCHAR*) L"NorthWind", SQL_NTS, (SQLWCHAR*) NULL, 0, NULL, 0);  
  
            // Allocate statement handle  
            if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {   
               retcode = SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt);   
  
               retcode = SQLExecDirect(hstmt, (SQLWCHAR *) L"SELECT CustomerID, ContactName, Phone FROM CUSTOMERS ORDER BY 2, 1, 3", SQL_NTS);  
               if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {  
  
                  // Bind columns 1, 2, and 3  
                  retcode = SQLBindCol(hstmt, 1, SQL_C_WCHAR, &sCustID, 100, &cbCustID);  
                  retcode = SQLBindCol(hstmt, 2, SQL_C_WCHAR, szName, NAME_LEN, &cbName);  
                  retcode = SQLBindCol(hstmt, 3, SQL_C_WCHAR, szPhone, PHONE_LEN, &cbPhone);   
  
                  // Fetch and print each row of data. On an error, display a message and exit.  
                  for (int i=0 ; ; i++) {  
                     retcode = SQLFetch(hstmt);  
                     if (retcode == SQL_ERROR || retcode == SQL_SUCCESS_WITH_INFO)  
                        show_error();  
                     if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)  
                     {
                        //replace wprintf with printf
                        //%S with %ls
                        //warning C4477: 'wprintf' : format string '%S' requires an argument of type 'char *'
                        //but variadic argument 2 has type 'SQLWCHAR *'
                        //wprintf(L"%d: %S %S %S\n", i + 1, sCustID, szName, szPhone);  
                        printf("%d: %ls %ls %ls\n", i + 1, sCustID, szName, szPhone);  
                    }    
                     else  
                        break;  
                  }  
               }  
  
               // Process data  
               if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO) {  
                  SQLCancel(hstmt);  
                  SQLFreeHandle(SQL_HANDLE_STMT, hstmt);  
               }  
  
               SQLDisconnect(hdbc);  
            }  
  
            SQLFreeHandle(SQL_HANDLE_DBC, hdbc);  
         }  
      }  
      SQLFreeHandle(SQL_HANDLE_ENV, henv);  
   }  
}

Also see, Sample ODBC Program.

For information about	See
Returning information about a column in a result set	SQLDescribeCol Function
Fetching a block of data or scrolling through a result set	SQLFetchScroll Function
Fetching multiple rows of data	SQLFetch Function
Releasing column buffers on the statement	SQLFreeStmt Function
Fetching part or all of a column of data	SQLGetData Function
Returning the number of result set columns	SQLNumResultCols Function

Sdílet prostřednictvím

SQLBindCol Function

Syntax

Arguments

Returns

Diagnostics

Comments

Binding, Unbinding, and Rebinding Columns

Binding Columns

Unbinding Columns

Rebinding Columns

Binding Offsets

Binding Arrays

Column-Wise Binding

Row-Wise Binding

Buffer Addresses

Descriptors and SQLBindCol

Argument Mappings

Implicit Resetting of COUNT Field

Cautions Regarding SQL_DEFAULT

Code Example

See Also

Váš názor

Další materiály

Sdílet prostřednictvím

SQLBindCol Function

Syntax

Arguments

Returns

Diagnostics

Comments

Binding, Unbinding, and Rebinding Columns

Binding Columns

Unbinding Columns

Rebinding Columns

Binding Offsets

Binding Arrays

Column-Wise Binding

Row-Wise Binding

Buffer Addresses

Descriptors and SQLBindCol

Argument Mappings

Implicit Resetting of COUNT Field

Cautions Regarding SQL_DEFAULT

Code Example

Related Functions

See Also

Váš názor

Další materiály