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2015年12月21日
#
ld在链接的时候找不到所需的动态库 1、安装所需的动态库 2、修改链接查找路径配置文件 二选一 a）、在有root权限情况下： echo "usr/local/lib >> /etc/ld.so.conf" b)、在没有root权限的情况下： $ echo "export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH" >> ~/.bashrc
ps:查找库的方法
$ locate libiconv.so.2
$ whereis libiconv.so.2
$ find /usr /lib -name libiconv.so.2
$ find / -name libiconv.so.2 2>/dev/null
2015年12月20日
#
cat -A 能看到符号 Windows: ^M$ CR LF Linux: $ LF 对于文本问题，可以使用 UNIX2dox、dos2UNIX 转换
2011年4月6日
#
 // 把一个wstring转化为string
std::string& to_string(std::string& dest, std::wstring const & src)
   {
 std::setlocale(LC_CTYPE, "");
size_t const mbs_len = wcstombs(NULL, src.c_str(), 0);
std::vector<char> tmp(mbs_len + 1);
wcstombs(&tmp[0], src.c_str(), tmp.size());
dest.assign(tmp.begin(), tmp.end() - 1);
return dest;
 }
// 把一个string转化为wstring
std::wstring& to_wstring(std::wstring& dest, std::string const & src)
{
std::setlocale(LC_CTYPE, "");
size_t const wcs_len = mbstowcs(NULL, src.c_str(), 0);
std::vector<wchar_t> tmp(wcs_len + 1);
mbstowcs(&tmp[0], src.c_str(), src.size());
dest.assign(tmp.begin(), tmp.end() - 1);
return dest;
2008年9月12日
#
老板要求重用SQLHSTMT句柄，找到一些资料
1、使用SQLExecDirect执行了查询语句，记录集会存放在hstmt中，
2、通过SQLBindCol把记录集和变量绑定。
3、SQLFreeStmt(hstmt, SQL_UNBIND);释放由先前对此语句句柄进行的
SQLBindCol() 调用绑定的所有列（应用程序变量或文件引用与结果集列之间的关联将断开）。
4、SQLCloseCursor(hstmt);将关闭任何与语句句柄相关联的游标并废弃任何暂挂结果
如果不需要使用返回的结果集
1、使用SQLExecDirect执行了查询语句，记录集会存放在hstmt中，
2、SQLCloseCursor(hstmt)或者SQLFreeStmt(hstmt,SQL_CLOSE )将关闭任何与语句句柄相关联的游标并废弃任何暂挂结果
2008年9月11日
#
SQLExecDirect函数源代码
static SQLRETURN
ODBCExecDirect(ODBCStmt *stmt, SQLCHAR *szSqlStr, SQLINTEGER nSqlStr)
{
char *query;
MapiMsg ret;
MapiHdl hdl;
hdl = stmt->hdl;
if (stmt->State >= EXECUTED1 || (stmt->State == EXECUTED0 && mapi_more_results(hdl))) {
/* Invalid cursor state */
addStmtError(stmt, "24000", NULL, 0);
return SQL_ERROR;
}
/* TODO: convert ODBC escape sequences ( {d 'value'} or {t 'value'} or
{ts 'value'} or {escape 'e-char'} or {oj outer-join} or
{fn scalar-function} etc. ) to MonetDB SQL syntax */
query = ODBCTranslateSQL(szSqlStr, (size_t) nSqlStr, stmt->noScan);
ODBCResetStmt(stmt);
#ifdef ODBCDEBUG
ODBCLOG("SQLExecDirect: \"%s\"\n", query);
#endif
ret = mapi_query_handle(hdl, query);
free(query);
switch (ret) {
case MOK:
break;
case MTIMEOUT:
/* Communication link failure */
addStmtError(stmt, "08S01", mapi_error_str(stmt->Dbc->mid), 0);
return SQL_ERROR;
default:
/* General error */
addStmtError(stmt, "HY000", mapi_error_str(stmt->Dbc->mid), 0);
return SQL_ERROR;
}
/* now get the result data and store it to our internal data structure */
return ODBCInitResult(stmt);
}
As mentioned earlier, it is more efficient to reuse statements than to drop them and allocate new ones. Before executing a new SQL statement on a statement, applications should be sure that the current statement settings are appropriate. These include statement attributes, parameter bindings, and result set bindings. Generally, parameters and result sets for the old SQL statement need to be unbound (by calling SQLFreeStmt with the SQL_RESET_PARAMS and SQL_UNBIND options) and rebound for the new SQL statement.
When the application has finished using the statement, it calls SQLFreeHandle to free the statement. After freeing the statement, it is an application programming error to use the statement's handle in a call to an ODBC function; doing so has undefined but probably fatal consequences.
When SQLFreeHandle is called, the driver releases the structure used to store information about the statement.
SQLDisconnect automatically frees all statements on a connection.
/**********************************************
* ODBCStmt.c
*
* Description:
* This file contains the functions which operate on
* ODBC statement structures/objects (see ODBCStmt.h).
*
* Author: Martin van Dinther
* Date : 30 aug 2002
*
**********************************************/
#include "ODBCGlobal.h"
#include "ODBCStmt.h"
#define ODBC_STMT_MAGIC_NR 5461 /* for internal sanity check only */
/*
* Creates a new allocated ODBCStmt object and initializes it.
*
* Precondition: none
* Postcondition: returns a new ODBCStmt object
*/
ODBCStmt *
newODBCStmt(ODBCDbc *dbc)
{
ODBCStmt *stmt = (ODBCStmt *) malloc(sizeof(ODBCStmt));
assert(stmt);
assert(dbc);
assert(dbc->mid);
if (stmt == NULL) {
/* Memory allocation error */
addDbcError(dbc, "HY001", NULL, 0);
return NULL;
}
stmt->Dbc = dbc;
stmt->Error = NULL;
stmt->RetrievedErrors = 0;
stmt->State = INITED;
stmt->hdl = mapi_new_handle(dbc->mid);
if (stmt->hdl == NULL) {
/* Memory allocation error */
addDbcError(dbc, "HY001", NULL, 0);
free(stmt);
return NULL;
}
assert(stmt->hdl);
stmt->currentRow = 0;
stmt->startRow = 0;
stmt->rowSetSize = 0;
stmt->queryid = -1;
stmt->nparams = 0;
stmt->querytype = -1;
stmt->rowcount = 0;
/* add this stmt to the administrative linked stmt list */
stmt->next = dbc->FirstStmt;
dbc->FirstStmt = stmt;
stmt->cursorType = SQL_CURSOR_FORWARD_ONLY;
stmt->cursorScrollable = SQL_NONSCROLLABLE;
stmt->retrieveData = SQL_RD_ON;
stmt->noScan = SQL_NOSCAN_OFF;
stmt->ApplRowDescr = newODBCDesc(dbc);
stmt->ApplParamDescr = newODBCDesc(dbc);
stmt->ImplRowDescr = newODBCDesc(dbc);
stmt->ImplParamDescr = newODBCDesc(dbc);
stmt->AutoApplRowDescr = stmt->ApplRowDescr;
stmt->AutoApplParamDescr = stmt->ApplParamDescr;
if (stmt->ApplRowDescr == NULL || stmt->ApplParamDescr == NULL || stmt->ImplRowDescr == NULL || stmt->ImplParamDescr == NULL) {
destroyODBCStmt(stmt);
return NULL;
}
stmt->ApplRowDescr->sql_desc_alloc_type = SQL_DESC_ALLOC_AUTO;
stmt->ApplParamDescr->sql_desc_alloc_type = SQL_DESC_ALLOC_AUTO;
stmt->ImplRowDescr->sql_desc_alloc_type = SQL_DESC_ALLOC_AUTO;
stmt->ImplParamDescr->sql_desc_alloc_type = SQL_DESC_ALLOC_AUTO;
stmt->ImplRowDescr->Stmt = stmt;
stmt->ImplParamDescr->Stmt = stmt;
stmt->Type = ODBC_STMT_MAGIC_NR; /* set it valid */
return stmt;
}
SQLFreeHandle
ODBCFreeStmt_(ODBCStmt *stmt)
{
/* check if statement is not active */
if (stmt->State >= EXECUTED0) {
/* should be closed first */
if (SQLFreeStmt_(stmt, SQL_CLOSE) == SQL_ERROR)
return SQL_ERROR;
}
/* Ready to destroy the stmt handle */
destroyODBCStmt(stmt);
return SQL_SUCCESS;
}
SQLFreeStmt
SQLFreeStmt_(ODBCStmt *stmt, SQLUSMALLINT option)
{
switch (option) {
case SQL_CLOSE:
/* Note: this option is also called from SQLCancel() and
SQLCloseCursor(), so be careful when changing the code */
/* close cursor, discard result set, set to prepared */
setODBCDescRecCount(stmt->ImplRowDescr, 0);
stmt->currentRow = 0;
stmt->startRow = 0;
stmt->rowSetSize = 0;
if (stmt->State == EXECUTED0)
stmt->State = stmt->queryid >= 0 ? PREPARED0 : INITED;
else if (stmt->State >= EXECUTED1)
stmt->State = stmt->queryid >= 0 ? PREPARED1 : INITED;
/* Important: do not destroy the bind parameters and columns! */
return SQL_SUCCESS;
case SQL_DROP:
return ODBCFreeStmt_(stmt);
case SQL_UNBIND:
setODBCDescRecCount(stmt->ApplRowDescr, 0);
return SQL_SUCCESS;
case SQL_RESET_PARAMS:
setODBCDescRecCount(stmt->ApplParamDescr, 0);
setODBCDescRecCount(stmt->ImplParamDescr, 0);
mapi_clear_params(stmt->hdl);
return SQL_SUCCESS;
default:
/* Invalid attribute/option identifier */
addStmtError(stmt, "HY092", NULL, 0);
return SQL_ERROR;
}
/* not reached */
}
SQLHSTMT的结构
typedef struct tODBCDRIVERSTMT {
/* Stmt properties */
int Type; /* structure type, used for handle validy test */
ODBCError *Error; /* pointer to an Error object or NULL */
int RetrievedErrors; /* # of errors already retrieved by SQLError */
ODBCDbc *Dbc; /* Connection context */
struct tODBCDRIVERSTMT *next; /* the linked list of stmt's in this Dbc */
enum StatementState State; /* needed to detect invalid cursor state */
MapiHdl hdl;
unsigned int rowcount; /* # affected rows */
/* startRow is the row number of first row in the result
set (0 based); rowSetSize is the number of rows in the
current result set; currentRow is the row number of the
current row within the current result set */
unsigned int currentRow;
unsigned int startRow;
unsigned int rowSetSize;
unsigned int currentCol; /* used by SQLGetData() */
SQLINTEGER retrieved; /* amount of data retrieved */
int queryid; /* the query to be executed */
int nparams; /* the number of parameters expected */
int querytype; /* query type as returned by server */
SQLUINTEGER cursorType;
SQLUINTEGER cursorScrollable;
SQLUINTEGER retrieveData;
SQLUINTEGER noScan;
ODBCDesc *ApplRowDescr; /* Application Row Descriptor (ARD) */
ODBCDesc *ApplParamDescr; /* Application Parameter Descriptor (APD) */
ODBCDesc *ImplRowDescr; /* Implementation Row Descriptor (IRD) */
ODBCDesc *ImplParamDescr; /* Implementation Parameter Descriptor (IPD) */
ODBCDesc *AutoApplRowDescr; /* Auto-allocated ARD */
ODBCDesc *AutoApplParamDescr; /* Auto-allocated APD */
/* Stmt children: none yet */
} ODBCStmt;
2008年2月26日
#
2008年1月31日
#
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