本文整理汇总了C++中ExpGenerator::createExprTree方法的典型用法代码示例。如果您正苦于以下问题：C++ ExpGenerator::createExprTree方法的具体用法？C++ ExpGenerator::createExprTree怎么用？C++ ExpGenerator::createExprTree使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类ExpGenerator的用法示例。
在下文中一共展示了ExpGenerator::createExprTree方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: vc
ItemExpr * buildEncodeTree(desc_struct * column,
desc_struct * key,
NAString * dataBuffer, //IN:contains original value
Generator * generator,
ComDiagsArea * diagsArea)
{
ExpGenerator * expGen = generator->getExpGenerator();
// values are encoded by evaluating the expression:
// encode (cast (<dataBuffer> as <datatype>))
// where <dataBuffer> points to the string representation of the
// data value to be encoded, and <datatype> contains the
// PIC repsentation of the columns's datatype.
// create the CAST part of the expression using the parser.
// if this is a nullable column and the key value passed in
// is a NULL value, then treat it as a special case. A NULL value
// is passed in as an unquoted string of characters NULL in the
// dataBuffer. This case has to be treated different since the
// parser doesn't recognize the syntax "CAST (NULL as <datatype>)".
NAString ns;
ItemExpr * itemExpr;
NABoolean nullValue = FALSE;
NABoolean caseinsensitiveEncode = FALSE;
if (column->body.columns_desc.caseinsensitive)
caseinsensitiveEncode = TRUE;
if (column->body.columns_desc.null_flag &&
dataBuffer->length() >= 4 &&
str_cmp(*dataBuffer, "NULL", 4) == 0)
{
nullValue = TRUE;
ns = "CAST ( @A1 AS ";
ns += column->body.columns_desc.pictureText;
ns += ");";
// create a NULL constant
ConstValue * nullConst = new(expGen->wHeap()) ConstValue();
nullConst->synthTypeAndValueId();
itemExpr = expGen->createExprTree(ns,
CharInfo::UTF8,
ns.length(),
1, nullConst);
}
else
{
ns = "CAST ( ";
ns += *dataBuffer;
ns += " AS ";
ns += column->body.columns_desc.pictureText;
ns += ");";
itemExpr = expGen->createExprTree(ns,
CharInfo::UTF8,
ns.length());
}
CMPASSERT(itemExpr != NULL);
ItemExpr *boundItemExpr =
itemExpr->bindNode(generator->getBindWA());
if (boundItemExpr == NULL)
return NULL;
// make sure that the source and target values have compatible type.
// Do this only if source is not a null value.
NAString srcval;
srcval = "";
srcval += *dataBuffer;
srcval += ";";
ItemExpr * srcNode = expGen->createExprTree(srcval, CharInfo::UTF8, srcval.length());
CMPASSERT(srcNode != NULL);
srcNode->synthTypeAndValueId();
if ((NOT nullValue) &&
(NOT srcNode->getValueId().getType().isCompatible(itemExpr->getValueId().getType())))
{
if (diagsArea)
{
emitDyadicTypeSQLnameMsg(-4039,
itemExpr->getValueId().getType(),
srcNode->getValueId().getType(),
column->body.columns_desc.colname,
NULL,
diagsArea);
}
return NULL;
}
if (column->body.columns_desc.null_flag)
((NAType *)&(itemExpr->getValueId().getType()))->setNullable(TRUE);
else
((NAType *)&(itemExpr->getValueId().getType()))->setNullable(FALSE);
// Explode varchars by moving them to a fixed field
// whose length is equal to the max length of varchar.
////collation??
//.........这里部分代码省略.........