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OpenAccess SDK SQL Engine core methods for .NET : Methods for .NET reference : dam_getFirstCol
 

dam_getFirstCol

This method is used to navigate through the columns that appear in the SELECT and WHERE of the SQL query, or through the columns in the schema definition of the table. Call this method, with the column types to be navigated, and then use dam_getNextCol to step through the list.
The dam_getFirstCol method is used to:
• Write an IP that is dynamic in that it does not hard-code any column names
• To optimize an IP where it first builds a row with only the columns in the WHERE clause and then adds the columns in the SELECT part only if dam_isTargetRow returns TRUE.
int64 dam_getFirstCol(
int64 hstmt,
int iColType)
 
Table 135: Parameters for dam_getFirstCol 
Parameter
Type
Description
IN
 
 
hstmt
int64
The statement handle
iColType
int
Identifies the column list to navigate. Use a bitwise OR ( | ) of the following flags to scan through columns that are in multiple categories:
DAM_COL_IN_SCHEMA – list of all columns as defined in the schema database
DAM_COL_IN_RESULT – list of columns that are part of the result set
DAM_COL_IN_CONDITION – list of columns that are in the WHERE clause
DAM_COL_IN_UPDATE_VAL_EXP – list of all columns that are part of update value expressions.
DAM_COL_IN_USE – list of columns that are either part of the result or are in the WHERE clause. The row passed to dam_addRowToTable must include at minimum all the columns in this list.
RETURN
 
 
 
int64
The handle to the first column that has the attributes of iColType; otherwise, 0.

See also

• dam_getNextCol
• dam_isTargetRow