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For example, if I want to call the createPartitionedTable (createPartitionedTable — DolphinDB 2.0 documentation ), what script should I write?

yiniwei
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1 Answers1

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The built-in functions are classified into operator functions and system functions, which are called with different prototypes.

  • Operator functions: call(Heap, const ConstantSP&, const ConstantSP&).

  • System functions: call(Heap, vector&).

There are two functions that can identify whether a function is a system function or the other kind.

inline bool isSystemFunction() const {return defType_ == SYSFUNC;}
inline FUNCTIONDEF_TYPE getFunctionDefType() const {return defType_;}

For how these two different functions can be called, you can refer to the following scripts:

createPartitionedTable is called as a system function:

vector<ConstantSP> args{dbHandle, load(MySQLTableName_or_query, schema, 0, 1), new String(tableName), partitionColumns};
ret = heap->currentSession()->getFunctionDef("createPartitionedTable")->call(heap, args);

cumsum is called as an operator function:

ConstantSP v = Util::createIndexVector(1, 100);
v->setTemporary(false);                                   //The value of v may be modified when calling a built-in function. If you do not expect that, call setTemporary(false) firstly.
FunctionDefSP cumsum = heap->currentSession()->getFunctionDef("cumsum");
ConstantSP result = cumsum->call(heap, v, new Void());
// That is equivalent to cumsum(v), where new Void() is a placeholder with no practical use.
lulunolemon
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  • As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Mar 28 '23 at 08:42