Security can take one of two values: SECURITY DEFINER and SECURITY INVOKER and is responsible for which user it will be called with. It will also be specified by default if none of the above arguments is specified when creating the function. It remains VOLATILE, which lacks the above problems. The function with the STABLE parameter is not suitable for AFTER triggers that want to read lines modified by the current command. VOLATILE means that the result of a function can change even within a single table scan, so its calls cannot be optimized.Īccordingly, if the trigger function requires changing the database, then IMMUTABLE is not appropriate.STABLE means that the function cannot modify the database, and within the same table scan it always returns the same result for certain values of the arguments.IMMUTABLE means that the function cannot modify the database and always returns the same result with certain values of the arguments.From the official PostgreSQL documentation, you can find out that these arguments inform the query optimizer about the behavior of the function. įunction Type can take one of three values: IMMUTABLE, STABLE and VOLATILE. With the remaining parameters, everything is not so obvious, at least for me, because I never had to think about them in the normal creation of a function in PostgreSQL. But since we just need one value, not an array, we leave 0 in this field. Dimension field (the only unsigned numeric field in this block) is needed to indicate the dimension of the return value array. Because the function will be called in a trigger, then in the Type field we specify the trigger (the Format field will be automatically filled with the value of the trigger ). With the parameters in the Data Type block, in general, everything is also simple. Since in the trigger function neither the table ( Table ) nor the set ( Set ) of values is needed, we leave Simple. Therefore, it is precisely this value that was chosen for the parameter. To be honest, I have never had to write functions for PostgreSQL on anything other than plpgsql. Language is the name of the language in which the function will be implemented. I think with the parameters Name, Schema, Owner and Comment everything is clear - this is the name of the function, the database schema, the owner and the comment to this function, respectively. In this case, some fields will already be filled with default values. Īs an example, consider a simplified model with a single table.Īfter that, a window will open with various editable parameters with which the function will be created. Details about this tool and its capabilities can be found on the official site. PgModeler is a very good database design tool that can generate sql scripts for PostgreSQL. It is also easy, but I had to sort out a bit with the parameters offered for filling / selection in the interface. it took me to add a trigger to the model on pgModeler. In a certain kingdom, in a certain state.
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