How to check whether a data type can be cast to another
| От | Kareem Sedki |
|---|---|
| Тема | How to check whether a data type can be cast to another |
| Дата | |
| Msg-id | 4AE16B83.1020501@gmail.com обсуждение исходный текст |
| Ответы |
Re: How to check whether a data type can be cast to another
Re: How to check whether a data type can be cast to another |
| Список | pgsql-general |
Hello all,
I am trying to write a function that takes one source and one target data type identifiers, each as a 'text' variable, as arguments and return true if the cast can be made, false otherwise.
I consulted the pg_cast and pg_type tables, however, I found no direct casts from 'int4' to 'text'. Even though, you SELECT CAST(4::int4 AS text) The possibility of indirect casts that use multiple intermediate casts is slim - to me. Is an 'int4' cast to 'text' by means of multiple intermediate casts from 'int4' to 'char' and eventually to 'text'?
I would prefer to have a function written in PG/PLSQL for now as we are prototyping the system. Could someone help me write such a function, please?
Thank you in advance.
I am trying to write a function that takes one source and one target data type identifiers, each as a 'text' variable, as arguments and return true if the cast can be made, false otherwise.
I consulted the pg_cast and pg_type tables, however, I found no direct casts from 'int4' to 'text'. Even though, you SELECT CAST(4::int4 AS text) The possibility of indirect casts that use multiple intermediate casts is slim - to me. Is an 'int4' cast to 'text' by means of multiple intermediate casts from 'int4' to 'char' and eventually to 'text'?
I would prefer to have a function written in PG/PLSQL for now as we are prototyping the system. Could someone help me write such a function, please?
Thank you in advance.
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