CODEWITHSUNDEEP
c#postgresql
Shakoor Alam
Shakoor Alam

Reputation: 197

How to get Bytea Data in string from Postgres Database

Is there a way to get the actual encoded string saved in the Database of column with DataType Bytea. Because when the record is fetched in C# it returns as System.Byte[] which I don't want. I want the data which is saved in that column

E'\\\142\\\247\\\ and so on till the data ends.

I will appreciate your support

When I am querying the data through 

SELECT tpl::TEXT from Cards where ecode="xyz";

I get the following error

Error: Cannot cast type bytea to text
Line1: Select tpl::TEXT from cards

Thank you

Like this

Normal query

enter image description here

As you see that the Bytea column is showing System.Byte[] which was overwritten by my application because the code in C# stores the data in the DataTable column as System.Byte[] while updating the data I didn't decode it and update it .

I am using Navicat premium when I query data it shows me the result when I right click on the grid result and copy as insert statement it shows me two result for different rows

like this

INSERT INTO "public"."cards" ("ecode", "tpl") VALUES ('4210149888659', E'System.Byte[]');

INSERT INTO "public"."cards" ("ecode", "tpl") VALUES('3650257637661',E '\\247\\377\\001\\021\\340\\000\\230\\000\\002U\\000e\\000\\362\\000\\002-\\000\\253\\000p\\000\\002\\207\\000~\\000g\\000\\002\\215\\000{\\000\\317\\000\\002\\334\\000h\\000\\222\\000\\001|\\000\\004\\001U\\000\\002\\202\\000K\\000\\201\\000\\001\\000\\000\\204\\000\\241\\000\\001w\\000\\213\\000\\305\\000\\002\\021\\000V\\000\\237\\000\\002L\\001=\\001\\364\\000\\001X\\001"\\001\\313\\000\\002J\\000\\010\\001\\324\\000\\001\\370\\000\\037\\001J\\000\\002;\\0017\\000\\202\\000\\002\\300\\000\\317\\0007\\000\\002\\215\\000[\\000\\004\\011\\017\\007\\012\\005\\015\\014\\006\\016\\012\\007\\010\\005\\005\\007\\011\\010\\001\\004\\012\\017\\002\\003\\010\\012\\004\\010\\005\\003\\013\\014\\005\\017\\007\\003\\010\\003\\001\\011\\004\\012\\006\\020\\011\\005\\013\\015\\010\\002\\004\\005\\010\\007\\011\\012\\000\\002\\002\\020\\012\\003\\015\\000\\005\\002\\017\\003\\000\\006\\016\\020\\010\\017\\014\\000\\001\\012\\001\\010\\011\\002\\004\\007\\010\\000\\002\\006\\011\\007\\003\\020\\011\\003\\001\\005\\011\\000\\007\\002\\012\\002\\000\\020\\000\\016\\004\\017\\004\\003\\011\\017\\000\\003\\004\\000\\001\\007\\017\\002\\001\\017\\014\\006\\002\\016\\015\\011\\015\\006\\014\\016\\010\\020\\013\\000\\003\\006\\015\\002\\005\\020\\015\\016\\015\\004\\001\\003\\015\\010\\010\\006\\014\\002\\007\\020\\014\\011\\001\\000\\014\\010\\003\\016\\001\\015\\017\\020\\013\\006\\013\\016\\013\\011\\001\\014\\013\\004\\013\\002\\013\\001\\000'
);

Upvotes: 1

Views: 5376

Answers (1)

Chris Travers
Chris Travers

Reputation: 26464

You can't just convert it because PostgreSQL can't guarantee it can be converted safely. The best you can do is to convert the escaped form into a string and that's not what you probably want. Keep in mind that since bytea is binary data there is no way that PostgreSQL can be sure that the string that comes out will be legit. You could have embedded nulls in a UTF-8 string, for example, which could cause some fun with buffer overruns if you aren't careful.

This is the sort of thing that should be done in the client-side and you should assume that the data is binary, and not necessarily a valid string. If you want to store strings, store text fields, not bytea.

Upvotes: 0

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