A pretty good read / intro to the concept of keys in the relational model: https://www.red-gate.com/simple-talk/sql/learn-sql-server/primary-key-primer-for-sql-server/
- Jon <https://www.linkedin.com/in/jonstrong/> <https://www.jonathanrstrong.com> *Jonathan Strong* CIO / CTO / Consultant *P:* 609-532-1715 *E:* jonathanrstr...@gmail.com *Quora Top Writer <https://www.quora.com/profile/Jonathan-R-Strong>* On Fri, Sep 18, 2020 at 3:08 PM Adrian Klaver <adrian.kla...@aklaver.com> wrote: > On 9/18/20 11:49 AM, Igor Korot wrote: > > Hi, Adrian, > > > > On Fri, Sep 18, 2020 at 12:58 PM Adrian Klaver > > <adrian.kla...@aklaver.com> wrote: > >> > >> On 9/18/20 10:46 AM, Igor Korot wrote: > >>> Hi, Johnathan, > >>> > >>> On Fri, Sep 18, 2020 at 12:34 PM Jonathan Strong > >>> <jonathanrstr...@gmail.com <mailto:jonathanrstr...@gmail.com>> wrote: > >>> > >>> Are you looking to arbitrarily update the field in the fifth row, > or > >>> can the row that needs to be updated be isolated by some add'l > >>> attribute? What's the use case? > >>> > >>> > >>> What do you mean? > >>> I don't have any other attributes. > >>> > >>> I want to understand how to emulate MS Access behavior, where you have > a > >>> form > >>> with the arbitrary query, then you can go to any record in that form > and > >>> update any field. > >>> > >>> Is it even possible from the "pure SQL" POV? Or Access is doing some > >>> VBA/DB/4GL magic? > >>> > >> > >> When you are updating a record in a form the framework(Access in your > >> case) is using some identifier from that record to UPDATE that > >> particular record in the database. From when I used Access, I seem to > >> remember it would not give you INSERT/UPDATE capability on a form unless > >> you had specified some unique key for the records. So you need to find > >> what the key(generally a PRIMARY KEY) is and use that to do the UPDATE. > > > > But now the question becomes > > > > How to find what the primary key (or UNIQUE identifier) value is > > for row 5 in the recordset? > > You defined them: > > CREATE TABLE X(id INTEGER PRIMARY KEY, field1 char(50), field2 int); > CREATE TABLE Y(id INTEGER PRIMARY KEY, field1 char, field2 double(10, 2)); > > How you fetch that value is going to depend on where the record set is > being presented and how the record to be UPDATEd is selected? If you are > using some sort of framework/form to display the records it will have > some mechanism to gather the information(data) on select and then you > can use the PRIMARY KEY value from that data to do the UPDATE. If you > want a more precise answer then you will need to provide a complete > example of what you are doing. > > > > > Thank you. > > > >> > >>> Thank you. > >>> > >> > >> > >> > >> -- > >> Adrian Klaver > >> adrian.kla...@aklaver.com > > > -- > Adrian Klaver > adrian.kla...@aklaver.com >
