git - how to chain two migrations through migraions ids and to create a linear chain to collapse the branches? -

-

i deployed flask app heroku. when run command error.

heroku run python manage.py deploy

this error message:

raise util.commanderror('only single head supported. ' alembic.util.commanderror: single head supported. script directory has multiple heads (due branching), must resolved manually editing revision files form linear sequence. run alembic branches see divergence(s).

ao googled it,then got this:

this happens when go revision not last , create new migration. have 2 branches, alembic cannot handle.look @ how migration files chained through migration ids, need create linear chain collapse branches.

but i'm still confused how solve that. think problem caused git branches. (i tried merge 2 branches, didn't work?)

looks quoted comment made long ago in 1 of blog articles. since then, have written article dedicated topic of resolving migration conflicts: http://blog.miguelgrinberg.com/post/resolving-database-schema-conflicts

this explained in article, basically, have edit migration scripts form linear sequence. each script has pointer predecessor, conflict occurs when have 2 or more scripts have same predecessor. have migrations b , c, both predecessor. this:

     --> b __/     \      --> c

assuming @ migration b, c migration cannot applied because on different branch. 1 possible way address conflict change predecessor in c script b. migration chain becomes:

a --> b --> c

so alembic can move b c.

another option, supported in recent versions of alembic use merge command create merge migration. cover briefly in article well, isn't preferred solution.


Comments

Post a Comment

Popular posts from this blog

wordpress - (T_ENDFOREACH) php error -

-
creating wordpress website , i'm getting following php error: parse error: syntax error, unexpected 'endforeach' (t_endforeach) in /home/soralmedia/public_html/wp-content/themes/soral media/woocommerce/myaccount/my-orders.php on line 98 here's code file: <?php /** * orders * * shows recent orders on account page. * * template can overridden copying yourtheme/woocommerce/myaccount/my-orders.php. * * however, on occasion woocommerce need update template files , (the theme developer). * need copy new files theme maintain compatibility. try this. * little possible, happen. when occurs version of template file will. * bumped , readme list important changes. * * @see http://docs.woothemes.com/document/template-structure/ * @author woothemes * @package woocommerce/templates * @version 2.5.0 */ if ( ! defined( 'abspath' ) ) { exit; } $my_orders_columns = apply_filters( 'woocommerce_my_account_my_orders_columns', array( ...
Read more

Export Excel workseet into txt file using vba - (text and numbers with formulas) -

-
i new vba have developed code use in excel move text/numbers txt file. issue have 3 functions need go same txt file. when run first function has set fs = createobject("scripting.filesystemobject") set = fs.createtextfile(module1.nys45uploadfilename, true) a.writeline (str) a.close. the other 2 functions had save. set fs = createobject("scripting.filesystemobject") set = fs.savetextfile(module1.nys45uploadfilename, true) a.writeline (str) a.close. the first function go txt file, other 2 error object doesn't support property or method. when changed 3 create last function goes txt file. can not figure out word use in order make other 2 functions follow txt file in order keyed. the entire code follows private sub addrecord_click() on error goto errhandler module1.nys45uploadfilename = application.getsaveasfilename(filefilter:="textfiles (*.txt), *.txt") if module1.nys45uploadfilename = "false" exit sub ...
Read more

Using django-mptt to get only the categories that have items -

-
sample structure: all uppercase: category mixed case: item root ├── books │   ├── fiction │   │   └── classics │   └── non-fiction ├── clothing └── electronics ├── laptops ├── phones │   ├── apple │   │   ├── iphone 6 │   │   ├── iphone 6 plus │   │   ├── iphone 6s │   │   └── iphone 6s plus │   ├── motorola │   │   ├── moto g4 │   │   ├── moto g4 play │   │   ├── moto g4 plus │   │   └── moto x │   └── samsung └── tablets └── apple i'm trying have index page show "electronics" category. "clothing" category shouldn't show since it's empty , "books" category shouldn't show either since, although has child categories, child categories don't have items. similarly, "electronics" page should show "phones" category. "laptops" category shouldn't show since it's empty , "tablets" category shouldn't show either since...
Read more