Well, you are of course NOT limited to one specific schema (Why should this be exactly dnk?) and QGIS loads default styles for tables in whatever schema (but first of all I strongly recommend to the latest QGIS Versions 2.18.22 LTR and/or 3.2 by Aug. 6th, 2018).

I have a layer plz_by_31468 stored in a schema plz (without loss of generality), geometry column is geom (Postal code regions in Bavaria, Germany). If e.g. in QGIS 3.2 under Layer|Properties|Style|Style|Save Style|Save in database (postgres)

you save the style with e.g. the following settings:

you create the following entry in your public.layer_styles table:

and this style definitely loads per default (at least in the two latest versions mentioned above that I have access to).

If you have created the public.layer_styles table manually, make sure that the tables schema is in the f_table_name, that you have no misspellings in the f_table_name column and that the useasdefault column is set to some boolean True (t, 1, ... should work also, cp. https://www.postgresql.org/docs/10/static/datatype-boolean.html for valid representations of boolean type in PostgreSQL) only for the style you want to load as default and False for any other.

Well, you are of course NOT limited to one specific schema (Why should this be exactly dnk?) besides public and QGIS loads default styles for whatever schema your tables are stored in (but first of all I strongly recommend to the latest QGIS Versions 2.18.22 LTR and/or 3.2 by Aug. 6th, 2018).

I have a layer plz_by_31468 stored in a schema plz (without loss of generality), geometry column is geom (Postal code regions in Bavaria, Germany). If e.g. in QGIS 3.2 under Layer|Properties|Style|Style|Save Style|Save in database (postgres)

you save the style with e.g. the following settings:

you create the following entry in your public.layer_styles table:

and this style definitely loads per default (at least in the two latest versions mentioned above that I have access to).

If you have created the public.layer_styles table manually, make sure that the tables schema is in the f_table_name, that you have no misspellings in the f_table_name column and that the useasdefault column is set to some boolean True (t, 1, ... should work also, cp. https://www.postgresql.org/docs/10/static/datatype-boolean.html for valid representations of boolean type in PostgreSQL) only for the style you want to load as default and False for any other.

Well, you are of course NOT limited to one specific schema (Why should this be exactly dnk?) and QGIS loads default styles for tables in whatever schema (but first of all I strongly recommend to the latest QGIS Versions 2.18.22 LTR and/or 3.2 by Aug. 6th, 2018).

If e.g. in QGIS 3.2 under Layer|Properties|Style|Style|Save Style|Save in database (postgres)

you save the style with e.g. the following settings:

you create the following entry in your public.layer_styles table:

and this style definitely loads per default (at least in the two latest versions above that I have access to)

If you have created the public.layer_styles table manually, make sure that the tables schema is in the f_table_name, that you have no misspellings in the f_table_name column and that the useasdefault column is set to some boolean True (t, 1, ... should work also, cp. https://www.postgresql.org/docs/10/static/datatype-boolean.html for valid representations of boolean type in PostgreSQL) only for the style you want to load as default and False for any other.

Well, you are of course NOT limited to one specific schema (Why should this be exactly dnk?) and QGIS loads default styles for tables in whatever schema (but first of all I strongly recommend to the latest QGIS Versions 2.18.22 LTR and/or 3.2 by Aug. 6th, 2018).

I have a layer plz_by_31468 stored in a schema plz (without loss of generality), geometry column is geom (Postal code regions in Bavaria, Germany). If e.g. in QGIS 3.2 under Layer|Properties|Style|Style|Save Style|Save in database (postgres)

you save the style with e.g. the following settings:

you create the following entry in your public.layer_styles table:

and this style definitely loads per default (at least in the two latest versions mentioned above that I have access to).

If you have created the public.layer_styles table manually, make sure that the tables schema is in the f_table_name, that you have no misspellings in the f_table_name column and that the useasdefault column is set to some boolean True (t, 1, ... should work also, cp. https://www.postgresql.org/docs/10/static/datatype-boolean.html for valid representations of boolean type in PostgreSQL) only for the style you want to load as default and False for any other.