Presenting recommendations can be split up in to two main sections: Feature extraction Recommendation Feature extraction is very specific to the object being recommended. For music, for example, some features of the object might be the frequency response of the song, the power, the genre, etc. The features for the users might be age, location, … Read more
The error message pops up when none of the schemas in your search_path can be found. Either it is misconfigured. What do you get for this? SHOW search_path; Or you deleted the public schema from your standard system database template1. You may have been connected to the wrong database when you ran drop schema public … Read more
A schema is a blueprint of the database which specifies what fields will be present and what would be their types. For example an employee table will have an employee_ID column represented by a string of 10 digits and an employee_Name column with a string of 45 characters. Data model is a high level design … Read more
LDAP can be considered a database. But I’m assuming that you mean SQL databases. LDAP data stores are for systems with high number of reads compared to writes. While other databases such as SQL stores are designed for transactional data usage (high read and writes). This is why LDAP is a directory protocol. It’s well … Read more
No, there is no way to change the default behavior of NULLS FIRST and NULLS LAST: NULLS LAST is the default for ascending order, and NULLS FIRST is the default for descending order. I can’t prove it’s impossible to change, but I cannot find such a feature in the places it is most likely to … Read more
clojure-contrib has an sql library which is a thin wrapper around JDBC (java.sql.DriverManager). The test file that comes with it has some examples of its usage.
You could do this in PL/SQL: declare l_nullable user_tab_columns.nullable%type; begin select nullable into l_nullable from user_tab_columns where table_name=”MYTABLE” and column_name=”MYCOLUMN”; if l_nullable=”N” then execute immediate ‘alter table mytable modify (mycolumn null)’; end if; end;
I don’t think there’s a maximum amount of work that can be performed in a transaction. Data keeps getting added to the table files, and eventually the transaction either commits or rolls backs: AIUI this result gets stored in pg_clog; if it rolls back, the space will eventually be reclaimed by vacuum. So it’s not … Read more
The use keyword is what you need: $id = 3; DB::transaction(function($id) use ($id) { DB::table(‘users’)->where(‘id’, ‘=’, $id)->get(); }); For PHP 7 (untested, edited as requested by the answer below): $id = 3; DB::transaction(function() use ($id) { DB::table(‘users’)->where(‘id’, ‘=’, $id)->get(); });