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What should every developer know about databases? [closed]
...r a nontrivial requirement is not a trivial task. You can't build good SQL tables if you misunderstand the relational model.
Physical data modeling is generally DBMS specific, and doesn't need to be learned in much detail, unless the developer is also the database builder or the DBA. What develope...
Pagination on a list using ng-repeat
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Check out this directive: https://github.com/samu/angular-table
It automates sorting and pagination a lot and gives you enough freedom to customize your table/list however you want.
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Difference between modes a, a+, w, w+, and r+ in built-in open function?
...hat I can now remember! The flow chart in this answer is beautiful and the table in the answer below is great, but if these answers (and others elsewhere) began with this simple point and worked from there, it would help provide a much better mental framework to hang the details on. So thanks. (I'm ...
How to show SQL queries run in the Rails console?
...lain
=> EXPLAIN for: SELECT "categories".* FROM "categories" 0|0|0|SCAN TABLE categories
EXPLAIN for: SELECT "categories_products".* FROM "categories_products" WHERE "categories_products"."category_id" IN (1, 2) 0|0|0|SCAN TABLE categories_products
EXPLAIN for: SELECT "products".* FROM "product...
Can we have multiple “WITH AS” in single sql - Oracle SQL
...nswer above suggests. I was also able to use aliases and columns from both tables in the main query.
– cleberz
Jan 30 '18 at 1:11
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Adding a y-axis label to secondary y-axis in matplotlib
...out messing with matplotlib: just pandas.
Tweaking the original example:
table = sql.read_frame(query,connection)
ax = table[0].plot(color=colors[0],ylim=(0,100))
ax2 = table[1].plot(secondary_y=True,color=colors[1], ax=ax)
ax.set_ylabel('Left axes label')
ax2.set_ylabel('Right axes label')
Ba...
How does virtual inheritance solve the “diamond” (multiple inheritance) ambiguity?
... be only 1 instance of the base A class not 2.
Your type D would have 2 vtable pointers (you can see them in the first diagram), one for B and one for C who virtually inherit A. D's object size is increased because it stores 2 pointers now; however there is only one A now.
So B::A and C::A are...
JPA EntityManager: Why use persist() over merge()?
...nate Session (a.k.a Persistence Context) and is not mapped to any database table row is considered to be in the New (Transient) state.
To become persisted we need to either explicitly call the EntityManager#persist method or make use of the transitive persistence mechanism.
Persistent (Managed)
A...
What's the $unwind operator in MongoDB?
..., consider this array tags : [ "fun" , "good" , "fun" ] as another related table (can't be a lookup/reference table because values has some duplication) named "tags". Remember SELECT generally produces things vertical, so unwind the "tags" is to split() vertically into table "tags".
The end result ...
How do I *really* justify a horizontal menu in HTML+CSS?
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Works with Opera , Firefox, Chrome and IE
ul {
display: table;
margin: 1em auto 0;
padding: 0;
text-align: center;
width: 90%;
}
li {
display: table-cell;
border: 1px solid black;
padding: 0 5px;
}
...