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How can I make a JPA OneToOne relation lazy
... a proxy object or NULL and it can't determine that by looking at its base table's columns due to one-to-one normally being mapped via shared PK, so it has to be eagerly fetched anyway making proxy pointless. Here's a more detailed explanation.
many-to-one associations (and one-to-many, obviously) d...
Why can't C compilers rearrange struct members to eliminate alignment padding? [duplicate]
...it (for example: a foreign library, a file on disc, network data, CPU page tables, ...). In such a case the binary structure of data is also defined in a place inaccessible to the compiler, so reordering the struct fields would create a data type that is inconsistent with the other definitions. For ...
What is the optimal length for user password salt? [closed]
...ices for how long the salt should be? I'll be storing the salt in my user table, so I would like the best tradeoff between storage size and security. Is a random 10 character salt enough? Or do I need something longer?
...
PostgreSQL - max number of parameters in “IN” clause?
... possible if the inputs are all scalars (no RowExprs) and there is a
* suitable array type available. If not, we fall back to a boolean
* condition tree with multiple copies of the lefthand expression.
* Also, any IN-list items that contain Vars are handled as separate
* boolean conditions, bec...
Return number of rows affected by UPDATE statements
...
CREATE PROCEDURE UpdateTables
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
DECLARE @RowCount1 INTEGER
DECLARE @RowCount2 INTEGER
DECLARE @RowCount3...
Why use multiple columns as primary keys (composite primary key)
...
Another example of compound primary keys are the usage of Association tables. Suppose you have a person table that contains a set of people and a group table that contains a set of groups. Now you want to create a many to many relationship on person and group. Meaning each person can belong t...
Any way to declare a size/partial border to a box?
...g...
Partly underlined text elements can easily achieved by using display:table or display:inline-block
(I just don't use display:inline-block because, yeah you know, the awkward 4px-gap).
Textual Elements
h1 {
border-bottom: 1px solid #f00;
display: table;
}
<h1>Foo is not equ...
How to create id with AUTO_INCREMENT on Oracle?
...acle 11g. However, you can model it easily with a sequence and a trigger:
Table definition:
CREATE TABLE departments (
ID NUMBER(10) NOT NULL,
DESCRIPTION VARCHAR2(50) NOT NULL);
ALTER TABLE departments ADD (
CONSTRAINT dept_pk PRIMARY KEY (ID));
CREATE SEQUENCE dept_seq STA...
Group by multiple columns in dplyr, using string vector input
...e
df2 <- plyr::ddply(data, columns, plyr::summarize, value=mean(value))
table(df1 == df2, useNA = 'ifany')
## TRUE
## 27
The output from your example question is as expected (see comparison to plyr above and output below):
# A tibble: 9 x 3
# Groups: asihckhdoydkhxiydfgfTgdsx [?]
asihck...
Find rows that have the same value on a column in MySQL
In a [member] table, some rows have the same value for the email column.
8 Answers
8...