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How do I rename a column in a database table using SQL?
...S), you can do it with regular ALTER TABLE statement:
=> SELECT * FROM Test1;
id | foo | bar
----+-----+-----
2 | 1 | 2
=> ALTER TABLE Test1 RENAME COLUMN foo TO baz;
ALTER TABLE
=> SELECT * FROM Test1;
id | baz | bar
----+-----+-----
2 | 1 | 2
...
Postgres unique constraint vs index
...basic but important issue, so I decided to learn by example.
Let's create test table master with two columns, con_id with unique constraint and ind_id indexed by unique index.
create table master (
con_id integer unique,
ind_id integer
);
create unique index master_unique_idx on master (in...
What is the difference between ? and Object in Java generics?
... type of ?. Not everything matches Object, but everything matches ?.
int test1(List<?> l) {
return l.size();
}
int test2(List<Object> l) {
return l.size();
}
List<?> l1 = Lists.newArrayList();
List<Object> l2 = Lists.newArrayList();
test1(l1); // compiles because any...
Error: Could not find or load main class [duplicate]
...lassName_Having_main
suppose you have the following
Package Named: com.test
Class Name: Hello (Having main)
file is located inside "src/com/test/Hello.java"
from outside directory:
$ cd src
$ javac -cp . com/test/*.java
$ java -cp . com/test/Hello
In windows the same thing will be working ...
Eclipse Optimize Imports to Include Static Imports
...
For SpringFramework Tests, I would recommend to add the below as well
org.springframework.test.web.servlet.request.MockMvcRequestBuilders
org.springframework.test.web.servlet.request.MockMvcResponseBuilders
org.springframework.test.web.servlet...
PostgreSQL - max number of parameters in “IN” clause?
...e to the PostgreSQL backend, using Posgresql's JDBC driver 9.1.
This is a test of "delete from x where id in (... 100k values...)" with the postgresql jdbc driver:
Caused by: java.io.IOException: Tried to send an out-of-range integer as a 2-byte value: 100000
at org.postgresql.core.PGStream.Se...
How to keep environment variables when using sudo
...
I have tested this answer for a package under some myPath added to PATH in the .bashrc file (with export clausule). Then sudo PATH=$PATH which package finds the right answer, unlike sudo which package. However, sudo PATH=$PATH packa...
How to sort in mongoose?
I find no doc for the sort modifier. The only insight is in the unit tests:
spec.lib.query.js#L12
17 Answers
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What's the difference between utf8_general_ci and utf8_unicode_ci?
...ks myself.
I created a very simple table with 500,000 rows:
CREATE TABLE test(
ID INT(11) DEFAULT NULL,
Description VARCHAR(20) DEFAULT NULL
)
ENGINE = INNODB
CHARACTER SET utf8
COLLATE utf8_general_ci;
Then I filled it with random data by running this stored procedure:
CREATE PROCEDURE ran...
How do I resolve ClassNotFoundException?
...me.
I use eclipse IDE.
For Class Not Found Exception when running Junit test, try running mvn clean test once. It will compile all the test classes.
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