大约有 6,100 项符合查询结果（耗时：0.0314秒） [XML]
Smallest data URI image possible for a transparent image
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After playing around with different transparent GIFs, some are unstable and cause CSS glitches. For example, if you have an <img> and you use the tiniest transparent GIF possible, it works fine, however, if you then want your transparent GIF to have a background-image, then this is im...
How can I make SQL case sensitive string comparison on MySQL?
...y I have had luck in using varbinary instead of varchar for a field in ut8 table. HTH
– Andrew T
Jan 5 '15 at 19:54
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show 4 more comments
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MySQL error 1449: The user specified as a definer does not exist
... ALTER statements
SELECT CONCAT("ALTER DEFINER=`youruser`@`host` VIEW ",
table_name, " AS ", view_definition, ";")
FROM information_schema.views
WHERE table_schema='your-database-name';
Copy and run the ALTER statements
How to change the definer for stored procedures
Example:
UPDATE `mysql`...
MySql Table Insert if not exist otherwise update
...ould not change. You do need to include all of the other columns from your table. You can use the VALUES() function to make sure the proper values are used when updating the other columns.
Here is your update re-written using the proper INSERT ... ON DUPLICATE KEY UPDATE syntax for MySQL:
INSERT I...
How to re-create database for Entity Framework?
... new project and create a new mdf. The mdf does not have to match your old tables, because were going to delete it. So create or copy an old one to the correct folder.
Open it in server explorer [double click the mdf from solution explorer]
Delete it in server explorer
Delete it from solution explor...
Relative frequencies / proportions with dplyr
...our depending on the version of dplyr:
dplyr 0.7.1: returns an ungrouped table: you need to group again by am
dplyr < 0.7.1: returns a grouped table, so no need to group again, although you might want to ungroup() for later manipulations
dplyr 0.7.1
mtcars %>%
count(am, gear) %>%
g...
How to check if a Constraint exists in Sql server?
...QUE, PRIMARY KEY, and/or FOREIGN KEY
SELECT *
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE CONSTRAINT_NAME='XYZ'
--Returns one row for each FOREIGN KEY constrain
SELECT *
FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS
WHERE CONSTRAINT_NAME='XYZ'
--Returns one row for eac...
What is the advantage to using bloom filters?
...esenting sets, such as
self-balancing binary search trees,
tries, hash tables, or simple arrays
or linked lists of the entries. Most
of these require storing at least the
data items themselves, which can
require anywhere from a small number
of bits, for small integers, to an
arbitrar...
Combining “LIKE” and “IN” for SQL Server [duplicate]
...y, the IN statement creates a series of OR statements... so
SELECT * FROM table WHERE column IN (1, 2, 3)
Is effectively
SELECT * FROM table WHERE column = 1 OR column = 2 OR column = 3
And sadly, that is the route you'll have to take with your LIKE statements
SELECT * FROM table
WHERE column...
How to map a composite key with JPA and Hibernate?
...// getters, setters
}
The IdClass annotation maps multiple fields to the table PK.
With EmbeddedId
The class for the composite primary key could look like (could be a static inner class):
@Embeddable
public class TimePK implements Serializable {
protected Integer levelStation;
protecte...