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How to make MySQL handle UTF-8 properly
...til just recently), and not complete (does not discuss correctly inserting/selecting utf8-encoded data, nor displaying in html).
– Rick James
Jan 20 '16 at 3:28
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C++ protobuf使用入门实例 - C/C++ - 清泛网 - 专注C/C++及内核技术
...singleton enumeration to represent the null value for the
// `Value` type union.
//
// The JSON representation for `NullValue` is JSON `null`.
enum TestNullValue {
// Null value.
NULL_VALUE = 0;
}
// `ListValue` is a wrapper around a repeated field of values.
//
// The JSON represen...
Integrating MySQL with Python in Windows
...e essentials version because it doesnt contain the C libraries.
Be sure to select a custom install, and mark the development tools / libraries for installation as that is not done by default. This is needed to get the C header files.
You can verify you have done this correctly by looking in your ins...
Reorder / reset auto increment primary key
...riable, this is okay: SET @a = @a + 1; For other statements, such as SELECT, you might get the results you expect, but this is not guaranteed. In the following statement, you might think that MySQL will evaluate @a first and then do an assignment second: SELECT @a, @a:=@a+1, ...; However...
How do I specify unique constraint for multiple columns in MySQL?
... For those people using MySQL workbench: go to the Indexes tab and select UNIQUE as your type. Give your index a name and check the appropriate columns under the section "Index Columns"
– Pakman
Jun 3 '13 at 20:42
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Auto Generate Database Diagram MySQL [closed]
...the beginning of every project. Is there a tool out there that will let me select specific tables and then create a database diagram for me based on a MySQL database? Preferably it would allow me to edit the diagram afterward since none of the foreign keys are set...
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Create a new database with MySQL Workbench
...CE.
You launch MySQL Workbench.
From Menu Bar click on Database and then select "Connect to Database"
It by default showing you default settings other wise you choose you host name, user name and password. and click to ok.
As in above define that you should click write on existing database but if ...
Check if table exists without using “select from”
Is there a way to check if a table exists without selecting and checking values from it?
17 Answers
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How do I rename a column in a database table using SQL?
...any other RDBMS), 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
...
Is there any performance gain in indexing a boolean field?
...
It depends on the actual queries and the selectivity of the index/query combination.
Case A: condition WHERE isok = 1 and nothing else there:
SELECT *
FROM tableX
WHERE isok = 1
If the index is selective enough (say you have 1M rows and only 1k have isok = 1), ...