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搭建高可用mongodb集群（四）—— 分片 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...需要分片的集合和片键
db.runCommand( { shardcollection : "testdb.table1",key : {id: 1} } )
我们设置testdb的 table1 表需要分片，根据 id 自动分片到 shard1 ，shard2，shard3 上面去。要这样设置是因为不是所有mongodb 的数据库和表 都需要分片！
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How to change the default charset of a MySQL table?
There is a MySQL table which has this definition taken from SQLYog Enterprise :
5 Answers
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How do I execute inserts and updates in an Alembic upgrade script?
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This answer assumes you are using declarative (as opposed to class-Mapper-Table or core) to define your models. It should be relatively straightforward to adapt this to the other forms.
Note that Alembic provides some basic data functions: op.bulk_insert() and op.execute(). If the operations are ...
Reset auto increment counter in postgres
I would like to force the auto increment field of a table to some value, I tried with this:
12 Answers
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How should a model be structured in MVC? [closed]
...n Object-Relational Mapping technique (ORM) nor an abstraction of database tables. Anyone who tells you otherwise is most likely trying to 'sell' another brand-new ORM or a whole framework.
What a model is:
In proper MVC adaptation, the M contains all the domain business logic and the Model Layer ...
Liquibase lock - reasons?
...inst the database helps.
Or you can simply drop the DATABASECHANGELOGLOCK table, it will be recreated.
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Can you create nested WITH clauses for Common Table Expressions?
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While not strictly nested, you can use common table expressions to reuse previous queries in subsequent ones.
To do this, the form of the statement you are looking for would be
WITH x AS
(
SELECT * FROM MyTable
),
y AS
(
SELECT * FROM x
)
SELECT * FROM y
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PHP: exceptions vs errors?
... ul.code li.line {
color : red;
}
table.trace {
width : 100%;
border-collapse : collapse;
border : solid 1px black;
}
table.thead tr {
background : rgb(240,240,240);
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How do I use cascade delete with SQL Server?
I have 2 tables: T1 and T2, they are existing tables with data. We have a one to many relationship between T1 and T2. How do I alter the table definitions to perform cascading delete in SQL Server when a record from T1 is deleted, all associated records in T2 also deleted.
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Select random row from a sqlite table
I have a sqlite table with the following schema:
7 Answers
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