怎样解决Original must not null

本文介绍了如何解决因Bean缺少SET方法而导致的问题,并提供了一种快速查找相关类的方法——使用Eclipse的快捷键Ctrl+Shift+T进行搜索。

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原因是某个Bean缺少SET方法, 自己一个个找去。

 

 

ctrl+ shift +t Eclipse找类

 

### PostgreSQL Partition Usage and Examples In PostgreSQL, partitions allow the division of large tables into smaller manageable pieces based on specific criteria such as ranges or lists. This approach enhances performance by reducing the amount of data scanned during queries. #### Creating a Partitioned Table To create a partitioned table in PostgreSQL, one can use the `CREATE TABLE` statement with the `PARTITION BY` clause specifying either RANGE or LIST partitioning: ```sql CREATE TABLE measurement ( city_id int not null, logdate date not null, peaktemp int, unitsales int ) PARTITION BY RANGE (logdate); ``` This creates an empty parent table named `measurement`, which will hold no rows itself but instead serves as a container for its child partitions[^3]. #### Adding Partitions After creating the parent table, individual partitions must be added explicitly. For example, adding monthly partitions could look like this: ```sql CREATE TABLE measurement_y2018m07 PARTITION OF measurement FOR VALUES FROM ('2018-07-01') TO ('2018-08-01'); CREATE TABLE measurement_y2018m08 PARTITION OF measurement FOR VALUES FROM ('2018-08-01') TO ('2018-09-01'); ``` Each created table represents a separate physical storage area within the database system while logically being part of the original `measurement` table. #### Querying Partitioned Tables When querying a partitioned table, users do not need to specify any special syntax; standard SQL statements work seamlessly across all defined partitions: ```sql SELECT * FROM measurement WHERE logdate BETWEEN '2018-07-01' AND '2018-07-31'; ``` The query planner automatically determines which partitions contain relevant data and accesses only those segments, improving efficiency significantly compared to scanning entire unpartitioned datasets.
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