使用spring data jpa从db过滤和检索数据

Question

I am using reactjs as a front-end and spring boot as back-end. I am using spring data jpa.

Here is my dilemma.. and I know the way I have written the logic is inefficient and would like to know and understand a better approach to address the issue.

Lets say there are thousands of records in the db and I need to retrieve them constantly and instantly (if possible)

I have 2 fields in UI. One is String and the other is Integer.

Name (String) SomeKindOfId (int) ------------- -------------------

I have to filter the records only after 3 characters are entered in Name field and/or in SomeKindOfId field.

How can I achieve this efficiently?

currently, I have

findAllByNameAndSomeKindOfId("%"+name+"%","%"+String.valueOf(SomeKindOfId)+"%")

in service

and something like this in repository class

Query("Select u from SomeTable u where u.name = :name and CAST(u.someKindOfId As string) like :someKindOfId")
List<CdoDimStPortfolio> findAllByEntityStatusAndDealName(@Param("name") String name,
        @Param("someKindOfId") String someKindOfId);

The reason I am using casting is because I have someKindOfId as int in database

Answer 1

The best way to make efficient database queries is to create indexes by the values you are going to search.

You could create a index "name" and "someKindOfId" and the search for those values would be immediate, because it's like in a book, if you search a chapter page by page you will take much longer than if you go to the index and search for it.

For example for postgresql:

https://www.postgresql.org/docs/9.1/sql-createindex.html

CREATE INDEX constructs an index on the specified column(s) of the specified table. Indexes are primarily used to enhance database performance