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This article introduces the knowledge of "what is the design of sql rule engine". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Recently, I used the rule engine to make a simple summary. The rule, to put it bluntly, is, what is the status quo (fact), if (condition), then (action). The rule engine uses the rete algorithm, and I use drools here. In short, I wrap around a core to generate drl files, and the rest are executed by drools.

In order to facilitate the design, the business is uniformly encapsulated with OP (input parameter: param, entity: body, output parameter: res) and executor Exector, so that class can be introduced less. A label table, a rule engine table. There are all kinds of data, variables, instance variables, relational operations, instructions in the tag.

Conditional direct generation

Behavior

Sql padding: give sql to the rules engine. Sql can take parameters, using parameters from the variable library.

$op.setBody

{

"$op.setBody": "select lock_on_active from t_rule_engine where id='$ {id}'"

}

Query array: query sql to get an array.

Executor.sqlList ($op)

{"Executor.sqlList ($op);": "}

Query value: query sql to get the number

Executor.sqlLong ($op)

{"Executor. SqlLong ($op);": "}

Query map: query sql to get map

Executor.sqlMap ($op)

{"Executor. SqlMap ($op);": "}

Query character: query sql to get a string.

Executor.sqlStr ($op)

{"Executor. SqlStr ($op);": "}

Trigger rules: re-execute in the rules file.

Update ($op)

{"update ($op);": "}

Variable copy: put the result of execution into the reference condition.

Executor.paramCopy

{"Executor.paramCopy": ["data", "data1"]} / / assign the value of the query result data to the parameter data1

Variable assignment: assign a constant value to a variable, which can also be a value in the instance variable library.

Executor.let

{"Executor.let": ["data", "cheitemContent"]} / / assign data to cheitemContent in the reference

At present, only "sql fill" and "variable copy" are parameters, and the others are non-parameter actions.

Finally generate the rule file drl

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