add custom prompt to sql db chain

packages/components/nodes/chains/SqlDatabaseChain/SqlDatabaseChain.ts

@@ -1,14 +1,34 @@
 import { ICommonObject, INode, INodeData, INodeParams } from '../../../src/Interface'
 import { SqlDatabaseChain, SqlDatabaseChainInput } from 'langchain/chains/sql_db'
-import { getBaseClasses } from '../../../src/utils'
+import { getBaseClasses, getInputVariables } from '../../../src/utils'
 import { DataSource } from 'typeorm'
 import { SqlDatabase } from 'langchain/sql_db'
 import { BaseLanguageModel } from 'langchain/base_language'
+import { PromptTemplate, PromptTemplateInput } from 'langchain/prompts'
 import { ConsoleCallbackHandler, CustomChainHandler } from '../../../src/handler'
 import { DataSourceOptions } from 'typeorm/data-source'
 
 type DatabaseType = 'sqlite' | 'postgres' | 'mssql' | 'mysql'
 
+const defaultPrompt = `Given an input question, first create a syntactically correct {dialect} query to run, then look at the results of the query and return the answer. Unless the user specifies in his question a specific number of examples he wishes to obtain, always limit your query to at most {top_k} results. You can order the results by a relevant column to return the most interesting examples in the database.
+
+Never query for all the columns from a specific table, only ask for a the few relevant columns given the question.
+
+Pay attention to use only the column names that you can see in the schema description. Be careful to not query for columns that do not exist. Also, pay attention to which column is in which table.
+
+Use the following format:
+
+Question: "Question here"
+SQLQuery: "SQL Query to run"
+SQLResult: "Result of the SQLQuery"
+Answer: "Final answer here"
+
+Only use the tables listed below.
+
+{table_info}
+
+Question: {input}`
+
 class SqlDatabaseChain_Chains implements INode {
     label: string
     name: string
@@ -23,7 +43,7 @@ class SqlDatabaseChain_Chains implements INode {
     constructor() {
         this.label = 'Sql Database Chain'
         this.name = 'sqlDatabaseChain'
-        this.version = 1.0
+        this.version = 2.0
         this.type = 'SqlDatabaseChain'
         this.icon = 'sqlchain.svg'
         this.category = 'Chains'
@@ -64,6 +84,19 @@ class SqlDatabaseChain_Chains implements INode {
                 name: 'url',
                 type: 'string',
                 placeholder: '1270.0.0.1:5432/chinook'
+            },
+            {
+                label: 'Custom Prompt',
+                name: 'customPrompt',
+                type: 'string',
+                description:
+                    'You can provide custom prompt to the chain. This will override the existing default prompt used. See <a target="_blank" href="https://python.langchain.com/docs/integrations/tools/sqlite#customize-prompt">guide</a>',
+                warning:
+                    'Prompt must include 3 input variables: {input}, {dialect}, {table_info}. You can refer to official guide from description above',
+                rows: 4,
+                placeholder: defaultPrompt,
+                additionalParams: true,
+                optional: true
             }
         ]
     }
@@ -72,8 +105,9 @@ class SqlDatabaseChain_Chains implements INode {
         const databaseType = nodeData.inputs?.database as DatabaseType
         const model = nodeData.inputs?.model as BaseLanguageModel
         const url = nodeData.inputs?.url
+        const customPrompt = nodeData.inputs?.customPrompt as string
 
-        const chain = await getSQLDBChain(databaseType, url, model)
+        const chain = await getSQLDBChain(databaseType, url, model, customPrompt)
         return chain
     }
 
@@ -81,8 +115,9 @@ class SqlDatabaseChain_Chains implements INode {
         const databaseType = nodeData.inputs?.database as DatabaseType
         const model = nodeData.inputs?.model as BaseLanguageModel
         const url = nodeData.inputs?.url
+        const customPrompt = nodeData.inputs?.customPrompt as string
 
-        const chain = await getSQLDBChain(databaseType, url, model)
+        const chain = await getSQLDBChain(databaseType, url, model, customPrompt)
         const loggerHandler = new ConsoleCallbackHandler(options.logger)
 
         if (options.socketIO && options.socketIOClientId) {
@@ -96,7 +131,7 @@ class SqlDatabaseChain_Chains implements INode {
     }
 }
 
-const getSQLDBChain = async (databaseType: DatabaseType, url: string, llm: BaseLanguageModel) => {
+const getSQLDBChain = async (databaseType: DatabaseType, url: string, llm: BaseLanguageModel, customPrompt?: string) => {
     const datasource = new DataSource(
         databaseType === 'sqlite'
             ? {
@@ -119,6 +154,14 @@ const getSQLDBChain = async (databaseType: DatabaseType, url: string, llm: BaseL
         verbose: process.env.DEBUG === 'true' ? true : false
     }
 
+    if (customPrompt) {
+        const options: PromptTemplateInput = {
+            template: customPrompt,
+            inputVariables: getInputVariables(customPrompt)
+        }
+        obj.prompt = new PromptTemplate(options)
+    }
+
     const chain = new SqlDatabaseChain(obj)
     return chain
 }