Error message when declaring params on system db

e2e_tests/integration/multi-db.spec.js

@@ -130,5 +130,14 @@ describe('Multi database', () => {
       cy.connect('neo4j', Cypress.config('password'))
       cy.dropUser('noroles')
     })
+    it('shows error message when trying to set a parameter on system db', () => {
+      cy.executeCommand(':clear')
+      cy.executeCommand(':use system')
+      cy.executeCommand(':param x => 1')
+      const resultFrame = cy
+        .get('[data-testid="frame"]', { timeout: 10000 })
+        .first()
+      resultFrame.should('contain', 'cannot be declared')
+    })
   }
 })

src/browser/documentation/help/param.jsx

@@ -19,6 +19,7 @@
  */
 
 import React from 'react'
+import ParamsOnSystemDb from './partials/params-on-systemdb'
 const title = 'Set a parameter'
 const subtitle = 'Set a parameter to be sent with queries.'
 const category = 'cypherQueries'
@@ -46,6 +47,7 @@ const content = (
       Cypher query example with a param:
       <code>MATCH (n:Person) WHERE n.name = $name</code>
     </p>
+    <ParamsOnSystemDb />
     <div className='links'>
       <div className='link'>
         <p className='title'>Related</p>

src/browser/documentation/help/params.jsx

@@ -19,6 +19,7 @@
  */
 
 import React from 'react'
+import ParamsOnSystemDb from './partials/params-on-systemdb'
 const title = 'Parameters'
 const subtitle = 'View and set parameters to be sent with queries.'
 const category = 'cypherQueries'
@@ -64,11 +65,12 @@ const content = (
       {` `}
       <code>{`MATCH (n:Person) WHERE n.name = $name`}</code>
     </p>
+    <ParamsOnSystemDb />
     <div className='links'>
       <div className='link'>
         <p className='title'>Related</p>
         <p className='content'>
-          <a help-topic='params'>:help params</a>
+          <a help-topic='param'>:help param</a>
         </p>
       </div>
     </div>

src/browser/documentation/help/partials/params-on-systemdb.jsx

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2002-2019 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+import React from 'react'
+export default function ParamsOnSystemDb () {
+  return (
+    <p>
+      <strong>A note on system database</strong>
+      <br />
+      If you are using a multi-database DBMS, parameters cannot be declared when
+      using the system database. Switch to a different database and declare,
+      then switch back to system database and use them.
+    </p>
+  )
+}

src/shared/modules/commands/helpers/params.js

@@ -21,6 +21,7 @@ import jsonic from 'jsonic'
 import { splitStringOnFirst } from 'services/commandUtils'
 import { update, replace } from 'shared/modules/params/paramsDuck'
 import { collectLambdaValues, parseLambdaStatement } from './lambdas'
+import { SYSTEM_DB } from 'shared/modules/dbMeta/dbMetaDuck'
 
 export const extractParams = param => {
   // early bail, now handled by parser
@@ -77,7 +78,12 @@ export const getParamName = (input, cmdchar) => {
   return parts[0].trim()
 }
 
-export const handleParamsCommand = (action, cmdchar, put) => {
+export const handleParamsCommand = (action, cmdchar, put, targetDb) => {
+  if (targetDb === SYSTEM_DB) {
+    return Promise.reject(
+      new Error('Parameters cannot be declared when using system database.')
+    )
+  }
   const strippedCmd = action.cmd.substr(cmdchar.length)
   const parts = splitStringOnFirst(strippedCmd, ' ')
   const param = parts[1].trim()

src/shared/services/commandInterpreterHelper.js

@@ -131,7 +131,12 @@ const availableCommands = [
     name: 'set-params',
     match: cmd => /^params?\s/.test(cmd),
     exec: function (action, cmdchar, put, store) {
-      return handleParamsCommand(action, cmdchar, put)
+      return handleParamsCommand(
+        action,
+        cmdchar,
+        put,
+        getUseDb(store.getState())
+      )
         .then(res => {
           const params =
             res.type === 'param' ? res.result : getParams(store.getState())
@@ -152,10 +157,11 @@ const availableCommands = [
           if (!action.parentId) {
             put(
               frames.add({
+                useDb: getUseDb(store.getState()),
                 ...action,
                 error: {
                   type: 'Syntax Error',
-                  message: error.message.substring('Error: '.length)
+                  message: error.message.replace(/^Error: /, '')
                 },
                 showHelpForCmd: getParamName(action, cmdchar),
                 type: 'error'