why below error is coming

[ajithamp]

i am using react native android and my code is

componentDidMount() {
var sql = 'INSERT INTO todo(name, completed) VALUES (?, ?)'
var params = ["Create and delete react native android sqlite", 1]
sqlite.exec(sql, params, this.rowCallback, this.completeCallback)
.then((_) => {
alert('row inserted.')
}
)
}

[jbrodriguez]

Hi @ajithamp, did you sqlite.init first ?

Also check that your db structure matches the sql you're sending.

Finally, make sure that you're importing the module only once.

[ajithamp]

hi @jbrodriguez, i did sqlite.init but i dont know exactly what i have to do.If you Don't mind will you please explain clearly because i am new to react native.

And my code is

import React, { Component } from 'react';
import {
  AppRegistry,
  StyleSheet,
  Text,
  Alert,
  View
} from 'react-native';
var sqlite = require('react-native-android-sqlite');

export default class PrepopulatedDatabaseExample extends Component {
  constructor(props) {
    super(props)
    this.state = {
      record: null
    };
    var databaseName = 'app.db';
    sqlite.init(databaseName)
      .then((_) => {
        alert('database initialized.')
      });
  }
componentDidMount() {
var sql = 'INSERT INTO todo(name, completed) VALUES (?, ?)'
var params = ["Create and delete react native android sqlite", 1]
sqlite.exec(sql, params)
.then((_) => {
alert('row inserted.')
} )
}
  success() {
  var sql = 'SELECT * FROM todo WHERE completed = ?';
    var params = [1];
    sqlite.query(sql, params)
      .then((data) => {
        alert('retrieved: ', data)
      } )
  }
  onclick() {
    sqlite.close()
      .then(() => {
        alert('database closed')
      }
      )
  }
  render() {
    return (
      <View style={styles.container}>
        <Text style={styles.welcome} >
          This is an example with sqlite3 and a prepopulated database. Enjoy!
        </Text>
        <Text onPress={this.success}>retiveData</Text>
        <Text onPress={this.onclick} >closeDatabase</Text>
        <Text style={styles.instructions} >
          {this.state.record !== null ? 'Success: ' + this.state.record.name : 'Ajith'}
        </Text>
      </View>
    );
  }
}
const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
  },
  welcome: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
  instructions: {
    textAlign: 'center',
    color: '#333333',
    marginBottom: 5,
  },
});

AppRegistry.registerComponent('PrepopulatedDatabaseExample', () => PrepopulatedDatabaseExample);

[jbrodriguez]

@ajithamp take a look at https://github.com/jbrodriguez/rn-sqlite.

It's the successor to react-native-android-sqlite and it works with the recent React Native versions.

react-native-android-sqlite works as well, but instructions to install it have changed, due to changes in RN.

In any case, in your example,

componentDidMount() {
  success() {
  var sql = 'SELECT * FROM todo WHERE completed = ?';
    var params = [1];
    sqlite.query(sql, params)
      .then((data) => {
        alert('retrieved: ', data)
      } )
  }

you should replace the alert with actually setting the this.state.record, based on the logic you're using, something like

  success() {
  var sql = 'SELECT * FROM todo WHERE completed = ?';
    var params = [1];
    sqlite.query(sql, params)
      .then((data) => {
        this.setState({record: data})
      } )
  }

Also, you need to make sure that the app.db has a table todo with columns name and completed.

[ajithamp]

errorMessage = The callback ${method}() exists in module ${module}, + 'but only one callback may be registered to a function in a native module.';
from here the error is coming.

and DBmanager code is

@ReactMethod
public void query(final String sql, final ReadableArray values, final Callback callback) {
    new GuardedAsyncTask<Void, Void>(getReactApplicationContext()) {
        @Override
        protected void doInBackgroundGuarded(Void ...params) {
            WritableArray data = Arguments.createArray();

            // FLog.w(ReactConstants.TAG, "dbmanager.query.sql=%s", sql);
            // FLog.w(ReactConstants.TAG, "dbmanager.query.values.size()=%d", values.size());

            try {
                data = mDb.query(sql, values);
            } catch(Exception e) {
                FLog.w(ReactConstants.TAG, "Exception in database query: ", e);
                callback.invoke(ErrorUtil.getError(null, e.getMessage()), null);
            }

            callback.invoke(null, data);
        }
    }.execute();
}

[jbrodriguez]

I had that error once , check this issue facebook/react-native#7522 ... it was because I was invoking the callback twice ... not sure what your particular scenario is

[ajithamp]

help me to resolve this error

[jbrodriguez]

It looks like DBManager isn't defined in Java land.

Did you set it up as explained in the README ?

If you're on ReactNative 0.29+, then the instructions have changed (look at manual instructions at https://github.com/jbrodriguez/rn-sqlite)

[ajithamp]

https://github.com/jbrodriguez/rn-sqlite and https://github.com/jbrodriguez/react-native-android-sqlite
i followed steps from both these urls and still it remains the same error.I can't resolve the error any solution there

[jbrodriguez]

You need to follow one set of steps, depending on which RN version you're using.

It certainly looks like a setup issue

What's your output for $ adb logcat | grep 'SQLiteAssetHelper' ?

There should be some lines there.

$ react-native run-android should have some lines beginning with :react-native-android-sqlite. Is that the case ?

[ajithamp]

hi @jbrodriguez thanks, i fixed this issue.One more help i want to know how to throw error.
When invoking the callback twice it throws error implicitly , i want to throw explicitly via alert or console how to do it any idea.
And one more think how to use sqlite delete query.

[jbrodriguez]

@ajithamp You should use the library as a Promise rather than via callbacks.

sqlite.exec(sql, params)
    .then((_) => {
        console.log('row inserted.')
    })
   .catch( error => {
        console.error("something went wrong: " + error)
   })
)

As for delete, just write the appropriate sql string

const sql = 'DELETE FROM todo WHERE completed = 1;'

then send that via sqlite.exec