Can't execute multiple selects about react-native-sqlite-storage

[andpor]

Hi Donald

avoid doing stuff on the db open status callback - wait for db instance to be returned and then invoke this.populateDatabase(db)

try removing this.setState(this.state); or recoding this stmt to that.setState(that.state); in populateDatabase.

var that = this is not there by accident

you can either do var that = this or use a bind(this)_ on the method.

[andpor]

otherwise the sample you sent is not complete..where is getService getting called from. What is the param to openDatabase for example?

[andpor]

This code "works" i.e. I see return values from getServices...

React Native is bad in terms of eating up bad references to this it seems...

---

openErrorCallback(message) {

},

populateDatabase(db){
    var that = this;

    db.executeSql('SELECT version_id FROM Version ORDER BY version_id DESC LIMIT 1', [], function(results) {
        console.log("Post version query (success)");
        var len = results.rows.length;
        for (let i = 0; i < len; i++) {
            let row = results.rows.item(i);
            database_current_version = row.version_id;
        }

        that.setState(that.state);

        db.transaction(that.upgradeTables, function() {
            console.log("upgradeTables failed");
        }, function() {
            console.log("upgradeTables success");
            that.getServices(() => {});
        });

    }, function() {
        console.log("Post version query (failed)");
        db.transaction(that.upgradeTables, function() {
            console.log("Upgrade failed");
        }, function() {
            console.log("Upgrade success");
        });
    });


},

upgradeTables(tx) {
    console.log("Database running version "+database_current_version);
    if(database_current_version < 1) {
        tx.executeSql("CREATE TABLE IF NOT EXISTS Version ( " +
            "version_id INTEGER PRIMARY KEY" +
            ");", []);
        tx.executeSql("CREATE TABLE IF NOT EXISTS Service (" +
            "id INTEGER PRIMARY KEY, " +
            "name TEXT" +
            ");", []);
        tx.executeSql("INSERT INTO Version (version_id) VALUES (?)", [1]);
    }
},

addService(callback, obj) {
    var that = this;
    db.transaction(tx).then(() => {
        callback(true);
    });
},

addAccountTransaction(tx, obj) {
    tx.executeSql("INSERT INTO Service (name) VALUES (?)", [obj.name]);
},

getServices(callback) {
    db.executeSql("SELECT id FROM Service", [], function(results) {
        console.log("Got service results "+JSON.stringify(results));
        var len = results.rows.length;
        console.log("len = "+len);
        for (var i = 0; i < len; i++) {
            let row = results.row.item(i);
            console.log("row "+i+" = "+row.id);
        }

        callback(results);
    });
},

executeQuery(query, params) {
    console.log("Executing query "+query);
    return db.executeSql(query, params);
},

executeQueryCallback(query, params, callbackSuccess, callbackFailure) {
    db.executeSql(query, params, callbackSuccess, callbackFailure);
},

executeTransaction(func, callback) {
    console.log("Executing transaction on AuthioDB");
    db.transaction(func).then((results) => {
        callback(true, results);
    }).catch((error) => {
        callback(false);
    });
},

getDbResource() {
    return db;
},


loadAndQueryDB(){
    var that = this;
    that.state.progress.push("Opening database ...");
    that.setState(that.state);
    //database_ready_callback = readyCallback;
    db = SQLite.openDatabase(database_name, database_version, database_displayname, database_size, function() {
        console.log("db opened");
    }, that.openErrorCallback);
    this.populateDatabase(db);
},

[donald-jackson]

Hi Andrzej,

Thanks for taking the time to help. It appears I have misunderstood the purpose of the open callbacks. I thought that the entire nature of this module was asynchronous - ie: you can only use once the open callback has executed, which is why I was doing things in there.

I'll try it again now by just using the populate/etc methods outside of the callback - because my entire structure was basically executing in a chained callback.

Thanks again.

[shanitiwari01]

I follow the below blog to integrate SQLite storage on this blog provided ExecuteQuery function and how to use it because based on promise it handles multiple select queries.

`/**

• Execute sql queries
• @param sql
• @param params
• @returns {resolve} results
  */
  ExecuteQuery = (sql, params = []) => new Promise((resolve, reject) => {
  db.transaction((trans) => {
  trans.executeSql(sql, params, (trans, results) => {
  resolve(results);
  },
  (error) => {
  reject(error);
  });
  });
  });`

https://infinitbility.com/react-native-sqlite-storage-examples-of-query