Acceso a Datos

Aplicación que permite: agregar, eliminar y consultar datos de un
servidor SQLite

Author: devcarmelo

09-base de datos/database.py

@@ -0,0 +1,137 @@
+import sys
+
+from PyQt5.QtSql import *
+from PyQt5.QtCore import Qt, QModelIndex
+from PyQt5.QtWidgets import QWidget, QApplication, QVBoxLayout, QPushButton, \
+    QTableWidget, QTableWidgetItem, QMessageBox, QHBoxLayout, QLineEdit, QLabel, QGridLayout
+
+
+class Example(QWidget):
+    def __init__(self, parent=None):
+        super(Example, self).__init__(parent)
+
+        self.table = QTableWidget(0, 3)
+        self.table.setHorizontalHeaderLabels(['ID', 'NOMBRE', 'APELLIDO'])
+        self.table.setAlternatingRowColors(True)
+        self.table.setEditTriggers(QTableWidget.NoEditTriggers)
+        self.table.setSelectionBehavior(QTableWidget.SelectRows)
+        self.table.setSelectionMode(QTableWidget.SingleSelection)
+
+        self.lblID = QLabel("ID:")
+        self.txtID = QLineEdit()
+        self.txtID.setPlaceholderText("Numero identificador unico")
+
+        self.lblName = QLabel("Nombre:")
+        self.txtName = QLineEdit()
+        self.txtName.setPlaceholderText("Nombre de la persona")
+
+        self.lblApellido = QLabel("Apellido:")
+        self.txtApellido = QLineEdit()
+        self.txtApellido.setPlaceholderText("Apellido de la persona")
+
+        grid = QGridLayout()
+        grid.addWidget(self.lblID, 0, 0)
+        grid.addWidget(self.txtID, 0, 1)
+        grid.addWidget(self.lblName, 1, 0)
+        grid.addWidget(self.txtName, 1, 1)
+        grid.addWidget(self.lblApellido, 2, 0)
+        grid.addWidget(self.txtApellido, 2, 1)
+
+        btnCargar = QPushButton('Cargar Datos')
+        btnCargar.clicked.connect(self.cargarDatos)
+
+        btnInsertar = QPushButton('Insertar')
+        btnInsertar.clicked.connect(self.insertarDatos)
+
+        btnEliminar = QPushButton('Eliminar')
+        btnEliminar.clicked.connect(self.eliminarDatos)
+
+        hbx = QHBoxLayout()
+        hbx.addWidget(btnCargar)
+        hbx.addWidget(btnInsertar)
+        hbx.addWidget(btnEliminar)
+
+        vbx = QVBoxLayout()
+        vbx.addLayout(grid)
+        vbx.addLayout(hbx)
+        vbx.setAlignment(Qt.AlignTop)
+        vbx.addWidget(self.table)
+
+        self.setWindowTitle("PyQT :: SQLite Data Access")
+        self.resize(362, 320)
+        self.setLayout(vbx)
+
+    def cargarDatos(self, event):
+        index = 0
+        query = QSqlQuery()
+        query.exec_("select * from person")
+
+        while query.next():
+            ids = query.value(0)
+            nombre = query.value(1)
+            apellido = query.value(2)
+
+            self.table.setRowCount(index + 1)
+            self.table.setItem(index, 0, QTableWidgetItem(str(ids)))
+            self.table.setItem(index, 1, QTableWidgetItem(nombre))
+            self.table.setItem(index, 2, QTableWidgetItem(apellido))
+
+            index += 1
+
+    def insertarDatos(self, event):
+        ids = int(self.txtID.text())
+        nombre = self.txtName.text()
+        apellido = self.txtApellido.text()
+
+        query = QSqlQuery()
+        query.exec_("insert into person values({0}, '{1}', '{2}')".format(ids, nombre, apellido))
+
+    def eliminarDatos(self, event):
+        selected = self.table.currentIndex()
+        if not selected.isValid() or len(self.table.selectedItems()) < 1:
+            return
+
+        ids = self.table.selectedItems()[0]
+        query = QSqlQuery()
+        query.exec_("delete from person where id = " + ids.text())
+
+        self.table.removeRow(selected.row())
+        self.table.setCurrentIndex(QModelIndex())
+
+    def db_connect(self, filename, server):
+        db = QSqlDatabase.addDatabase(server)
+        db.setDatabaseName(filename)
+        if not db.open():
+            QMessageBox.critical(None, "Cannot open database",
+                    "Unable to establish a database connection.\n"
+                    "This example needs SQLite support. Please read the Qt SQL "
+                    "driver documentation for information how to build it.\n\n"
+                    "Click Cancel to exit.", QMessageBox.Cancel)
+            return False
+        return True
+
+    def db_create(self):
+        query = QSqlQuery()
+        query.exec_("create table person(id int primary key, "
+                    "firstname varchar(20), lastname varchar(20))")
+        query.exec_("insert into person values(101, 'Danny', 'Young')")
+        query.exec_("insert into person values(102, 'Christine', 'Holand')")
+        query.exec_("insert into person values(103, 'Lars', 'Gordon')")
+        query.exec_("insert into person values(104, 'Roberto', 'Robitaille')")
+        query.exec_("insert into person values(105, 'Maria', 'Papadopoulos')")
+
+    def init(self, filename, server):
+        import os
+        if not os.path.exists(filename):
+            self.db_connect(filename, server)
+            self.db_create()
+        else:
+            self.db_connect(filename, server)
+
+if __name__ == '__main__':
+    app = QApplication(sys.argv)
+    ejm = Example()
+    ejm.init('datafile', 'QSQLITE')
+    ejm.show()
+    sys.exit(app.exec_())
+