fix rename file MyDb.java -> MyDB.java to match class name

1 files changed, 103 insertions, 0 deletions

diff --git a/src/com.example.portfolio2/com/example/portfolio2/MyDB.java b/src/com.example.portfolio2/com/example/portfolio2/MyDB.java
new file mode 100644
index 0000000..a6c3cb7
--- /dev/null
+++ b/src/com.example.portfolio2/com/example/portfolio2/MyDB.java
@@ -0,0 +1,103 @@
+package com.example.portfolio2;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.ArrayList;
+
+/// standard Database configuration provided at lecture
+class MyDB {
+
+	/// foo
+	Connection conn = null;
+
+	/// foo
+	MyDB() {
+		if (conn == null) open();
+	}
+
+	/// foo
+	public void open() {
+		try {
+			String url = "jdbc:sqlite:identifier.sqlite";
+			conn = DriverManager.getConnection(url);
+		} catch (SQLException e) {
+			System.out.println("cannot open");
+			if (conn != null) close();
+			throw new RuntimeException(e);
+		}
+		;
+	}
+
+	/// foo
+	public void close() {
+		try {
+			if (conn != null) conn.close();
+		} catch (SQLException e) {
+			throw new RuntimeException(e);
+		}
+		conn = null;
+	}
+
+	/// foo
+	/// @param sql  foo
+	public void cmd(String sql) {
+		if (conn == null) open();
+		if (conn == null) {
+			System.out.println("No connection");
+			return;
+		}
+		Statement stmt = null;
+		try {
+			stmt = conn.createStatement();
+			stmt.executeUpdate(sql);
+		} catch (SQLException e) {
+			System.out.println("Error in statement " + sql);
+			throw new RuntimeException(e);
+		}
+		try {
+			if (stmt != null) {
+				stmt.close();
+			}
+		} catch (SQLException e) {
+			System.out.println("Error in statement " + sql);
+			throw new RuntimeException(e);
+		}
+	}
+
+	/// foo
+	/// @param query  foo
+	/// @param fld    foo
+	/// @return       foo
+	public ArrayList<String> query(String query, String fld) {
+		ArrayList<String> res = new ArrayList<>();
+		if (conn == null) open();
+		if (conn == null) {
+			System.out.println("No connection");
+			throw new RuntimeException("No connection");
+		}
+		Statement stmt = null;
+		try {
+			stmt = conn.createStatement();
+			ResultSet rs = stmt.executeQuery(query);
+			while (rs.next()) {
+				String name = rs.getString(fld);
+				res.add(name);
+			}
+		} catch (SQLException e) {
+			System.out.println("Error in statement " + query + " " + fld);
+			throw new RuntimeException(e);
+		}
+		try {
+			if (stmt != null) {
+				stmt.close();
+			}
+		} catch (SQLException e) {
+			System.out.println("Error in statement " + query + " " + fld);
+			throw new RuntimeException(e);
+		}
+		return res;
+	}
+}