Merge pull request #20 from lwhite1/16_lw

16 lw

Author: lwhite1

.gitignore

@@ -10,6 +10,9 @@ data/test.csv
 data/train.csv
 data/train_filter.csv
 
+derby.log
+CoffeeDB/
+
 testfolder/
 
 *.iml

src/main/java/com/github/lwhite1/tablesaw/api/Table.java

@@ -1,5 +1,6 @@
 package com.github.lwhite1.tablesaw.api;
 
+import com.github.lwhite1.tablesaw.io.jdbc.SqlResultSetReader;
 import com.github.lwhite1.tablesaw.table.Projection;
 import com.github.lwhite1.tablesaw.table.Relation;
 import com.github.lwhite1.tablesaw.table.Rows;
@@ -25,6 +26,8 @@
 import org.roaringbitmap.RoaringBitmap;
 
 import java.io.IOException;
+import java.sql.ResultSet;
+import java.sql.SQLException;
 import java.util.*;
 
 import static com.github.lwhite1.tablesaw.sorting.Sort.Order;
@@ -682,4 +685,11 @@ public static Table fromCSV(ColumnType[] types, String fileName) {
     }
     return t;
   }
+
+  /**
+   * Returns a new Table with the given name, and containing the data in the given resultset
+   */
+  public static Table create(ResultSet resultSet, String tableName) throws SQLException {
+    return SqlResultSetReader.read(resultSet, tableName);
+  }
 }

src/main/java/com/github/lwhite1/tablesaw/io/jdbc/SqlResultSetReader.java

@@ -0,0 +1,80 @@
+package com.github.lwhite1.tablesaw.io.jdbc;
+
+import com.github.lwhite1.tablesaw.api.ColumnType;
+import com.github.lwhite1.tablesaw.api.Table;
+import com.github.lwhite1.tablesaw.columns.Column;
+import com.github.lwhite1.tablesaw.io.TypeUtils;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
+
+import java.sql.ResultSet;
+import java.sql.ResultSetMetaData;
+import java.sql.SQLException;
+import java.sql.Types;
+
+/**
+ *  Creates a Table from the result of a SQL query, by passing the jdbc resultset to the constructor
+ */
+public class SqlResultSetReader {
+
+  // Maps from supported SQL types to their Tablesaw 'equivalents'
+  private static final ImmutableMap<Integer, ColumnType> SQL_TYPE_TO_TABLESAW_TYPE =
+      new ImmutableMap.Builder<Integer, ColumnType>()
+          .put(Types.BINARY, ColumnType.BOOLEAN)
+          .put(Types.BOOLEAN, ColumnType.BOOLEAN)
+
+          .put(Types.DATE, ColumnType.LOCAL_DATE)
+          .put(Types.TIME, ColumnType.LOCAL_TIME)
+          .put(Types.TIMESTAMP, ColumnType.LOCAL_DATE_TIME)
+
+          .put(Types.DECIMAL, ColumnType.FLOAT)
+          .put(Types.DOUBLE, ColumnType.FLOAT)
+          .put(Types.FLOAT, ColumnType.FLOAT)
+          .put(Types.NUMERIC, ColumnType.FLOAT)
+          .put(Types.REAL, ColumnType.FLOAT)
+
+          .put(Types.INTEGER, ColumnType.INTEGER)
+          .put(Types.SMALLINT, ColumnType.SHORT_INT)
+          .put(Types.TINYINT, ColumnType.SHORT_INT)
+          .put(Types.BIGINT, ColumnType.LONG_INT)
+          .put(Types.BIT, ColumnType.SHORT_INT)
+
+          .put(Types.CHAR, ColumnType.CATEGORY)
+          .put(Types.LONGVARCHAR, ColumnType.CATEGORY)
+          .put(Types.LONGNVARCHAR, ColumnType.CATEGORY)
+          .put(Types.NCHAR, ColumnType.CATEGORY)
+          .put(Types.NVARCHAR, ColumnType.CATEGORY)
+          .put(Types.VARCHAR, ColumnType.CATEGORY)
+          .build();
+
+  /**
+   * Returns a new table with the given tableName, constructed from the given result set
+   * @throws SQLException
+   */
+  public static Table read(ResultSet resultSet, String tableName) throws SQLException {
+
+    ResultSetMetaData metaData = resultSet.getMetaData();
+    Table table = new Table(tableName);
+
+    // Setup the columns and add to the table
+    for (int i = 1; i <= metaData.getColumnCount(); i++) {
+      String name = metaData.getColumnName(i);
+
+      ColumnType type = SQL_TYPE_TO_TABLESAW_TYPE.get(metaData.getColumnType(i));
+      Preconditions.checkState(type != null,
+          "No column type found for %s as specified for column %s", metaData.getColumnType(i), name);
+
+      Column newColumn = TypeUtils.newColumn(name, type);
+      table.addColumn(newColumn);
+    }
+
+    // Add the rows
+    while (resultSet.next()) {
+      for (int i = 1; i <= metaData.getColumnCount(); i++) {
+        Column column = table.column(i -1); // subtract 1 because results sets originate at 1 not 0
+        column.addCell(resultSet.getString(i));
+      }
+    }
+    return table;
+  }
+}

src/test/java/com/github/lwhite1/tablesaw/io/jdbc/SqlResultSetReaderTest.java

@@ -0,0 +1,63 @@
+package com.github.lwhite1.tablesaw.io.jdbc;
+
+import com.github.lwhite1.tablesaw.api.Table;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.ResultSet;
+import java.sql.Statement;
+
+import static com.github.lwhite1.tablesaw.util.TestDb.*;
+
+/**
+ *  Tests for creating Tables from JDBC result sets using SqlResutSetReader
+ */
+public class SqlResultSetReaderTest {
+
+
+  public static void main(String[] args) throws Exception {
+
+    // Create a named constant for the URL.
+    // NOTE: This value is specific for Java DB.
+    final String DB_URL = "jdbc:derby:CoffeeDB;create=true";
+
+    // Create a connection to the database.
+    Connection conn = DriverManager.getConnection(DB_URL);
+
+    // If the DB already exists, drop the tables.
+    dropTables(conn);
+
+    // Build the Coffee table.
+    buildCoffeeTable(conn);
+
+    // Build the Customer table.
+    buildCustomerTable(conn);
+
+    // Build the UnpaidInvoice table.
+    buildUnpaidOrderTable(conn);
+
+    try (Statement stmt = conn.createStatement()) {
+      String sql;
+      sql = "SELECT * FROM coffee";
+      try (ResultSet rs = stmt.executeQuery(sql)) {
+        Table coffee = SqlResultSetReader.read(rs, "Coffee");
+        System.out.println(coffee.structure().print());
+        System.out.println(coffee.print());
+      }
+
+      sql = "SELECT * FROM Customer";
+      try (ResultSet rs = stmt.executeQuery(sql)) {
+        Table customer = SqlResultSetReader.read(rs, "Customer");
+        System.out.println(customer.structure().print());
+        System.out.println(customer.print());
+      }
+
+      sql = "SELECT * FROM UnpaidOrder";
+      try (ResultSet rs = stmt.executeQuery(sql)) {
+        Table unpaidInvoice = SqlResultSetReader.read(rs, "Unpaid Invoice");
+        System.out.println(unpaidInvoice.structure().print());
+        System.out.println(unpaidInvoice.print());
+      }
+    }
+  }
+}