jcamachor commented on a change in pull request #829: Hive JDBC Storage
Handler: Support For Writing Data to JDBC Data Source
URL: https://github.com/apache/hive/pull/829#discussion_r339816176
##########
File path:
jdbc-handler/src/main/java/org/apache/hive/storage/jdbc/dao/GenericJdbcDatabaseAccessor.java
##########
@@ -172,6 +177,67 @@ public int getTotalNumberOfRecords(Configuration conf)
throws HiveJdbcDatabaseAc
}
}
+ public RecordWriter getRecordWriter(TaskAttemptContext context)
+ throws IOException {
+ Configuration conf = context.getConfiguration();
+ Connection conn = null;
+ PreparedStatement ps = null;
+ String dbProductName =
conf.get(JdbcStorageConfig.DATABASE_TYPE.getPropertyName()).toUpperCase();
+ String tableName = conf.get(JdbcStorageConfig.TABLE.getPropertyName());
+
+ if (tableName == null || tableName.isEmpty()) {
+ throw new IllegalArgumentException("Table name should be defined");
+ }
+
+ String[] columnNames = conf.get(serdeConstants.LIST_COLUMNS).split(",");
+
+ try {
+ initializeDatabaseConnection(conf);
+ conn = dbcpDataSource.getConnection();
+ ps = conn.prepareStatement(
+ constructQuery(tableName, columnNames, dbProductName));
+ return new org.apache.hadoop.mapreduce.lib.db.DBOutputFormat()
+ .new DBRecordWriter(conn, ps);
+ } catch (Exception e) {
+ cleanupResources(conn, ps, null);
+ throw new IOException(e.getMessage());
+ }
+ }
+
+ /**
+ * Constructs the query used as the prepared statement to insert data.
+ *
+ * @param table
+ * the table to insert into
+ * @param columnNames
+ * the columns to insert into.
+ * @param dbProductName
+ * type of database
+ *
+ */
+ public String constructQuery(String table, String[] columnNames, String
dbProductName) {
+ if(columnNames == null) {
+ throw new IllegalArgumentException("Column names may not be null");
+ }
+
+ StringBuilder query = new StringBuilder();
+ query.append("INSERT INTO ").append(table).append(" VALUES (");
+
+ for (int i = 0; i < columnNames.length; i++) {
+ query.append("?");
+ if(i != columnNames.length - 1) {
+ query.append(",");
+ }
+ }
+
+ if (!dbProductName.equals(DatabaseType.DERBY.toString()) &&
!dbProductName.equals(DatabaseType.ORACLE.toString())
Review comment:
Specific logic for different database products should not be handled with if
clauses over here. Instead, you can create a method with default implementation
for most common case in this generic accessor and override behavior if needed
on a per-accessor basis (see e.g., `addLimitToQuery` method for an example,
which is overridden for Oracle accessor, MySQL, etc).
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