SQOOP-1405: Add arg to enable SQL Server identity insert on export

src/docs/user/connectors.txt

@@ -125,6 +125,8 @@ List of all extra arguments supported by Microsoft SQL Connector is shown below:
 `----------------------------------------`---------------------------------------
 Argument                                 Description
 ---------------------------------------------------------------------------------
++\--identity-insert                      Set IDENTITY_INSERT to ON before \
+                                         export insert.
 +\--non-resilient+                       Don't attempt to recover failed \
                                          export operations.
 +\--schema <name>+                       Scheme name that sqoop should use. \
@@ -133,6 +135,15 @@ Argument                                 Description
                                          data movement.
 ---------------------------------------------------------------------------------
 
+Allow identity inserts
+^^^^^^^^^^^^^^^^^^^^^^
+
+You can allow inserts on columns that have identity. For example:
+
+----
+$ sqoop export ... --export-dir custom_dir --table custom_table -- --identity-insert
+----
+
 Non-resilient operations
 ^^^^^^^^^^^^^^^^^^^^^^^^
 

src/java/org/apache/sqoop/manager/SQLServerManager.java

@@ -60,6 +60,11 @@ public class SQLServerManager
   // Option set in extra-arguments to disable resiliency and use default mode
   public static final String NON_RESILIENT_OPTION = "non-resilient";
 
+  // Option to allow inserts on identity columns
+  public static final String IDENTITY_INSERT = "identity-insert";
+  public static final String IDENTITY_INSERT_PROP =
+      "org.apache.sqoop.manager.sqlserver.table.identity";
+
   // driver class to ensure is loaded when making db connection.
   private static final String DRIVER_CLASS =
       "com.microsoft.sqlserver.jdbc.SQLServerDriver";
@@ -77,6 +82,11 @@ public class SQLServerManager
    */
   private String tableHints;
 
+  /**
+   * Whether to allow identity inserts.
+   */
+  private boolean identityInserts;
+
   public SQLServerManager(final SqoopOptions opts) {
     super(DRIVER_CLASS, opts);
 
@@ -159,6 +169,10 @@ public void exportTable(com.cloudera.sqoop.manager.ExportJobContext context)
     if (tableHints != null) {
       configuration.set(TABLE_HINTS_PROP, tableHints);
     }
+
+    // Propagate whether to allow identity inserts to job
+    configuration.setBoolean(IDENTITY_INSERT_PROP, identityInserts);
+
     JdbcExportJob exportJob;
     if (isNonResilientOperation()) {
       exportJob = new JdbcExportJob(context, null, null,
@@ -286,6 +300,8 @@ void parseExtraArgs(String[] args) throws ParseException {
 
       this.tableHints = hints;
     }
+
+    identityInserts = cmdLine.hasOption(IDENTITY_INSERT);
   }
 
   /**
@@ -307,6 +323,10 @@ private RelatedOptions getExtraOptions() {
       .withDescription("Optional table hints to use")
       .withLongOpt(TABLE_HINTS).create());
 
+    extraOptions.addOption(OptionBuilder
+      .withDescription("Allow identity inserts")
+      .withLongOpt(IDENTITY_INSERT).create());
+
     return extraOptions;
   }
 

src/java/org/apache/sqoop/mapreduce/SQLServerExportDBExecThread.java

@@ -123,6 +123,11 @@ protected void executeStatement(PreparedStatement stmt,
   protected String getInsertStatement(int numRows) {
     StringBuilder sb = new StringBuilder();
 
+    if (getConf().getBoolean(SQLServerManager.IDENTITY_INSERT_PROP, false)) {
+      LOG.info("Enabling identity inserts");
+      sb.append("SET IDENTITY_INSERT ").append(tableName).append(" ON ");
+    }
+
     sb.append("INSERT INTO " + tableName + " ");
 
     String tableHints = getConf().get(SQLServerManager.TABLE_HINTS_PROP);

src/java/org/apache/sqoop/mapreduce/sqlserver/SqlServerExportBatchOutputFormat.java

@@ -62,6 +62,11 @@ public SqlServerExportBatchRecordWriter(TaskAttemptContext context)
     protected String getInsertStatement(int numRows) {
       StringBuilder sb = new StringBuilder();
 
+      if (getConf().getBoolean(SQLServerManager.IDENTITY_INSERT_PROP, false)) {
+        LOG.info("Enabling identity inserts");
+        sb.append("SET IDENTITY_INSERT ").append(tableName).append(" ON ");
+      }
+
       sb.append("INSERT INTO " + tableName + " ");
 
       String tableHints = getConf().get(SQLServerManager.TABLE_HINTS_PROP);