support SHOW CREATE TABLE

sharding-jdbc-core/src/main/java/io/shardingjdbc/core/jdbc/core/statement/ShardingPreparedStatement.java

@@ -35,6 +35,7 @@ import io.shardingjdbc.core.merger.SelectMergeEngine;
 import io.shardingjdbc.core.parsing.parser.context.GeneratedKey;
 import io.shardingjdbc.core.parsing.parser.sql.dal.DALStatement;
 import io.shardingjdbc.core.parsing.parser.sql.dml.insert.InsertStatement;
+import io.shardingjdbc.core.parsing.parser.sql.dql.DQLStatement;
 import io.shardingjdbc.core.parsing.parser.sql.dql.select.SelectStatement;
 import io.shardingjdbc.core.routing.PreparedStatementRoutingEngine;
 import io.shardingjdbc.core.routing.SQLExecutionUnit;
@@ -274,7 +275,7 @@ public final class ShardingPreparedStatement extends AbstractShardingPreparedSta
         if (null != currentResultSet) {
             return currentResultSet;
         }
-        if (1 == routedStatements.size()) {
+        if (1 == routedStatements.size() && routeResult.getSqlStatement() instanceof DQLStatement) {
             currentResultSet = routedStatements.iterator().next().getResultSet();
             return currentResultSet;
         }

sharding-jdbc-core/src/main/java/io/shardingjdbc/core/jdbc/core/statement/ShardingStatement.java

@@ -31,6 +31,7 @@ import io.shardingjdbc.core.merger.SelectMergeEngine;
 import io.shardingjdbc.core.parsing.parser.context.GeneratedKey;
 import io.shardingjdbc.core.parsing.parser.sql.dal.DALStatement;
 import io.shardingjdbc.core.parsing.parser.sql.dml.insert.InsertStatement;
+import io.shardingjdbc.core.parsing.parser.sql.dql.DQLStatement;
 import io.shardingjdbc.core.parsing.parser.sql.dql.select.SelectStatement;
 import io.shardingjdbc.core.routing.SQLExecutionUnit;
 import io.shardingjdbc.core.routing.SQLRouteResult;
@@ -249,7 +250,7 @@ public class ShardingStatement extends AbstractStatementAdapter {
         if (null != currentResultSet) {
             return currentResultSet;
         }
-        if (1 == routedStatements.size()) {
+        if (1 == routedStatements.size() && routeResult.getSqlStatement() instanceof DQLStatement) {
             currentResultSet = routedStatements.iterator().next().getResultSet();
             return currentResultSet;
         }

sharding-jdbc-core/src/main/java/io/shardingjdbc/core/merger/DALMergeEngine.java

@@ -17,9 +17,11 @@
 
 package io.shardingjdbc.core.merger;
 
+import io.shardingjdbc.core.merger.show.ShowCreateTableResultSetMerger;
 import io.shardingjdbc.core.merger.show.ShowDatabasesResultSetMerger;
 import io.shardingjdbc.core.merger.show.ShowOtherResultSetMerger;
 import io.shardingjdbc.core.merger.show.ShowTablesResultSetMerger;
+import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowCreateTableStatement;
 import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowDatabasesStatement;
 import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowTablesStatement;
 import io.shardingjdbc.core.parsing.parser.sql.dal.DALStatement;
@@ -52,6 +54,9 @@ public final class DALMergeEngine implements MergeEngine {
         if (dalStatement instanceof ShowTablesStatement) {
             return new ShowTablesResultSetMerger(shardingRule, resultSets);
         }
+        if (dalStatement instanceof ShowCreateTableStatement) {
+            return new ShowCreateTableResultSetMerger(shardingRule, resultSets);
+        }
         return new ShowOtherResultSetMerger(resultSets.get(0));
     }
 }

sharding-jdbc-core/src/main/java/io/shardingjdbc/core/merger/show/ShowCreateTableResultSetMerger.java

+package io.shardingjdbc.core.merger.show;
+
+import com.google.common.base.Optional;
+import io.shardingjdbc.core.constant.DatabaseType;
+import io.shardingjdbc.core.merger.common.AbstractMemoryResultSetMerger;
+import io.shardingjdbc.core.merger.common.MemoryResultSetRow;
+import io.shardingjdbc.core.parsing.SQLParsingEngine;
+import io.shardingjdbc.core.rule.ShardingRule;
+import io.shardingjdbc.core.rule.TableRule;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Show create table result set merger.
+ *
+ * @author zhangliang
+ */
+public final class ShowCreateTableResultSetMerger extends AbstractMemoryResultSetMerger {
+    
+    private static final Map<String, Integer> LABEL_AND_INDEX_MAP = new HashMap<>(2, 1);
+    
+    private final ShardingRule shardingRule;
+    
+    private final Iterator<MemoryResultSetRow> memoryResultSetRows;
+    
+    static {
+        LABEL_AND_INDEX_MAP.put("Table", 1);
+        LABEL_AND_INDEX_MAP.put("Create Table", 2);
+    }
+    
+    public ShowCreateTableResultSetMerger(final ShardingRule shardingRule, final List<ResultSet> resultSets) throws SQLException {
+        super(LABEL_AND_INDEX_MAP);
+        this.shardingRule = shardingRule;
+        memoryResultSetRows = init(resultSets);
+    }
+    
+    private Iterator<MemoryResultSetRow> init(final List<ResultSet> resultSets) throws SQLException {
+        List<MemoryResultSetRow> result = new LinkedList<>();
+        for (ResultSet each : resultSets) {
+            while (each.next()) {
+                MemoryResultSetRow memoryResultSetRow = new MemoryResultSetRow(each);
+                String tableName = memoryResultSetRow.getCell(1).toString();
+                Optional<TableRule> tableRule = shardingRule.tryFindTableRuleByActualTable(tableName);
+                if (tableRule.isPresent()) {
+                    String logicTableName = tableRule.get().getLogicTable();
+                    memoryResultSetRow.setCell(1, logicTableName);
+                    String createTableDDL = memoryResultSetRow.getCell(2).toString();
+                    SQLParsingEngine sqlParsingEngine = new SQLParsingEngine(DatabaseType.MySQL, createTableDDL, shardingRule);
+                    String actualTableName = sqlParsingEngine.parse().getTables().getSingleTableName();
+                    if (actualTableName.startsWith("`")) {
+                        logicTableName = "`" + logicTableName + "`";
+                    }
+                    memoryResultSetRow.setCell(2, createTableDDL.replaceFirst(actualTableName, logicTableName));
+                    result.add(memoryResultSetRow);
+                }
+            }
+        }
+        if (!result.isEmpty()) {
+            setCurrentResultSetRow(result.get(0));
+        }
+        return result.iterator();
+    }
+    
+    @Override
+    public boolean next() throws SQLException {
+        if (memoryResultSetRows.hasNext()) {
+            setCurrentResultSetRow(memoryResultSetRows.next());
+            return true;
+        }
+        return false;
+    }
+}

sharding-jdbc-core/src/main/java/io/shardingjdbc/core/parsing/parser/dialect/mysql/sql/MySQLShowParser.java

@@ -5,6 +5,7 @@ import io.shardingjdbc.core.parsing.lexer.dialect.mysql.MySQLKeyword;
 import io.shardingjdbc.core.parsing.lexer.token.DefaultKeyword;
 import io.shardingjdbc.core.parsing.parser.clause.TableReferencesClauseParser;
 import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowColumnsStatement;
+import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowCreateTableStatement;
 import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowDatabasesStatement;
 import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowOtherStatement;
 import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowTablesStatement;
@@ -45,9 +46,15 @@ public final class MySQLShowParser extends AbstractShowParser {
             DALStatement result = new ShowColumnsStatement();
             lexerEngine.skipIfEqual(DefaultKeyword.FROM, DefaultKeyword.IN);
             tableReferencesClauseParser.parseSingleTableWithoutAlias(result);
-            lexerEngine.skipIfEqual(DefaultKeyword.FROM, DefaultKeyword.IN);
-            int beginPosition = lexerEngine.getCurrentToken().getEndPosition() - lexerEngine.getCurrentToken().getLiterals().length();
-            result.getSqlTokens().add(new SchemaToken(beginPosition, lexerEngine.getCurrentToken().getLiterals(), result.getTables().getSingleTableName()));
+            if (lexerEngine.skipIfEqual(DefaultKeyword.FROM, DefaultKeyword.IN)) {
+                int beginPosition = lexerEngine.getCurrentToken().getEndPosition() - lexerEngine.getCurrentToken().getLiterals().length();
+                result.getSqlTokens().add(new SchemaToken(beginPosition, lexerEngine.getCurrentToken().getLiterals(), result.getTables().getSingleTableName()));
+            }
+            return result;
+        }
+        if (lexerEngine.skipIfEqual(DefaultKeyword.CREATE) && lexerEngine.skipIfEqual(DefaultKeyword.TABLE)) {
+            DALStatement result = new ShowCreateTableStatement();
+            tableReferencesClauseParser.parseSingleTableWithoutAlias(result);
             return result;
         }
         return new ShowOtherStatement();

sharding-jdbc-core/src/main/java/io/shardingjdbc/core/parsing/parser/dialect/mysql/statement/ShowCreateTableStatement.java

+package io.shardingjdbc.core.parsing.parser.dialect.mysql.statement;
+
+import io.shardingjdbc.core.parsing.parser.sql.dal.DALStatement;
+
+/**
+ * Show create table statement.
+ *
+ * @author zhangliang
+ */
+public final class ShowCreateTableStatement extends DALStatement {
+}

sharding-jdbc-core/src/main/java/io/shardingjdbc/core/routing/router/ParsingSQLRouter.java

@@ -21,13 +21,11 @@ import io.shardingjdbc.core.constant.DatabaseType;
 import io.shardingjdbc.core.jdbc.core.ShardingContext;
 import io.shardingjdbc.core.parsing.SQLParsingEngine;
 import io.shardingjdbc.core.parsing.parser.context.GeneratedKey;
-import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.DescribeStatement;
-import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowColumnsStatement;
 import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowDatabasesStatement;
-import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowOtherStatement;
 import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.ShowTablesStatement;
 import io.shardingjdbc.core.parsing.parser.dialect.mysql.statement.UseStatement;
 import io.shardingjdbc.core.parsing.parser.sql.SQLStatement;
+import io.shardingjdbc.core.parsing.parser.sql.dal.DALStatement;
 import io.shardingjdbc.core.parsing.parser.sql.ddl.DDLStatement;
 import io.shardingjdbc.core.parsing.parser.sql.dml.insert.InsertStatement;
 import io.shardingjdbc.core.parsing.parser.sql.dql.select.SelectStatement;
@@ -125,7 +123,7 @@ public final class ParsingSQLRouter implements SQLRouter {
             routingEngine = new TableBroadcastRoutingEngine(shardingRule, sqlStatement);
         } else if (sqlStatement instanceof ShowDatabasesStatement || sqlStatement instanceof ShowTablesStatement) {
             routingEngine = new DatabaseBroadcastRoutingEngine(shardingRule);
-        } else if (sqlStatement instanceof ShowColumnsStatement || sqlStatement instanceof ShowOtherStatement || sqlStatement instanceof DescribeStatement) {
+        } else if (sqlStatement instanceof DALStatement) {
             routingEngine = new UnicastRoutingEngine(shardingRule, sqlStatement);
         } else if (tableNames.isEmpty() && sqlStatement instanceof SelectStatement) {
             routingEngine = new UnicastRoutingEngine(shardingRule, sqlStatement);