Support PostgreSQL and CockroachDB backends

hugegraph-dist/src/main/java/com/baidu/hugegraph/dist/RegisterUtil.java

@@ -52,7 +52,8 @@ public static void registerBackends() {
         String confFile = "/backend.properties";
         InputStream input = RegisterUtil.class.getClass()
                                         .getResourceAsStream(confFile);
-        E.checkState(input != null, "Can't read file '%s' as stream", confFile);
+        E.checkState(input != null,
+                     "Can't read file '%s' as stream", confFile);
 
         PropertiesConfiguration props = new PropertiesConfiguration();
         props.setDelimiterParsingDisabled(true);
@@ -93,7 +94,8 @@ private static void registerBackend(String backend) {
                 registerPostgresql();
                 break;
             default:
-                throw new HugeException("Unsupported backend type '%s'", backend);
+                throw new HugeException("Unsupported backend type '%s'",
+                                        backend);
         }
     }
 
@@ -171,13 +173,13 @@ public static void registerPalo() {
     public static void registerPostgresql() {
         // Register config
         OptionSpace.register("postgresql",
-                             "com.baidu.hugegraph.backend.store.postgresql.PostgresqlOptions");
+                "com.baidu.hugegraph.backend.store.postgresql.PostgresqlOptions");
         // Register serializer
         SerializerFactory.register("postgresql",
-                                   "com.baidu.hugegraph.backend.store.postgresql.PostgresqlSerializer");
+                "com.baidu.hugegraph.backend.store.postgresql.PostgresqlSerializer");
         // Register backend
         BackendProviderFactory.register("postgresql",
-                                        "com.baidu.hugegraph.backend.store.postgresql.PostgresqlStoreProvider");
+                "com.baidu.hugegraph.backend.store.postgresql.PostgresqlStoreProvider");
     }
 
     public static void registerServer() {

hugegraph-mysql/src/main/java/com/baidu/hugegraph/backend/store/mysql/MysqlTable.java

@@ -120,7 +120,7 @@ protected String engine() {
 
     protected void dropTable(Session session) {
         LOG.debug("Drop table: {}", this.table());
-        String sql = String.format(this.dropTableTemplate, this.table());
+        String sql = this.buildDropTemplate();
         try {
             session.execute(sql);
         } catch (SQLException e) {
@@ -131,7 +131,7 @@ protected void dropTable(Session session) {
 
     protected void truncateTable(Session session) {
         LOG.debug("Truncate table: {}", this.table());
-        String sql = String.format(this.truncateTableTemplate, this.table());
+        String sql = this.buildTruncateTemplate();
         try {
             session.execute(sql);
         } catch (SQLException e) {
@@ -199,6 +199,14 @@ protected String buildDeleteTemplate(List<HugeKeys> idNames) {
         return this.deleteTemplate;
     }
 
+    protected String buildDropTemplate() {
+        return String.format(this.dropTableTemplate, this.table());
+    }
+
+    protected String buildTruncateTemplate() {
+        return String.format(this.truncateTableTemplate, this.table());
+    }
+
     /**
      * Insert an entire row
      */
@@ -211,7 +219,7 @@ public void insert(Session session, MysqlBackendEntry.Row entry) {
             // Create or get insert prepare statement
             insertStmt = session.prepareStatement(template);
             int i = 1;
-            for (Object object : this.insertTemplateObjects(entry)) {
+            for (Object object : this.buildInsertObjects(entry)) {
                 insertStmt.setObject(i++, object);
             }
         } catch (SQLException e) {
@@ -560,7 +568,7 @@ protected void appendPartition(StringBuilder delete) {
         // pass
     }
 
-    protected List<Object> insertTemplateObjects(MysqlBackendEntry.Row entry) {
+    protected List<Object> buildInsertObjects(MysqlBackendEntry.Row entry) {
         List<Object> objects = new ArrayList<>();
         for (Object key : entry.columns().keySet()) {
             objects.add(entry.columns().get(key));

hugegraph-postgresql/src/main/java/com/baidu/hugegraph/backend/store/postgresql/PostgresqlOptions.java

@@ -53,7 +53,7 @@ public static synchronized PostgresqlOptions instance() {
                     "jdbc.url",
                     "The url of database in JDBC format.",
                     disallowEmpty(),
-                    "jdbc:postgresql://127.0.0.1:5432"
+                    "jdbc:postgresql://127.0.0.1:5432/"
             );
 
     public static final ConfigOption<String> JDBC_USERNAME =

hugegraph-postgresql/src/main/java/com/baidu/hugegraph/backend/store/postgresql/PostgresqlSessions.java

@@ -30,7 +30,6 @@ public PostgresqlSessions(HugeConfig config, String database, String store) {
 
     @Override
     protected String buildCreateDatabase(String database) {
-        return String.format("CREATE DATABASE %s ENCODING='UTF-8' " +
-                             "TEMPLATE=template0 LC_COLLATE='C' LC_CTYPE='C';", database);
+        return String.format("CREATE DATABASE %s ENCODING='UTF-8'", database);
     }
 }

hugegraph-postgresql/src/main/java/com/baidu/hugegraph/backend/store/postgresql/PostgresqlTable.java

@@ -47,12 +47,11 @@ protected String engine() {
         return Strings.EMPTY;
     }
 
-
     @Override
-    protected List<Object> insertTemplateObjects(MysqlBackendEntry.Row entry) {
+    protected List<Object> buildInsertObjects(MysqlBackendEntry.Row entry) {
         List<Object> objects = new ArrayList<>();
-        objects.addAll(super.insertTemplateObjects(entry));
-        objects.addAll(super.insertTemplateObjects(entry));
+        objects.addAll(super.buildInsertObjects(entry));
+        objects.addAll(super.buildInsertObjects(entry));
         return objects;
     }