Fix based on review

Author: KodaiD

core/src/main/java/com/scalar/db/storage/jdbc/JdbcAdmin.java

@@ -710,9 +710,10 @@ public Set<String> getNamespaceTableNames(String namespace) throws ExecutionExce
 
   private Set<String> getNamespaceTableNamesInternal(Connection connection, String namespace)
       throws SQLException {
-    String sql = rdbEngine.getTableNamesInNamespaceSql(namespace);
+    String sql = rdbEngine.getTableNamesInNamespaceSql();
     Set<String> tableNames = new HashSet<>();
     try (PreparedStatement statement = connection.prepareStatement(sql)) {
+      statement.setString(1, namespace);
       try (ResultSet resultSet = statement.executeQuery()) {
         while (resultSet.next()) {
           tableNames.add(resultSet.getString(1));

core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineDb2.java

@@ -585,8 +585,7 @@ public void throwIfCrossPartitionScanOrderingOnBlobColumnNotSupported(
   }
 
   @Override
-  public String getTableNamesInNamespaceSql(String namespace) {
-    return String.format(
-        "SELECT TABNAME FROM SYSCAT.TABLES WHERE TABSCHEMA = '%s' AND TYPE = 'T'", namespace);
+  public String getTableNamesInNamespaceSql() {
+    return "SELECT TABNAME FROM SYSCAT.TABLES WHERE TABSCHEMA = ? AND TYPE = 'T'";
   }
 }

core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineMysql.java

@@ -506,9 +506,7 @@ public void setConnectionToReadOnly(Connection connection, boolean readOnly) thr
   }
 
   @Override
-  public String getTableNamesInNamespaceSql(String namespace) {
-    return "SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = '"
-        + namespace
-        + "'";
+  public String getTableNamesInNamespaceSql() {
+    return "SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = ?";
   }
 }

core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineOracle.java

@@ -453,7 +453,7 @@ public void throwIfAlterColumnTypeNotSupported(DataType from, DataType to) {
   }
 
   @Override
-  public String getTableNamesInNamespaceSql(String namespace) {
-    return String.format("SELECT TABLE_NAME FROM ALL_TABLES WHERE OWNER = '%s'", namespace);
+  public String getTableNamesInNamespaceSql() {
+    return "SELECT TABLE_NAME FROM ALL_TABLES WHERE OWNER = ?";
   }
 }

core/src/main/java/com/scalar/db/storage/jdbc/RdbEnginePostgresql.java

@@ -397,9 +397,7 @@ public String tryAddIfNotExistsToCreateIndexSql(String createIndexSql) {
   }
 
   @Override
-  public String getTableNamesInNamespaceSql(String namespace) {
-    return "SELECT table_name FROM information_schema.tables WHERE table_schema = '"
-        + namespace
-        + "'";
+  public String getTableNamesInNamespaceSql() {
+    return "SELECT table_name FROM information_schema.tables WHERE table_schema = ?";
   }
 }

core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineSqlServer.java

@@ -433,9 +433,7 @@ public Map<String, String> getConnectionProperties(JdbcConfig config) {
   }
 
   @Override
-  public String getTableNamesInNamespaceSql(String namespace) {
-    return "SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = '"
-        + namespace
-        + "'";
+  public String getTableNamesInNamespaceSql() {
+    return "SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = ?";
   }
 }

core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineSqlite.java

@@ -369,10 +369,7 @@ public void setConnectionToReadOnly(Connection connection, boolean readOnly) {
   }
 
   @Override
-  public String getTableNamesInNamespaceSql(String namespace) {
-    return "SELECT name FROM sqlite_master WHERE type='table' AND name LIKE '"
-        + namespace
-        + NAMESPACE_SEPARATOR
-        + "%'";
+  public String getTableNamesInNamespaceSql() {
+    return "SELECT name FROM sqlite_master WHERE type='table' AND name LIKE ?";
   }
 }

core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineStrategy.java

@@ -306,5 +306,5 @@ default void setConnectionToReadOnly(Connection connection, boolean readOnly)
   default void throwIfCrossPartitionScanOrderingOnBlobColumnNotSupported(
       ScanAll scanAll, TableMetadata metadata) {}
 
-  String getTableNamesInNamespaceSql(String namespace);
+  String getTableNamesInNamespaceSql();
 }

integration-test/src/main/java/com/scalar/db/api/DistributedStorageAdminImportTableIntegrationTestBase.java

@@ -255,7 +255,7 @@ public void dropNamespace_ShouldNotDropNonScalarDBTables() throws Exception {
       assertThat(admin.namespaceExists(getNamespace())).isTrue();
       for (TestData testData : testDataList) {
         if (!testData.isImportableTable()) {
-          adminTestUtils.tableExists(getNamespace(), testData.getTableName());
+          assertThat(adminTestUtils.tableExists(getNamespace(), testData.getTableName())).isTrue();
         }
       }
     } finally {

integration-test/src/main/java/com/scalar/db/api/DistributedTransactionAdminImportTableIntegrationTestBase.java

@@ -167,7 +167,7 @@ public void dropNamespace_ShouldNotDropNonScalarDBTables() throws Exception {
       assertThat(admin.namespaceExists(getNamespace())).isTrue();
       for (TestData testData : testDataList) {
         if (!testData.isImportableTable()) {
-          adminTestUtils.tableExists(getNamespace(), testData.getTableName());
+          assertThat(adminTestUtils.tableExists(getNamespace(), testData.getTableName())).isTrue();
         }
       }
     } finally {