diff --git a/core/src/integration-test/java/com/scalar/db/storage/jdbc/JdbcAdminImportTestUtils.java b/core/src/integration-test/java/com/scalar/db/storage/jdbc/JdbcAdminImportTestUtils.java
index b33d72f47b..531fe9c645 100644
--- a/core/src/integration-test/java/com/scalar/db/storage/jdbc/JdbcAdminImportTestUtils.java
+++ b/core/src/integration-test/java/com/scalar/db/storage/jdbc/JdbcAdminImportTestUtils.java
@@ -362,12 +362,20 @@ private LinkedHashMap<String, String> prepareColumnsForOracle() {
     columns.put("col19", "TIMESTAMP"); // override to TIME
     columns.put("col20", "TIMESTAMP WITH TIME ZONE");
     columns.put("col21", "TIMESTAMP WITH LOCAL TIME ZONE");
+    columns.put("col22", "NUMBER(1)"); // override to BOOLEAN
     return columns;
   }
 
   private Map<String, DataType> prepareOverrideColumnsTypeForOracle() {
     return ImmutableMap.of(
-        "col16", DataType.TIME, "col17", DataType.TIMESTAMP, "col19", DataType.TIME);
+        "col16",
+        DataType.TIME,
+        "col17",
+        DataType.TIMESTAMP,
+        "col19",
+        DataType.TIME,
+        "col22",
+        DataType.BOOLEAN);
   }
 
   private TableMetadata prepareTableMetadataForOracle() {
@@ -395,6 +403,7 @@ private TableMetadata prepareTableMetadataForOracle() {
         .addColumn("col19", DataType.TIME)
         .addColumn("col20", DataType.TIMESTAMPTZ)
         .addColumn("col21", DataType.TIMESTAMPTZ)
+        .addColumn("col22", DataType.BOOLEAN)
         .addPartitionKey("pk1")
         .addPartitionKey("pk2")
         .build();
diff --git a/core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineOracle.java b/core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineOracle.java
index 8e69660f69..3be3cf82ce 100644
--- a/core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineOracle.java
+++ b/core/src/main/java/com/scalar/db/storage/jdbc/RdbEngineOracle.java
@@ -308,6 +308,9 @@ DataType getDataTypeForScalarDbInternal(
                   numericTypeDescription, columnDescription));
         }
         if (digits == 0) {
+          if (columnSize == 1 && overrideDataType == DataType.BOOLEAN) {
+            return DataType.BOOLEAN;
+          }
           logger.info(
               "Data type larger than that of underlying database is assigned: {} to BIGINT",
               numericTypeDescription);
diff --git a/core/src/test/java/com/scalar/db/storage/jdbc/RdbEngineTest.java b/core/src/test/java/com/scalar/db/storage/jdbc/RdbEngineTest.java
index ff839f29ac..1d7d14edfb 100644
--- a/core/src/test/java/com/scalar/db/storage/jdbc/RdbEngineTest.java
+++ b/core/src/test/java/com/scalar/db/storage/jdbc/RdbEngineTest.java
@@ -99,6 +99,9 @@ private static void prepareDataTypeMap() {
     DATA_TYPE_MAP.get(POSTGRESQL).put(new Column(JDBCType.BIT, "bool", 1, 0), DataType.BOOLEAN);
     DATA_TYPE_MAP.get(SQL_SERVER).put(new Column(JDBCType.BIT, "bit", 1, 0), DataType.BOOLEAN);
     DATA_TYPE_MAP.get(DB2).put(new Column(JDBCType.BOOLEAN, "BOOLEAN"), DataType.BOOLEAN);
+    DATA_TYPE_MAP
+        .get(ORACLE)
+        .put(new Column(JDBCType.NUMERIC, "NUMBER", 1, 0, DataType.BOOLEAN), DataType.BOOLEAN);
 
     // INT
     DATA_TYPE_MAP.get(MYSQL).put(new Column(JDBCType.TINYINT, "TINYINT"), DataType.INT);
@@ -203,6 +206,7 @@ private static void prepareDataTypeMap() {
     DATA_TYPE_MAP.get(ORACLE).put(new Column(JDBCType.NUMERIC, "NUMBER", 15, 0), DataType.BIGINT);
     DATA_TYPE_MAP.get(ORACLE).put(new Column(JDBCType.NUMERIC, "NUMBER", 15, 2), DataType.DOUBLE);
     DATA_TYPE_MAP.get(ORACLE).put(new Column(JDBCType.NUMERIC, "NUMBER", 16, 0), null);
+    DATA_TYPE_MAP.get(ORACLE).put(new Column(JDBCType.NUMERIC, "NUMBER", 1, 0), DataType.BIGINT);
     DATA_TYPE_MAP.get(SQL_SERVER).put(new Column(JDBCType.NUMERIC, "numeric"), null);
     DATA_TYPE_MAP.get(SQL_SERVER).put(new Column(JDBCType.DECIMAL, "decimal"), null);
     DATA_TYPE_MAP.get(DB2).put(new Column(JDBCType.DECIMAL, "DECIMAL"), null);