README.md in embulk-output-oracle-0.5.1 vs README.md in embulk-output-oracle-0.6.0

@@ -23,11 +23,11 @@
 - **insert_method**: see below
 - **batch_size**: size of a single batch insert (integer, default: 16777216)
 - **default_timezone**: If input column type (embulk type) is timestamp, this plugin needs to format the timestamp into a SQL string. This default_timezone option is used to control the timezone. You can overwrite timezone for each columns using column_options option. (string, default: `UTC`)
 - **column_options**: advanced: a key-value pairs where key is a column name and value is options for the column.
   - **type**: type of a column when this plugin creates new tables (e.g. `VARCHAR(255)`, `INTEGER NOT NULL UNIQUE`). This used when this plugin creates intermediate tables (insert, truncate_insert and merge modes), when it creates the target table (insert_direct and replace modes), and when it creates nonexistent target table automatically. (string, default: depends on input column type. `BIGINT` if input column type is long, `BOOLEAN` if boolean, `DOUBLE PRECISION` if double, `CLOB` if string, `TIMESTAMP` if timestamp)
-  - **value_type**: This plugin converts input column type (embulk type) into a database type to build a INSERT statement. This value_type option controls the type of the value in a INSERT statement. (string, default: depends on input column type. Available values options are: `byte`, `short`, `int`, `long`, `double`, `float`, `boolean`, `string`, `nstring`, `date`, `time`, `timestamp`, `decimal`, `null`, `pass`)
+  - **value_type**: This plugin converts input column type (embulk type) into a database type to build a INSERT statement. This value_type option controls the type of the value in a INSERT statement. (string, default: depends on the sql type of the column. Available values options are: `byte`, `short`, `int`, `long`, `double`, `float`, `boolean`, `string`, `nstring`, `date`, `time`, `timestamp`, `decimal`, `json`, `null`, `pass`)
   - **timestamp_format**: If input column type (embulk type) is timestamp and value_type is `string` or `nstring`, this plugin needs to format the timestamp value into a string. This timestamp_format option is used to control the format of the timestamp. (string, default: `%Y-%m-%d %H:%M:%S.%6N`)
   - **timezone**: If input column type (embulk type) is timestamp, this plugin needs to format the timestamp value into a SQL string. In this cases, this timezone option is used to control the timezone. (string, value of default_timezone option is used by default)
 
 ### Modes
 
@@ -58,9 +58,26 @@
 It requires Oracle JDBC driver too, but the version 12 driver doesn't work (the version 11 driver works).
 
 "oci" means direct path insert using OCI(Oracle Call Interface). It is fastest.
 It requires both Oracle JDBC driver and Oracle Instant Client (version 12.1.0.2.0).
 You must set the library loading path to the OCI library.
+
+### Supported types
+
+|database type|default value_type|note|
+|:--|:--|:--|
+|NUMBER|decimal||
+|FLOAT|double||
+|CHAR|string||
+|VARCHAR2|string||
+|CLOB|string||
+|NCHAR|nstring||
+|NVARCHAR2|nstring||
+|NCLOB|nstring||
+|DATE|timestamp|Oracle DATE type stores date and time information.|
+|TIMESTAMP|timestamp||
+
+You can use other types by specifying `value_type` in `column_options`.
 
 ### Example
 
 ```yaml
 out: