docs: add python write demo (#60)

* chore: reteTimeOut => rateTimeOut

* doc effect: add python write vertex and edge code demo

* docs: delete duplicated code

* docs: move the section of demo

* docs: typo updated

Co-authored-by: Anqi <anqi.wang@vesoft.com>

README.md

@@ -176,7 +176,7 @@ only showing top 2 rows
 ### Write in PySpark
 
 Let's try a write example, by default, the `writeMode` is `insert`
-
+#### write vertex
 ```python
 df.write.format("com.vesoft.nebula.connector.NebulaDataSource").option(
     "type", "vertex").option(
@@ -190,7 +190,7 @@ df.write.format("com.vesoft.nebula.connector.NebulaDataSource").option(
     "passwd", "nebula").option(
     "user", "root").save()
 ```
-
+#### delete vertex
 For delete or update write mode, we could(for instance)specify with `writeMode` as `delete` like:
 ```python
 df.write.format("com.vesoft.nebula.connector.NebulaDataSource").option(
@@ -206,6 +206,44 @@ df.write.format("com.vesoft.nebula.connector.NebulaDataSource").option(
     "writeMode", "delete").option(
     "user", "root").save()
 ```
+#### write edge
+```python
+df.write.format("com.vesoft.nebula.connector.NebulaDataSource")\
+    .mode("overwrite")\
+    .option("srcPolicy", "")\
+    .option("dstPolicy", "")\
+    .option("metaAddress", "metad0:9559")\
+    .option("graphAddress", "graphd:9669")\
+    .option("user", "root")\
+    .option("passwd", "nebula")\
+    .option("type", "edge")\
+    .option("spaceName", "basketballplayer")\
+    .option("label", "server")\
+    .option("srcVertexField", "srcid")\
+    .option("dstVertexField", "dstid")\
+    .option("randkField", "")\
+    .option("batch", 100)\
+    .option("writeMode", "insert").save()   # delete to delete edge, update to update edge
+```
+#### delete edge
+```python
+df.write.format("com.vesoft.nebula.connector.NebulaDataSource")\
+    .mode("overwrite")\
+    .option("srcPolicy", "")\
+    .option("dstPolicy", "")\
+    .option("metaAddress", "metad0:9559")\
+    .option("graphAddress", "graphd:9669")\
+    .option("user", "root")\
+    .option("passwd", "nebula")\
+    .option("type", "edge")\
+    .option("spaceName", "basketballplayer")\
+    .option("label", "server")\
+    .option("srcVertexField", "srcid")\
+    .option("dstVertexField", "dstid")\
+    .option("randkField", "")\
+    .option("batch", 100)\
+    .option("writeMode", "delete").save()   # delete to delete edge, update to update edge
+```
 
 ### Options in PySpark
 
@@ -221,7 +259,7 @@ For more options, i.e. delete edge with vertex being deleted, refer to [nebula/c
   val VERTEX_FIELD         = "vertexField"
   val SRC_VERTEX_FIELD     = "srcVertexField"
   val DST_VERTEX_FIELD     = "dstVertexField"
-  val RANK_FIELD           = "rankField"
+  val RANK_FIELD           = "randkField"
   val BATCH: String        = "batch"
   val VID_AS_PROP: String  = "vidAsProp"
   val SRC_AS_PROP: String  = "srcAsProp"
@@ -251,6 +289,7 @@ spark = SparkSession.builder.config(
     "/path_to/nebula-spark-connector-3.0.0.jar").appName(
         "nebula-connector").getOrCreate()
 
+# read vertex
 df = spark.read.format(
   "com.vesoft.nebula.connector.NebulaDataSource").option(
     "type", "vertex").option(

README_CN.md

@@ -176,7 +176,7 @@ only showing top 2 rows
 ### PySpark 中写 NebulaGraph 中数据
 
 再试一试写入数据的例子，默认不指定的情况下 `writeMode` 是 `insert`：
-
+#### 写入点
 ```python
 df.write.format("com.vesoft.nebula.connector.NebulaDataSource").option(
     "type", "vertex").option(
@@ -190,6 +190,7 @@ df.write.format("com.vesoft.nebula.connector.NebulaDataSource").option(
     "passwd", "nebula").option(
     "user", "root").save()
 ```
+#### 删除点
 如果想指定 `delete` 或者 `update` 的非默认写入模式，增加 `writeMode` 的配置，比如 `delete` 的例子：
 
 ```python
@@ -206,6 +207,44 @@ df.write.format("com.vesoft.nebula.connector.NebulaDataSource").option(
     "writeMode", "delete").option(
     "user", "root").save()
 ```
+#### 写入边
+```python
+df.write.format("com.vesoft.nebula.connector.NebulaDataSource")\
+    .mode("overwrite")\
+    .option("srcPolicy", "")\
+    .option("dstPolicy", "")\
+    .option("metaAddress", "metad0:9559")\
+    .option("graphAddress", "graphd:9669")\
+    .option("user", "root")\
+    .option("passwd", "nebula")\
+    .option("type", "edge")\
+    .option("spaceName", "basketballplayer")\
+    .option("label", "server")\
+    .option("srcVertexField", "srcid")\
+    .option("dstVertexField", "dstid")\
+    .option("rankField", "")\
+    .option("batch", 100)\
+    .option("writeMode", "insert").save()   # delete to delete edge, update to update edge
+```
+#### 删除边
+```python
+df.write.format("com.vesoft.nebula.connector.NebulaDataSource")\
+    .mode("overwrite")\
+    .option("srcPolicy", "")\
+    .option("dstPolicy", "")\
+    .option("metaAddress", "metad0:9559")\
+    .option("graphAddress", "graphd:9669")\
+    .option("user", "root")\
+    .option("passwd", "nebula")\
+    .option("type", "edge")\
+    .option("spaceName", "basketballplayer")\
+    .option("label", "server")\
+    .option("srcVertexField", "srcid")\
+    .option("dstVertexField", "dstid")\
+    .option("randkField", "")\
+    .option("batch", 100)\
+    .option("writeMode", "delete").save()   # delete to delete edge, update to update edge
+```
 
 ### 关于 PySpark 读写的 option
 
@@ -222,7 +261,7 @@ df.write.format("com.vesoft.nebula.connector.NebulaDataSource").option(
   val VERTEX_FIELD         = "vertexField"
   val SRC_VERTEX_FIELD     = "srcVertexField"
   val DST_VERTEX_FIELD     = "dstVertexField"
-  val RANK_FIELD           = "rankFiled"
+  val RANK_FIELD           = "randkField"
   val BATCH: String        = "batch"
   val VID_AS_PROP: String  = "vidAsProp"
   val SRC_AS_PROP: String  = "srcAsProp"
@@ -252,6 +291,7 @@ spark = SparkSession.builder.config(
     "/path_to/nebula-spark-connector-3.0.0.jar").appName(
         "nebula-connector").getOrCreate()
 
+# read vertex
 df = spark.read.format(
   "com.vesoft.nebula.connector.NebulaDataSource").option(
     "type", "vertex").option(

nebula-spark-connector/src/main/scala/com/vesoft/nebula/connector/NebulaOptions.scala

@@ -220,7 +220,7 @@ object NebulaOptions {
   val TIMEOUT: String            = "timeout"
   val CONNECTION_RETRY: String   = "connectionRetry"
   val EXECUTION_RETRY: String    = "executionRetry"
-  val RATE_TIME_OUT: String      = "reteTimeOut"
+  val RATE_TIME_OUT: String      = "rateTimeOut"
   val USER_NAME: String          = "user"
   val PASSWD: String             = "passwd"
   val ENABLE_GRAPH_SSL: String   = "enableGraphSSL"