[Improvement] information_schema.columns support COLUMN KEY (#11228)

fe/fe-core/src/main/java/org/apache/doris/catalog/KeysType.java

@@ -19,12 +19,18 @@ package org.apache.doris.catalog;
 
 import org.apache.doris.thrift.TKeysType;
 
+/**
+ * Olap Table key type.
+ **/
 public enum KeysType {
     PRIMARY_KEYS,
     DUP_KEYS,
     UNIQUE_KEYS,
     AGG_KEYS;
 
+    /**
+     * Determine whether it is an aggregation type.
+     **/
     public boolean isAggregationFamily() {
         switch (this) {
             case AGG_KEYS:
@@ -35,6 +41,9 @@ public enum KeysType {
         }
     }
 
+    /**
+     * Type convert to thrift.
+     **/
     public TKeysType toThrift() {
         switch (this) {
             case PRIMARY_KEYS:
@@ -50,6 +59,9 @@ public enum KeysType {
         }
     }
 
+    /**
+     * Type convert from thrift
+     **/
     public static KeysType fromThrift(TKeysType tKeysType) {
         switch (tKeysType) {
             case PRIMARY_KEYS:
@@ -65,6 +77,9 @@ public enum KeysType {
         }
     }
 
+    /**
+     * Type convert to sql.
+     **/
     public String toSql() {
         switch (this) {
             case PRIMARY_KEYS:
@@ -79,4 +94,22 @@ public enum KeysType {
                 return null;
         }
     }
+
+    /**
+     * Type convert to information_schema, try to be compatible with mysql.
+     **/
+    public String toMetadata() {
+        switch (this) {
+            case PRIMARY_KEYS:
+                return "PRI";
+            case DUP_KEYS:
+                return "DUP";
+            case UNIQUE_KEYS:
+                return "UNI";
+            case AGG_KEYS:
+                return "AGG";
+            default:
+                return "";
+        }
+    }
 }

fe/fe-core/src/main/java/org/apache/doris/service/FrontendServiceImpl.java

@@ -427,6 +427,11 @@ public class FrontendServiceImpl implements FrontendService.Iface {
                         if (comment != null) {
                             colDef.setComment(comment);
                         }
+                        if (column.isKey()) {
+                            if (table instanceof OlapTable) {
+                                desc.setColumnKey(((OlapTable) table).getKeysType().toMetadata());
+                            }
+                        }
                         columns.add(colDef);
                     }
                 } finally {