imay commented on a change in pull request #1453: Fix bug that user can set
null default value to non-nullable column in create table stmt
URL: https://github.com/apache/incubator-doris/pull/1453#discussion_r302088419
##########
File path: fe/src/main/java/org/apache/doris/analysis/ColumnDef.java
##########
@@ -38,27 +38,58 @@
// pv bigint sum NULL DEFAULT "-1" "page visit"
public class ColumnDef {
private static final Logger LOG = LogManager.getLogger(ColumnDef.class);
- private static final String HLL_EMPTY_SET = "0";
+
+ /*
+ * User can set default value for a column
+ * eg:
+ * k1 INT NOT NULL DEFAULT "10"
+ * k1 INT NULL
+ * k1 INT NULL DEFAULT NULL
+ *
+ * ColumnnDef will be transformed to Column in Analysis phase, and in
Column, default value is a String.
+ * No matter does the user set the default value as NULL explicitly, or
not set default value,
+ * the default value in Column will be "null", so that Doris can not
distinguish between "not set" and "set as null".
+ *
+ * But this is OK because Column has another attribute "isAllowNull".
+ * If the column is not allowed to be null, and user does not set the
default value,
+ * even if default value saved in Column is null, the "null" value can not
be loaded into this column,
+ * so data correctness can be guaranteed.
+ */
+ public static class DefaultValue {
+ public boolean isSet;
+ public String value;
+
+ public DefaultValue(boolean isSet, String value) {
+ this.isSet = isSet;
+ this.value = value;
+ }
+
+ // no default value
+ public static DefaultValue NOT_SET = new DefaultValue(false, null);
+ // default null
+ public static DefaultValue NULL_DEFAULT_VALUE = new DefaultValue(true,
null);
+ // default "valuie"
Review comment:
```suggestion
// default "value"
```
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