Merge pull request #489 from jeffgbutler/gh-488

Add Ability to Specify Table Aliases on DELETE and UPDATE Statements

Author: jeffgbutler

CHANGELOG.md

@@ -9,6 +9,9 @@ GitHub milestone: [https://github.com/mybatis/mybatis-dynamic-sql/issues?q=miles
 1. Added support for criteria groups without an initial criteria. This makes it possible to create an independent list
    of pre-created criteria and then add the list to a where clause. See the tests in the related pull request for
    usage examples. ([#462](https://github.com/mybatis/mybatis-dynamic-sql/pull/462))
+2. Added the ability to specify a table alias on DELETE and UPDATE statements.
+   This is especially useful when working with a sub-query with an exists or not exists condition.
+   ([#489](https://github.com/mybatis/mybatis-dynamic-sql/pull/489))
 
 ## Release 1.4.0 - March 3, 2022
 

src/main/java/org/mybatis/dynamic/sql/SqlBuilder.java

@@ -128,6 +128,10 @@ static DeleteDSL<DeleteModel> deleteFrom(SqlTable table) {
         return DeleteDSL.deleteFrom(table);
     }
 
+    static DeleteDSL<DeleteModel> deleteFrom(SqlTable table, String tableAlias) {
+        return DeleteDSL.deleteFrom(table, tableAlias);
+    }
+
     static <T> InsertDSL.IntoGatherer<T> insert(T row) {
         return InsertDSL.insert(row);
     }
@@ -210,6 +214,10 @@ static UpdateDSL<UpdateModel> update(SqlTable table) {
         return UpdateDSL.update(table);
     }
 
+    static UpdateDSL<UpdateModel> update(SqlTable table, String tableAlias) {
+        return UpdateDSL.update(table, tableAlias);
+    }
+
     static WhereDSL where() {
         return WhereDSL.where();
     }

src/main/java/org/mybatis/dynamic/sql/delete/DeleteDSL.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -29,10 +29,12 @@ public class DeleteDSL<R> extends AbstractWhereSupport<DeleteDSL<R>.DeleteWhereB
 
     private final Function<DeleteModel, R> adapterFunction;
     private final SqlTable table;
+    private final String tableAlias;
     private final DeleteWhereBuilder whereBuilder = new DeleteWhereBuilder();
 
-    private DeleteDSL(SqlTable table, Function<DeleteModel, R> adapterFunction) {
+    private DeleteDSL(SqlTable table, String tableAlias, Function<DeleteModel, R> adapterFunction) {
         this.table = Objects.requireNonNull(table);
+        this.tableAlias = tableAlias;
         this.adapterFunction = Objects.requireNonNull(adapterFunction);
     }
 
@@ -42,7 +44,7 @@ public DeleteWhereBuilder where() {
     }
 
     /**
-     * WARNING! Calling this method could result in an delete statement that deletes
+     * WARNING! Calling this method could result in a delete statement that deletes
      * all rows in a table.
      *
      * @return the model class
@@ -51,17 +53,22 @@ public DeleteWhereBuilder where() {
     @Override
     public R build() {
         DeleteModel deleteModel = DeleteModel.withTable(table)
+                .withTableAlias(tableAlias)
                 .withWhereModel(whereBuilder.buildWhereModel())
                 .build();
         return adapterFunction.apply(deleteModel);
     }
 
-    public static <R> DeleteDSL<R> deleteFrom(Function<DeleteModel, R> adapterFunction, SqlTable table) {
-        return new DeleteDSL<>(table, adapterFunction);
+    public static <R> DeleteDSL<R> deleteFrom(Function<DeleteModel, R> adapterFunction, SqlTable table, String tableAlias) {
+        return new DeleteDSL<>(table, tableAlias, adapterFunction);
     }
 
     public static DeleteDSL<DeleteModel> deleteFrom(SqlTable table) {
-        return deleteFrom(Function.identity(), table);
+        return deleteFrom(Function.identity(), table, null);
+    }
+
+    public static DeleteDSL<DeleteModel> deleteFrom(SqlTable table, String tableAlias) {
+        return deleteFrom(Function.identity(), table, tableAlias);
     }
 
     public class DeleteWhereBuilder extends AbstractWhereDSL<DeleteWhereBuilder> implements Buildable<R> {

src/main/java/org/mybatis/dynamic/sql/delete/DeleteModel.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -27,17 +27,23 @@
 
 public class DeleteModel {
     private final SqlTable table;
+    private final String tableAlias;
     private final WhereModel whereModel;
 
     private DeleteModel(Builder builder) {
         table = Objects.requireNonNull(builder.table);
         whereModel = builder.whereModel;
+        tableAlias = builder.tableAlias;
     }
 
     public SqlTable table() {
         return table;
     }
 
+    public Optional<String> tableAlias() {
+        return Optional.ofNullable(tableAlias);
+    }
+
     public Optional<WhereModel> whereModel() {
         return Optional.ofNullable(whereModel);
     }
@@ -56,13 +62,19 @@ public static Builder withTable(SqlTable table) {
 
     public static class Builder {
         private SqlTable table;
+        private String tableAlias;
         private WhereModel whereModel;
 
         public Builder withTable(SqlTable table) {
             this.table = table;
             return this;
         }
 
+        public Builder withTableAlias(String tableAlias) {
+            this.tableAlias = tableAlias;
+            return this;
+        }
+
         public Builder withWhereModel(WhereModel whereModel) {
             this.whereModel = whereModel;
             return this;

src/main/java/org/mybatis/dynamic/sql/delete/render/DeleteRenderer.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -21,7 +21,9 @@
 import java.util.Optional;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import org.mybatis.dynamic.sql.SqlTable;
 import org.mybatis.dynamic.sql.delete.DeleteModel;
+import org.mybatis.dynamic.sql.render.ExplicitTableAliasCalculator;
 import org.mybatis.dynamic.sql.render.RenderingStrategy;
 import org.mybatis.dynamic.sql.render.TableAliasCalculator;
 import org.mybatis.dynamic.sql.where.WhereModel;
@@ -31,10 +33,14 @@
 public class DeleteRenderer {
     private final DeleteModel deleteModel;
     private final RenderingStrategy renderingStrategy;
+    private final TableAliasCalculator tableAliasCalculator;
 
     private DeleteRenderer(Builder builder) {
         deleteModel = Objects.requireNonNull(builder.deleteModel);
         renderingStrategy = Objects.requireNonNull(builder.renderingStrategy);
+        tableAliasCalculator = builder.deleteModel.tableAlias()
+                .map(a -> ExplicitTableAliasCalculator.of(deleteModel.table(), a))
+                .orElseGet(TableAliasCalculator::empty);
     }
 
     public DeleteStatementProvider render() {
@@ -56,8 +62,12 @@ private String calculateDeleteStatement(WhereClauseProvider whereClause) {
     }
 
     private String calculateDeleteStatement() {
-        return "delete from" //$NON-NLS-1$
-                + spaceBefore(deleteModel.table().tableNameAtRuntime());
+        SqlTable table = deleteModel.table();
+        String tableName = table.tableNameAtRuntime();
+        String aliasedTableName = tableAliasCalculator.aliasForTable(table)
+                .map(a -> tableName + " " + a).orElse(tableName); //$NON-NLS-1$
+
+        return "delete from" + spaceBefore(aliasedTableName); //$NON-NLS-1$
     }
 
     private DeleteStatementProvider renderWithoutWhereClause() {
@@ -69,7 +79,7 @@ private Optional<WhereClauseProvider> renderWhereClause(WhereModel whereModel) {
         return WhereRenderer.withWhereModel(whereModel)
                 .withRenderingStrategy(renderingStrategy)
                 .withSequence(new AtomicInteger(1))
-                .withTableAliasCalculator(TableAliasCalculator.empty())
+                .withTableAliasCalculator(tableAliasCalculator)
                 .build()
                 .render();
     }

src/main/java/org/mybatis/dynamic/sql/render/TableAliasCalculator.java

@@ -29,12 +29,12 @@ static TableAliasCalculator empty() {
         return new TableAliasCalculator() {
             @Override
             public Optional<String> aliasForColumn(SqlTable table) {
-                return Optional.empty();
+                return table.tableAlias();
             }
 
             @Override
             public Optional<String> aliasForTable(SqlTable table) {
-                return Optional.empty();
+                return table.tableAlias();
             }
         };
     }

src/main/java/org/mybatis/dynamic/sql/update/UpdateDSL.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2021 the original author or authors.
+ *    Copyright 2016-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -45,10 +45,12 @@ public class UpdateDSL<R> extends AbstractWhereSupport<UpdateDSL<R>.UpdateWhereB
     private final Function<UpdateModel, R> adapterFunction;
     private final List<AbstractColumnMapping> columnMappings = new ArrayList<>();
     private final SqlTable table;
+    private final String tableAlias;
     private final UpdateWhereBuilder whereBuilder = new UpdateWhereBuilder();
 
-    private UpdateDSL(SqlTable table, Function<UpdateModel, R> adapterFunction) {
+    private UpdateDSL(SqlTable table, String tableAlias, Function<UpdateModel, R> adapterFunction) {
         this.table = Objects.requireNonNull(table);
+        this.tableAlias = tableAlias;
         this.adapterFunction = Objects.requireNonNull(adapterFunction);
     }
 
@@ -71,18 +73,23 @@ public UpdateWhereBuilder where() {
     @Override
     public R build() {
         UpdateModel updateModel = UpdateModel.withTable(table)
+                .withTableAlias(tableAlias)
                 .withColumnMappings(columnMappings)
                 .withWhereModel(whereBuilder.buildWhereModel())
                 .build();
         return adapterFunction.apply(updateModel);
     }
 
-    public static <R> UpdateDSL<R> update(Function<UpdateModel, R> adapterFunction, SqlTable table) {
-        return new UpdateDSL<>(table, adapterFunction);
+    public static <R> UpdateDSL<R> update(Function<UpdateModel, R> adapterFunction, SqlTable table, String tableAlias) {
+        return new UpdateDSL<>(table, tableAlias, adapterFunction);
     }
 
     public static UpdateDSL<UpdateModel> update(SqlTable table) {
-        return update(Function.identity(), table);
+        return update(Function.identity(), table, null);
+    }
+
+    public static UpdateDSL<UpdateModel> update(SqlTable table, String tableAlias) {
+        return update(Function.identity(), table, tableAlias);
     }
 
     public class SetClauseFinisher<T> {

src/main/java/org/mybatis/dynamic/sql/update/UpdateModel.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -32,19 +32,25 @@
 
 public class UpdateModel {
     private final SqlTable table;
+    private final String tableAlias;
     private final WhereModel whereModel;
     private final List<AbstractColumnMapping> columnMappings;
 
     private UpdateModel(Builder builder) {
         table = Objects.requireNonNull(builder.table);
         whereModel = builder.whereModel;
         columnMappings = Objects.requireNonNull(builder.columnMappings);
+        tableAlias = builder.tableAlias;
     }
 
     public SqlTable table() {
         return table;
     }
 
+    public Optional<String> tableAlias() {
+        return Optional.ofNullable(tableAlias);
+    }
+
     public Optional<WhereModel> whereModel() {
         return Optional.ofNullable(whereModel);
     }
@@ -67,6 +73,7 @@ public static Builder withTable(SqlTable table) {
 
     public static class Builder {
         private SqlTable table;
+        private String tableAlias;
         private WhereModel whereModel;
         private final List<AbstractColumnMapping> columnMappings = new ArrayList<>();
 
@@ -75,6 +82,11 @@ public Builder withTable(SqlTable table) {
             return this;
         }
 
+        public Builder withTableAlias(String tableAlias) {
+            this.tableAlias = tableAlias;
+            return this;
+        }
+
         public Builder withColumnMappings(List<AbstractColumnMapping> columnMappings) {
             this.columnMappings.addAll(columnMappings);
             return this;