Merge pull request #20 from EzFramework/feature/delete-from

Dialect-aware DELETE-query rendering & DELETE LIMIT support

Author: ez-plugins

.github/workflows/code-quality.yml

@@ -52,11 +52,8 @@ jobs:
         with:
           name: jacoco-report
           path: target/site/jacoco/
-      - name: Comment JaCoCo coverage summary in PR
-        if: github.event_name == 'pull_request'
-        uses: madrapps/jacoco-report@v1.7.2
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v5
         with:
-          paths: target/site/jacoco/jacoco.xml
-          token: ${{ secrets.GITHUB_TOKEN }}
-          min-coverage-overall: 0
-          min-coverage-changed-files: 0
+          files: target/site/jacoco/jacoco.xml
+          token: ${{ secrets.CODECOV_TOKEN }}

README.md

@@ -20,7 +20,7 @@ Add the dependency to your `pom.xml`:
 <dependency>
     <groupId>com.github.EzFramework</groupId>
     <artifactId>JavaQueryBuilder</artifactId>
-    <version>1.0.3</version>
+    <version>1.0.4</version>
 </dependency>
 ```
 
@@ -321,14 +321,39 @@ SqlResult result = new QueryBuilder()
 // → SELECT * FROM "users" WHERE "status" = ?
 ```
 
-| Dialect | Identifier quoting | Boolean values |
-|---|---|---|
-| `SqlDialect.STANDARD` | none | `true` / `false` |
-| `SqlDialect.MYSQL` | back-ticks `` `col` `` | `true` / `false` |
-| `SqlDialect.SQLITE` | double quotes `"col"` | `1` / `0` |
+| Dialect | Identifier quoting | Boolean values | DELETE LIMIT |
+|---|---|---|---|
+| `SqlDialect.STANDARD` | none | `true` / `false` | no |
+| `SqlDialect.MYSQL` | back-ticks `` `col` `` | `true` / `false` | yes |
+| `SqlDialect.SQLITE` | double quotes `"col"` | `1` / `0` | yes |
 
 MySQL back-tick quoting safely handles reserved words and case-sensitive identifiers. SQLite double-quote quoting serves the same purpose, and Java booleans are converted to `1`/`0` to match SQLite's integer-backed boolean storage.
 
+### Dialect-aware DELETE rendering
+
+Every `SqlDialect` exposes a `renderDelete(Query query)` method that generates a fully dialect-aware `DELETE FROM ... WHERE ...` statement, identifier quoting and all. MySQL and SQLite also append a `LIMIT` clause when one is set on the query; the standard dialect silently ignores it.
+
+```java
+// Obtain a Query from any QueryBuilder call
+Query query = new QueryBuilder()
+    .from("users")
+    .whereEquals("id", 42)
+    .limit(1)
+    .build();
+
+// Standard — no quoting, no LIMIT
+SqlDialect.STANDARD.renderDelete(query);
+// → DELETE FROM users WHERE id = ?   params=[42]
+
+// MySQL — back-tick quoting + LIMIT
+SqlDialect.MYSQL.renderDelete(query);
+// → DELETE FROM `users` WHERE `id` = ? LIMIT 1   params=[42]
+
+// SQLite — double-quote quoting + LIMIT
+SqlDialect.SQLITE.renderDelete(query);
+// → DELETE FROM "users" WHERE "id" = ? LIMIT 1   params=[42]
+```
+
 ## How SQL Generation Works
 
 `buildSql(table)` (or `query.toSql(table)`) translates the `Query` into a single-line parameterized SQL string. All values are returned separately as a `List<Object>` — the SQL string itself only contains `?` placeholders, so **user-supplied values are never interpolated into the string**. This makes it inherently safe against SQL injection when used with a `PreparedStatement`.

pom.xml

@@ -5,7 +5,7 @@
 
     <groupId>com.github.EzFramework</groupId>
     <artifactId>java-query-builder</artifactId>
-    <version>1.0.3</version>
+    <version>1.0.4</version>
     <packaging>jar</packaging>
 
     <name>JavaQueryBuilder</name>

src/main/java/com/github/ezframework/javaquerybuilder/query/sql/AbstractSqlDialect.java

@@ -11,10 +11,13 @@
 import com.github.ezframework.javaquerybuilder.query.condition.Operator;
 
 /**
- * Base SQL rendering logic for SELECT queries.
+ * Base SQL rendering logic for SELECT and DELETE queries.
  *
- * <p>Implements the standard (ANSI) SQL dialect. Subclasses may override
- * {@link #quoteIdentifier(String)} to apply dialect-specific identifier quoting.
+ * <p>Implements the standard (ANSI) SQL dialect and provides shared helpers for
+ * rendering {@code WHERE} clauses. Subclasses may override
+ * {@link #quoteIdentifier(String)} to apply dialect-specific identifier quoting
+ * and {@link #supportsDeleteLimit()} to enable dialect-specific DELETE
+ * {@code LIMIT} behaviour.
  *
  * @author EzFramework
  * @version 1.0.0
@@ -44,6 +47,44 @@ protected String quoteIdentifier(String name) {
         return name;
     }
 
+    @Override
+    public SqlResult renderDelete(Query query) {
+        final StringBuilder sql = new StringBuilder();
+        final List<Object> params = new ArrayList<>();
+        sql.append("DELETE FROM ").append(quoteIdentifier(query.getTable()));
+        appendWhereClause(sql, params, query);
+
+        if (supportsDeleteLimit() && query.getLimit() != null && query.getLimit() >= 0) {
+            sql.append(" LIMIT ").append(query.getLimit());
+        }
+
+        final String sqlStr = sql.toString();
+        final List<Object> paramsCopy = Collections.unmodifiableList(new ArrayList<>(params));
+        return new SqlResult() {
+            @Override
+            public String getSql() {
+                return sqlStr;
+            }
+
+            @Override
+            public List<Object> getParameters() {
+                return paramsCopy;
+            }
+        };
+    }
+
+    /**
+     * Hook for dialects that support a `LIMIT` clause on DELETE statements
+     * (for example, MySQL). The default implementation returns {@code false},
+     * meaning the base renderer will ignore `limit` on `Query` for DELETE.
+     * Subclasses that want to enable `LIMIT` should override this method.
+     *
+     * @return {@code true} if the dialect appends a `LIMIT` to DELETE statements
+     */
+    protected boolean supportsDeleteLimit() {
+        return false;
+    }
+
     @Override
     public SqlResult render(Query query) {
         final StringBuilder sql = new StringBuilder();
@@ -94,7 +135,7 @@ private void appendSelectColumns(StringBuilder sql, Query query) {
         }
     }
 
-    private void appendWhereClause(StringBuilder sql, List<Object> params, Query query) {
+    protected void appendWhereClause(StringBuilder sql, List<Object> params, Query query) {
         final List<ConditionEntry> conditions = query.getConditions();
         if (conditions.isEmpty()) {
             return;
@@ -111,7 +152,7 @@ private void appendWhereClause(StringBuilder sql, List<Object> params, Query que
     }
 
     @SuppressWarnings("unchecked")
-    private void appendConditionFragment(StringBuilder sql, List<Object> params, ConditionEntry entry) {
+    protected void appendConditionFragment(StringBuilder sql, List<Object> params, ConditionEntry entry) {
         final Operator op = entry.getCondition().getOperator();
         if (COMPARISON_OPERATORS.containsKey(op)) {
             sql.append(COMPARISON_OPERATORS.get(op));

src/main/java/com/github/ezframework/javaquerybuilder/query/sql/SqlDialect.java

@@ -33,4 +33,17 @@ public interface SqlDialect {
      * @return the SQL result containing the SQL string and bound parameters
      */
     SqlResult render(Query query);
+
+    /**
+     * Renders a DELETE statement for the given query (DELETE FROM ... WHERE ...).
+     *
+     * @param query the query describing the delete target and conditions
+        * @return the SQL result containing the SQL string and bound parameters
+        *
+        * <p>Default behaviour is implemented by {@link AbstractSqlDialect#renderDelete(Query)},
+        * which renders {@code DELETE FROM <table> WHERE ...} and preserves parameter
+        * ordering to match {@link #render(Query)}. Dialects that support a DELETE
+        * {@code LIMIT} may enable it by overriding {@link AbstractSqlDialect#supportsDeleteLimit()}.
+     */
+    SqlResult renderDelete(Query query);
 }

src/main/java/com/github/ezframework/javaquerybuilder/query/sql/mysql/MySqlDialect.java

@@ -17,4 +17,9 @@ public class MySqlDialect extends AbstractSqlDialect {
     protected String quoteIdentifier(String name) {
         return "`" + name + "`";
     }
+
+    @Override
+    protected boolean supportsDeleteLimit() {
+        return true;
+    }
 }

src/main/java/com/github/ezframework/javaquerybuilder/query/sql/sqlite/SqliteDialect.java

@@ -17,4 +17,9 @@ public class SqliteDialect extends AbstractSqlDialect {
     protected String quoteIdentifier(String name) {
         return "\"" + name + "\"";
     }
+
+    @Override
+    protected boolean supportsDeleteLimit() {
+        return true;
+    }
 }

src/test/java/com/github/ezframework/javaquerybuilder/query/sql/AbstractSqlDialectDeleteTest.java

@@ -0,0 +1,89 @@
+package com.github.ezframework.javaquerybuilder.query.sql;
+
+import java.util.List;
+
+import com.github.ezframework.javaquerybuilder.query.builder.QueryBuilder;
+import com.github.ezframework.javaquerybuilder.query.Query;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class AbstractSqlDialectDeleteTest {
+
+    static class DummyDialect extends AbstractSqlDialect {}
+
+    @Test
+    void deleteParametersMatchSelectParameters() {
+        final DummyDialect dialect = new DummyDialect();
+        final com.github.ezframework.javaquerybuilder.query.condition.ConditionEntry ae =
+            new com.github.ezframework.javaquerybuilder.query.condition.ConditionEntry("a",
+                new com.github.ezframework.javaquerybuilder.query.condition.Condition(
+                    com.github.ezframework.javaquerybuilder.query.condition.Operator.EQ, 1),
+                com.github.ezframework.javaquerybuilder.query.condition.Connector.AND);
+
+        final com.github.ezframework.javaquerybuilder.query.condition.ConditionEntry ce =
+            new com.github.ezframework.javaquerybuilder.query.condition.ConditionEntry("c",
+                new com.github.ezframework.javaquerybuilder.query.condition.Condition(
+                    com.github.ezframework.javaquerybuilder.query.condition.Operator.GT, 2),
+                com.github.ezframework.javaquerybuilder.query.condition.Connector.AND);
+
+        final com.github.ezframework.javaquerybuilder.query.condition.ConditionEntry inE =
+            new com.github.ezframework.javaquerybuilder.query.condition.ConditionEntry("l",
+                new com.github.ezframework.javaquerybuilder.query.condition.Condition(
+                    com.github.ezframework.javaquerybuilder.query.condition.Operator.IN, List.of(6, 7)),
+                com.github.ezframework.javaquerybuilder.query.condition.Connector.AND);
+
+        final com.github.ezframework.javaquerybuilder.query.condition.ConditionEntry betweenE =
+            new com.github.ezframework.javaquerybuilder.query.condition.ConditionEntry("n",
+                new com.github.ezframework.javaquerybuilder.query.condition.Condition(
+                    com.github.ezframework.javaquerybuilder.query.condition.Operator.BETWEEN, List.of(10, 11)),
+                com.github.ezframework.javaquerybuilder.query.condition.Connector.AND);
+
+        final Query q = new Query();
+        q.setTable("t");
+        q.setConditions(List.of(ae, ce, inE, betweenE));
+
+        final SqlResult select = dialect.render(q);
+        final SqlResult del = dialect.renderDelete(q);
+
+        assertTrue(del.getSql().startsWith("DELETE FROM t"));
+        assertTrue(del.getSql().contains("WHERE"));
+        assertTrue(del.getSql().contains("?"));
+        assertEquals(select.getParameters(), del.getParameters());
+    }
+
+    @Test
+    void sqliteAndMysqlApplyQuotingAndLimitBehavior() {
+        final QueryBuilder qb = new QueryBuilder().from("users").whereEquals("id", 42).limit(5);
+        final Query q = qb.build();
+        q.setTable("users");
+        final com.github.ezframework.javaquerybuilder.query.sql.mysql.MySqlDialect my =
+            new com.github.ezframework.javaquerybuilder.query.sql.mysql.MySqlDialect();
+        final SqlResult myDel = my.renderDelete(q);
+        assertTrue(myDel.getSql().startsWith("DELETE FROM `users`"));
+        assertTrue(myDel.getSql().contains("LIMIT 5"));
+
+        final SqlDialect sqlite = new com.github.ezframework.javaquerybuilder.query.sql.sqlite.SqliteDialect();
+        final SqlResult sqDel = sqlite.renderDelete(q);
+        assertTrue(sqDel.getSql().startsWith("DELETE FROM \"users\""));
+        assertTrue(sqDel.getSql().contains("LIMIT 5"));
+
+        final DummyDialect d = new DummyDialect();
+        final SqlResult dDel = d.renderDelete(q);
+        assertTrue(dDel.getSql().startsWith("DELETE FROM users"));
+        assertFalse(dDel.getSql().contains("LIMIT"));
+    }
+
+    @Test
+    void inClauseGeneratesCorrectPlaceholderCountAndOrdering() {
+        final DummyDialect dialect = new DummyDialect();
+        final QueryBuilder qb = new QueryBuilder().from("items").whereIn("id", List.of(1, 2, 3));
+        final Query q = qb.build();
+        q.setTable("items");
+
+        final SqlResult del = dialect.renderDelete(q);
+        assertEquals("DELETE FROM items WHERE id IN (?, ?, ?)", del.getSql());
+        assertEquals(List.of(1, 2, 3), del.getParameters());
+    }
+}