Rewrote foreign key drop code in Patch

Plan/common/src/main/java/com/djrapitops/plan/system/database/databases/sql/objects/ForeignKeyConstraint.java

@@ -0,0 +1,71 @@
+/*
+ *  This file is part of Player Analytics (Plan).
+ *
+ *  Plan is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License v3 as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Plan is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with Plan. If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.djrapitops.plan.system.database.databases.sql.objects;
+
+/**
+ * Represents a FOREIGN KEY constraint in a MySQL database.
+ *
+ * @author Rsl1122
+ */
+public class ForeignKeyConstraint {
+
+    private final String table;
+    private final String referencedTable;
+    private final String column;
+    private final String refrencedColumn;
+    private final String constraintName;
+
+    public ForeignKeyConstraint(
+            String table, String referencedTable,
+            String column, String refrencedColumn,
+            String constraintName
+    ) {
+        this.table = table;
+        this.referencedTable = referencedTable;
+        this.column = column;
+        this.refrencedColumn = refrencedColumn;
+        this.constraintName = constraintName;
+    }
+
+    public String getTable() {
+        return table;
+    }
+
+    public String getReferencedTable() {
+        return referencedTable;
+    }
+
+    public String getColumn() {
+        return column;
+    }
+
+    public String getRefrencedColumn() {
+        return refrencedColumn;
+    }
+
+    public String getConstraintName() {
+        return constraintName;
+    }
+
+    @Override
+    public String toString() {
+        return "FK '" + constraintName + "' " +
+                table + "." + column +
+                " references " +
+                referencedTable + "." + refrencedColumn;
+    }
+}

Plan/common/src/main/java/com/djrapitops/plan/system/database/databases/sql/operation/Queries.java

@@ -0,0 +1,73 @@
+/*
+ *  This file is part of Player Analytics (Plan).
+ *
+ *  Plan is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License v3 as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Plan is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with Plan. If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.djrapitops.plan.system.database.databases.sql.operation;
+
+import com.djrapitops.plan.system.database.databases.sql.objects.ForeignKeyConstraint;
+import com.djrapitops.plan.system.database.databases.sql.processing.QueryStatement;
+
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Class that contains different SELECT statements.
+ *
+ * @author Rsl1122
+ */
+public class Queries {
+
+    private Queries() {
+        /* Static method class */
+    }
+
+    public static QueryStatement<List<ForeignKeyConstraint>> foreignKeyConstraintsOf(String tableSchema, String referencedTable) {
+        String keySQL = "SELECT TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME,REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE" +
+                " WHERE REFERENCED_TABLE_SCHEMA = ?" +
+                " AND REFERENCED_TABLE_NAME = ?";
+        return new QueryStatement<List<ForeignKeyConstraint>>(keySQL) {
+            @Override
+            public void prepare(PreparedStatement statement) throws SQLException {
+                statement.setString(1, tableSchema);
+                statement.setString(2, referencedTable);
+            }
+
+            @Override
+            public List<ForeignKeyConstraint> processResults(ResultSet set) throws SQLException {
+                List<ForeignKeyConstraint> constraints = new ArrayList<>();
+
+                while (set.next()) {
+                    String table = set.getString("TABLE_NAME");
+                    String referencedTable = set.getString("REFERENCED_TABLE_NAME");
+                    String column = set.getString("COLUMN_NAME");
+                    String referencedColumn = set.getString("REFERENCED_COLUMN");
+                    String constraintName = set.getString("CONSTRAINT_NAME");
+
+                    constraints.add(new ForeignKeyConstraint(
+                            table, referencedTable,
+                            column, referencedColumn,
+                            constraintName
+                    ));
+                }
+
+                return constraints;
+            }
+        };
+    }
+
+}

Plan/common/src/main/java/com/djrapitops/plan/system/database/databases/sql/patches/Patch.java

@@ -19,6 +19,8 @@ package com.djrapitops.plan.system.database.databases.sql.patches;
 import com.djrapitops.plan.api.exceptions.database.DBOpException;
 import com.djrapitops.plan.system.database.databases.DBType;
 import com.djrapitops.plan.system.database.databases.sql.SQLDB;
+import com.djrapitops.plan.system.database.databases.sql.objects.ForeignKeyConstraint;
+import com.djrapitops.plan.system.database.databases.sql.operation.Queries;
 import com.djrapitops.plan.system.database.databases.sql.processing.QueryAllStatement;
 import com.djrapitops.plan.system.database.databases.sql.processing.QueryStatement;
 import com.djrapitops.plan.system.database.databases.sql.statements.TableSqlParser;
@@ -28,6 +30,7 @@ import com.djrapitops.plugin.utilities.Verify;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
+import java.util.List;
 import java.util.UUID;
 
 public abstract class Patch {
@@ -146,71 +149,30 @@ public abstract class Patch {
         }
     }
 
-    protected void dropForeignKey(String table, String referencedTable, String referencedColumn) {
+    protected void dropForeignKeys(String referencedTable) {
         if (dbType != DBType.MYSQL) {
             return;
         }
-        String keyName = getForeignKeyConstraintName(table, referencedTable, referencedColumn);
-        if (keyName == null) {
-            return;
-        }
 
+        String schema = db.getConfig().get(DatabaseSettings.MYSQL_DATABASE);
+        List<ForeignKeyConstraint> constraints = query(Queries.foreignKeyConstraintsOf(schema, referencedTable));
+
+        for (ForeignKeyConstraint constraint : constraints) {
             // Uses information from https://stackoverflow.com/a/34574758
-        db.execute("ALTER TABLE " + table +
+            db.execute("ALTER TABLE " + constraint.getTable() +
-                " DROP FOREIGN KEY " + keyName);
+                    " DROP FOREIGN KEY " + constraint.getConstraintName());
+        }
     }
 
     protected void ensureNoForeignKeyConstraints(String table) {
         if (dbType != DBType.MYSQL) {
             return;
         }
-        String keySQL = "SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE" +
-                " WHERE REFERENCED_TABLE_SCHEMA = ?" +
-                " AND TABLE_NAME = ?";
-        String keyName = query(new QueryStatement<String>(keySQL) {
-            @Override
-            public void prepare(PreparedStatement statement) throws SQLException {
-                statement.setString(1, db.getConfig().get(DatabaseSettings.MYSQL_DATABASE));
-                statement.setString(2, table);
-            }
 
-            @Override
+        String schema = db.getConfig().get(DatabaseSettings.MYSQL_DATABASE);
-            public String processResults(ResultSet set) throws SQLException {
+        List<ForeignKeyConstraint> constraints = query(Queries.foreignKeyConstraintsOf(schema, table));
-                if (set.next()) {
-                    return set.getString("CONSTRAINT_NAME");
-                } else {
-                    return null;
-                }
-            }
-        });
-        Verify.isTrue(keyName == null, () -> new DBOpException("Table '" + table + "' has constraint '" + keyName + "'"));
-    }
 
-    private String getForeignKeyConstraintName(String table, String referencedTable, String referencedColumn) {
+        Verify.isTrue(constraints.isEmpty(), () -> new DBOpException("Table '" + table + "' has constraints '" + constraints + "'"));
-        // Uses information from https://stackoverflow.com/a/201678
-        String keySQL = "SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE" +
-                " WHERE REFERENCED_TABLE_SCHEMA = ?" +
-                " AND TABLE_NAME = ?" +
-                " AND REFERENCED_TABLE_NAME = ?" +
-                " AND REFERENCED_COLUMN_NAME = ?";
-        return query(new QueryStatement<String>(keySQL) {
-            @Override
-            public void prepare(PreparedStatement statement) throws SQLException {
-                statement.setString(1, db.getConfig().get(DatabaseSettings.MYSQL_DATABASE));
-                statement.setString(2, table);
-                statement.setString(3, referencedTable);
-                statement.setString(4, referencedColumn);
-            }
-
-            @Override
-            public String processResults(ResultSet set) throws SQLException {
-                if (set.next()) {
-                    return set.getString("CONSTRAINT_NAME");
-                } else {
-                    return null;
-                }
-            }
-        });
     }
 
     protected UUID getServerUUID() {

Plan/common/src/main/java/com/djrapitops/plan/system/database/databases/sql/patches/SessionsOptimizationPatch.java

@@ -18,10 +18,8 @@ package com.djrapitops.plan.system.database.databases.sql.patches;
 
 import com.djrapitops.plan.api.exceptions.database.DBOpException;
 import com.djrapitops.plan.system.database.databases.sql.SQLDB;
-import com.djrapitops.plan.system.database.databases.sql.tables.KillsTable;
 import com.djrapitops.plan.system.database.databases.sql.tables.SessionsTable;
 import com.djrapitops.plan.system.database.databases.sql.tables.SessionsTable.Col;
-import com.djrapitops.plan.system.database.databases.sql.tables.WorldTimesTable;
 
 public class SessionsOptimizationPatch extends Patch {
 
@@ -46,9 +44,7 @@ public class SessionsOptimizationPatch extends Patch {
     @Override
     public void apply() {
         try {
-            dropForeignKey(WorldTimesTable.TABLE_NAME, tableName, Col.ID.get());
+            dropForeignKeys(tableName);
-            dropForeignKey(KillsTable.TABLE_NAME, tableName, Col.ID.get());
-
             ensureNoForeignKeyConstraints(tableName);
 
             tempOldTable();

Plan/common/src/main/java/com/djrapitops/plan/system/database/databases/sql/patches/WorldsOptimizationPatch.java

@@ -20,7 +20,6 @@ import com.djrapitops.plan.api.exceptions.database.DBOpException;
 import com.djrapitops.plan.system.database.databases.sql.SQLDB;
 import com.djrapitops.plan.system.database.databases.sql.tables.WorldTable;
 import com.djrapitops.plan.system.database.databases.sql.tables.WorldTable.Col;
-import com.djrapitops.plan.system.database.databases.sql.tables.WorldTimesTable;
 
 public class WorldsOptimizationPatch extends Patch {
 
@@ -44,8 +43,7 @@ public class WorldsOptimizationPatch extends Patch {
     @Override
     public void apply() {
         try {
-            dropForeignKey(WorldTimesTable.TABLE_NAME, tableName, Col.ID.get());
+            dropForeignKeys(tableName);
-
             ensureNoForeignKeyConstraints(tableName);
 
             tempOldTable();