Merge pull request #916 from katzyn/information_schema

Implement TABLE_CONSTRAINTS and REFERENTIAL_CONSTRAINTS from the SQL standard

h2/src/main/org/h2/constraint/Constraint.java

@@ -39,7 +39,23 @@ public abstract class Constraint extends SchemaObjectBase implements
         /**
          * The constraint type for referential constraints.
          */
-        REFERENTIAL
+        REFERENTIAL;
+
+        /**
+         * Get standard SQL type name.
+         *
+         * @return standard SQL type name
+         */
+        public String getSqlName() {
+            if (this == Constraint.Type.PRIMARY_KEY) {
+                return "PRIMARY KEY";
+            }
+            if (this == Constraint.Type.REFERENTIAL) {
+                return "FOREIGN KEY";
+            }
+            return name();
+        }
+
     }
 
     /**

h2/src/main/org/h2/constraint/ConstraintActionType.java

@@ -24,5 +24,21 @@ public enum ConstraintActionType {
     /**
      * The action is to set the value to NULL.
      */
-    SET_NULL
+    SET_NULL;
+
+    /**
+     * Get standard SQL type name.
+     *
+     * @return standard SQL type name
+     */
+    public String getSqlName() {
+        if (this == ConstraintActionType.SET_DEFAULT) {
+            return "SET DEFAULT";
+        }
+        if (this == SET_NULL) {
+            return "SET NULL";
+        }
+        return name();
+    }
+
 }
\ No newline at end of file

h2/src/main/org/h2/constraint/ConstraintReferential.java

@@ -54,22 +54,6 @@ public class ConstraintReferential extends Constraint {
         return Constraint.Type.REFERENTIAL;
     }
 
-    private static void appendAction(StatementBuilder buff, ConstraintActionType action) {
-        switch (action) {
-        case CASCADE:
-            buff.append("CASCADE");
-            break;
-        case SET_DEFAULT:
-            buff.append("SET DEFAULT");
-            break;
-        case SET_NULL:
-            buff.append("SET NULL");
-            break;
-        default:
-            DbException.throwInternalError("action=" + action);
-        }
-    }
-
     /**
      * Create the SQL statement of this object so a copy of the table can be
      * made.
@@ -135,12 +119,10 @@ public class ConstraintReferential extends Constraint {
             buff.append(" INDEX ").append(refIndex.getSQL());
         }
         if (deleteAction != ConstraintActionType.RESTRICT) {
-            buff.append(" ON DELETE ");
-            appendAction(buff, deleteAction);
+            buff.append(" ON DELETE ").append(deleteAction.getSqlName());
         }
         if (updateAction != ConstraintActionType.RESTRICT) {
-            buff.append(" ON UPDATE ");
-            appendAction(buff, updateAction);
+            buff.append(" ON UPDATE ").append(updateAction.getSqlName());
         }
         return buff.append(" NOCHECK").toString();
     }

h2/src/main/org/h2/constraint/ConstraintUnique.java

@@ -54,7 +54,7 @@ public class ConstraintUnique extends Constraint {
         if (comment != null) {
             buff.append(" COMMENT ").append(StringUtils.quoteStringSQL(comment));
         }
-        buff.append(' ').append(getTypeName()).append('(');
+        buff.append(' ').append(getConstraintType().getSqlName()).append('(');
         for (IndexColumn c : columns) {
             buff.appendExceptFirst(", ");
             buff.append(Parser.quoteIdentifier(c.column.getName()));
@@ -66,13 +66,6 @@ public class ConstraintUnique extends Constraint {
         return buff.toString();
     }
 
-    private String getTypeName() {
-        if (primaryKey) {
-            return "PRIMARY KEY";
-        }
-        return "UNIQUE";
-    }
-
     @Override
     public String getCreateSQLWithoutIndexes() {
         return getCreateSQLForCopy(table, getSQL(), false);

h2/src/main/org/h2/table/MetaTable.java

@@ -110,8 +110,10 @@ public class MetaTable extends Table {
     private static final int SESSION_STATE = 27;
     private static final int QUERY_STATISTICS = 28;
     private static final int SYNONYMS = 29;
-    private static final int KEY_COLUMN_USAGE = 30;
-    private static final int META_TABLE_TYPE_COUNT = KEY_COLUMN_USAGE + 1;
+    private static final int TABLE_CONSTRAINTS = 30;
+    private static final int KEY_COLUMN_USAGE = 31;
+    private static final int REFERENTIAL_CONSTRAINTS = 32;
+    private static final int META_TABLE_TYPE_COUNT = REFERENTIAL_CONSTRAINTS + 1;
 
     private final int type;
     private final int indexColumn;
@@ -558,6 +560,22 @@ public class MetaTable extends Table {
             indexColumnName = "SYNONYM_NAME";
             break;
         }
+        case TABLE_CONSTRAINTS: {
+            setObjectName("TABLE_CONSTRAINTS");
+            cols = createColumns(
+                    "CONSTRAINT_CATALOG",
+                    "CONSTRAINT_SCHEMA",
+                    "CONSTRAINT_NAME",
+                    "CONSTRAINT_TYPE",
+                    "TABLE_CATALOG",
+                    "TABLE_SCHEMA",
+                    "TABLE_NAME",
+                    "IS_DEFERRABLE",
+                    "INITIALLY_DEFERRED"
+            );
+            indexColumnName = "TABLE_NAME";
+            break;
+        }
         case KEY_COLUMN_USAGE: {
             setObjectName("KEY_COLUMN_USAGE");
             cols = createColumns(
@@ -574,6 +592,21 @@ public class MetaTable extends Table {
             indexColumnName = "TABLE_NAME";
             break;
         }
+        case REFERENTIAL_CONSTRAINTS: {
+            setObjectName("REFERENTIAL_CONSTRAINTS");
+            cols = createColumns(
+                    "CONSTRAINT_CATALOG",
+                    "CONSTRAINT_SCHEMA",
+                    "CONSTRAINT_NAME",
+                    "UNIQUE_CONSTRAINT_CATALOG",
+                    "UNIQUE_CONSTRAINT_SCHEMA",
+                    "UNIQUE_CONSTRAINT_NAME",
+                    "MATCH_OPTION",
+                    "UPDATE_RULE",
+                    "DELETE_RULE"
+            );
+            break;
+        }
         default:
             throw DbException.throwInternalError("type="+type);
         }
@@ -1924,9 +1957,43 @@ public class MetaTable extends Table {
             }
             break;
         }
+        case TABLE_CONSTRAINTS: {
+            for (SchemaObject obj : database.getAllSchemaObjects(DbObject.CONSTRAINT)) {
+                Constraint constraint = (Constraint) obj;
+                Constraint.Type constraintType = constraint.getConstraintType();
+                Table table = constraint.getTable();
+                if (hideTable(table, session)) {
+                    continue;
+                }
+                String tableName = identifier(table.getName());
+                if (!checkIndex(session, tableName, indexFrom, indexTo)) {
+                    continue;
+                }
+                add(rows,
+                        // CONSTRAINT_CATALOG
+                        catalog,
+                        // CONSTRAINT_SCHEMA
+                        identifier(constraint.getSchema().getName()),
+                        // CONSTRAINT_NAME
+                        identifier(constraint.getName()),
+                        // CONSTRAINT_TYPE
+                        constraintType.getSqlName(),
+                        // TABLE_CATALOG
+                        catalog,
+                        // TABLE_SCHEMA
+                        identifier(table.getSchema().getName()),
+                        // TABLE_NAME
+                        tableName,
+                        // IS_DEFERRABLE
+                        "NO",
+                        // INITIALLY_DEFERRED
+                        "NO"
+                );
+            }
+            break;
+        }
         case KEY_COLUMN_USAGE: {
-            for (SchemaObject obj : database.getAllSchemaObjects(
-                    DbObject.CONSTRAINT)) {
+            for (SchemaObject obj : database.getAllSchemaObjects(DbObject.CONSTRAINT)) {
                 Constraint constraint = (Constraint) obj;
                 Constraint.Type constraintType = constraint.getConstraintType();
                 IndexColumn[] indexColumns = null;
@@ -1947,9 +2014,31 @@ public class MetaTable extends Table {
                 if (indexColumns == null) {
                     continue;
                 }
+                ConstraintUnique referenced;
+                if (constraintType == Constraint.Type.REFERENTIAL) {
+                    referenced = lookupUniqueForReferential((ConstraintReferential) constraint);
+                } else {
+                    referenced = null;
+                }
                 for (int i = 0; i < indexColumns.length; i++) {
                     IndexColumn indexColumn = indexColumns[i];
                     String ordinalPosition = Integer.toString(i + 1);
+                    String positionInUniqueConstraint;
+                    if (constraintType == Constraint.Type.REFERENTIAL) {
+                        positionInUniqueConstraint = ordinalPosition;
+                        if (referenced != null) {
+                            Column c = ((ConstraintReferential) constraint).getRefColumns()[i].column;
+                            IndexColumn[] refColumns = referenced.getColumns();
+                            for (int j = 0; j < refColumns.length; j++) {
+                                if (refColumns[j].column.equals(c)) {
+                                    positionInUniqueConstraint = Integer.toString(j + 1);
+                                    break;
+                                }
+                            }
+                        }
+                    } else {
+                        positionInUniqueConstraint = null;
+                    }
                     add(rows,
                             // CONSTRAINT_CATALOG
                             catalog,
@@ -1968,9 +2057,49 @@ public class MetaTable extends Table {
                             // ORDINAL_POSITION
                             ordinalPosition,
                             // POSITION_IN_UNIQUE_CONSTRAINT
-                            (constraintType == Constraint.Type.REFERENTIAL ? ordinalPosition : null)
-                        );
+                            positionInUniqueConstraint
+                    );
+                }
+            }
+            break;
+        }
+        case REFERENTIAL_CONSTRAINTS: {
+            for (SchemaObject obj : database.getAllSchemaObjects(DbObject.CONSTRAINT)) {
+                if (((Constraint) obj).getConstraintType() != Constraint.Type.REFERENTIAL) {
+                    continue;
                 }
+                ConstraintReferential constraint = (ConstraintReferential) obj;
+                Table table = constraint.getTable();
+                if (hideTable(table, session)) {
+                    continue;
+                }
+                // Should be referenced unique constraint, but H2 uses indexes instead.
+                // So try to find matching unique constraint first and there is no such
+                // constraint use index name to return something.
+                SchemaObject unique = lookupUniqueForReferential(constraint);
+                if (unique == null) {
+                    unique = constraint.getUniqueIndex();
+                }
+                add(rows,
+                        // CONSTRAINT_CATALOG
+                        catalog,
+                        // CONSTRAINT_SCHEMA
+                        identifier(constraint.getSchema().getName()),
+                        // CONSTRAINT_NAME
+                        identifier(constraint.getName()),
+                        // UNIQUE_CONSTRAINT_CATALOG
+                        catalog,
+                        // UNIQUE_CONSTRAINT_SCHEMA
+                        identifier(unique.getSchema().getName()),
+                        // UNIQUE_CONSTRAINT_NAME
+                        unique.getName(),
+                        // MATCH_OPTION
+                        "NONE",
+                        // UPDATE_RULE
+                        constraint.getUpdateAction().getSqlName(),
+                        // DELETE_RULE
+                        constraint.getDeleteAction().getSqlName()
+                );
             }
             break;
         }
@@ -1995,6 +2124,19 @@ public class MetaTable extends Table {
         }
     }
 
+    private static ConstraintUnique lookupUniqueForReferential(ConstraintReferential referential) {
+        Table table = referential.getRefTable();
+        for (Constraint c : table.getConstraints()) {
+            if (c.getConstraintType() == Constraint.Type.UNIQUE) {
+                ConstraintUnique unique = (ConstraintUnique) c;
+                if (unique.getReferencedColumns(table).equals(referential.getReferencedColumns(table))) {
+                    return unique;
+                }
+            }
+        }
+        return null;
+    }
+
     @Override
     public void removeRow(Session session, Row row) {
         throw DbException.getUnsupportedException("META");

h2/src/test/org/h2/test/jdbc/TestMetaData.java

@@ -1090,6 +1090,8 @@ public class TestMetaData extends TestBase {
         rs.next();
         assertEquals("QUERY_STATISTICS", rs.getString("TABLE_NAME"));
         rs.next();
+        assertEquals("REFERENTIAL_CONSTRAINTS", rs.getString("TABLE_NAME"));
+        rs.next();
         assertEquals("RIGHTS", rs.getString("TABLE_NAME"));
         rs.next();
         assertEquals("ROLES", rs.getString("TABLE_NAME"));
@@ -1108,6 +1110,8 @@ public class TestMetaData extends TestBase {
         rs.next();
         assertEquals("TABLES", rs.getString("TABLE_NAME"));
         rs.next();
+        assertEquals("TABLE_CONSTRAINTS", rs.getString("TABLE_NAME"));
+        rs.next();
         assertEquals("TABLE_PRIVILEGES", rs.getString("TABLE_NAME"));
         rs.next();
         assertEquals("TABLE_TYPES", rs.getString("TABLE_NAME"));

h2/src/test/org/h2/test/scripts/information_schema.sql

@@ -15,9 +15,32 @@ ALTER TABLE T1 ADD CONSTRAINT U_1 UNIQUE(C3, C4);
 CREATE TABLE T2(C1 INT, C2 INT, C3 INT, C4 INT);
 > ok
 
-ALTER TABLE T2 ADD CONSTRAINT FK_1 FOREIGN KEY (C3, C4) REFERENCES T1(C1, C3);
+ALTER TABLE T2 ADD CONSTRAINT FK_1 FOREIGN KEY (C3, C4) REFERENCES T1(C1, C3) ON DELETE SET NULL;
 > ok
 
+ALTER TABLE T2 ADD CONSTRAINT FK_2 FOREIGN KEY (C3, C4) REFERENCES T1(C4, C3) ON UPDATE CASCADE ON DELETE SET DEFAULT;
+> ok
+
+ALTER TABLE T2 ADD CONSTRAINT CH_1 CHECK C4 > 0;
+> ok
+
+SELECT * FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS LIMIT 0;
+> CONSTRAINT_CATALOG CONSTRAINT_SCHEMA CONSTRAINT_NAME CONSTRAINT_TYPE TABLE_CATALOG TABLE_SCHEMA TABLE_NAME IS_DEFERRABLE INITIALLY_DEFERRED
+> ------------------ ----------------- --------------- --------------- ------------- ------------ ---------- ------------- ------------------
+> rows: 0
+
+SELECT CONSTRAINT_NAME, CONSTRAINT_TYPE, TABLE_NAME, IS_DEFERRABLE, INITIALLY_DEFERRED FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
+    WHERE CONSTRAINT_CATALOG = DATABASE() AND CONSTRAINT_SCHEMA = SCHEMA() AND TABLE_CATALOG = DATABASE() AND TABLE_SCHEMA = SCHEMA()
+    ORDER BY TABLE_NAME, CONSTRAINT_NAME;
+> CONSTRAINT_NAME CONSTRAINT_TYPE TABLE_NAME IS_DEFERRABLE INITIALLY_DEFERRED
+> --------------- --------------- ---------- ------------- ------------------
+> PK_1            PRIMARY KEY     T1         NO            NO
+> U_1             UNIQUE          T1         NO            NO
+> CH_1            CHECK           T2         NO            NO
+> FK_1            FOREIGN KEY     T2         NO            NO
+> FK_2            FOREIGN KEY     T2         NO            NO
+> rows (ordered): 5
+
 SELECT * FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE LIMIT 0;
 > CONSTRAINT_CATALOG CONSTRAINT_SCHEMA CONSTRAINT_NAME TABLE_CATALOG TABLE_SCHEMA TABLE_NAME COLUMN_NAME ORDINAL_POSITION POSITION_IN_UNIQUE_CONSTRAINT
 > ------------------ ----------------- --------------- ------------- ------------ ---------- ----------- ---------------- -----------------------------
@@ -34,7 +57,34 @@ SELECT CONSTRAINT_NAME, TABLE_NAME, COLUMN_NAME, ORDINAL_POSITION, POSITION_IN_U
 > U_1             T1         C4          2                null
 > FK_1            T2         C3          1                1
 > FK_1            T2         C4          2                2
-> rows (ordered): 6
+> FK_2            T2         C3          1                2
+> FK_2            T2         C4          2                1
+> rows (ordered): 8
+
+SELECT * FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS LIMIT 0;
+> CONSTRAINT_CATALOG CONSTRAINT_SCHEMA CONSTRAINT_NAME UNIQUE_CONSTRAINT_CATALOG UNIQUE_CONSTRAINT_SCHEMA UNIQUE_CONSTRAINT_NAME MATCH_OPTION UPDATE_RULE DELETE_RULE
+> ------------------ ----------------- --------------- ------------------------- ------------------------ ---------------------- ------------ ----------- -----------
+> rows: 0
+
+-- H2 may return name of the index istead of name of the referenced constraint as UNIQUE_CONSTRAINT_NAME
+SELECT CONSTRAINT_NAME, SUBSTRING(UNIQUE_CONSTRAINT_NAME, 0, 11) AS UCN_PART, MATCH_OPTION, UPDATE_RULE, DELETE_RULE FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS
+    WHERE CONSTRAINT_CATALOG = DATABASE() AND CONSTRAINT_SCHEMA = SCHEMA() AND UNIQUE_CONSTRAINT_CATALOG = DATABASE() AND UNIQUE_CONSTRAINT_SCHEMA = SCHEMA()
+    ORDER BY CONSTRAINT_NAME, UNIQUE_CONSTRAINT_NAME;
+> CONSTRAINT_NAME UCN_PART    MATCH_OPTION UPDATE_RULE DELETE_RULE
+> --------------- ----------- ------------ ----------- -----------
+> FK_1            FK_1_INDEX_ NONE         RESTRICT    SET NULL
+> FK_2            U_1         NONE         CASCADE     SET DEFAULT
+> rows (ordered): 2
+
+SELECT U1.TABLE_NAME T1, U1.COLUMN_NAME C1, U2.TABLE_NAME T2, U2.COLUMN_NAME C2
+    FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE U1 JOIN INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS RC ON U1.CONSTRAINT_NAME = RC.CONSTRAINT_NAME
+    JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE U2 ON RC.UNIQUE_CONSTRAINT_NAME = U2.CONSTRAINT_NAME AND U1.POSITION_IN_UNIQUE_CONSTRAINT = U2.ORDINAL_POSITION
+    WHERE U1.CONSTRAINT_NAME = 'FK_2' ORDER BY U1.COLUMN_NAME;
+> T1 C1 T2 C2
+> -- -- -- --
+> T2 C3 T1 C4
+> T2 C4 T1 C3
+> rows (ordered): 2
 
 DROP TABLE T2;
 > ok