/*
 Copyright (C) 2005-2007 MySQL AB

 This program is free software; you can redistribute it and/or modify
 it under the terms of version 2 of the GNU General Public License as 
 published by the Free Software Foundation.

 There are special exceptions to the terms and conditions of the GPL 
 as it is applied to this software. View the full text of the 
 exception in file EXCEPTIONS-CONNECTOR-J in the directory of this 
 software distribution.

 This program 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 General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */
package com.mysql.jdbc;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

/**
 * DatabaseMetaData implementation that uses INFORMATION_SCHEMA available in
 * MySQL-5.0 and newer.
 * 
 * The majority of the queries in this code were built for Connector/OO.org by
 * Georg Richter (georg_at_mysql.com).
 */
public class DatabaseMetaDataUsingInfoSchema extends DatabaseMetaData {

	private boolean hasReferentialConstraintsView;

	protected DatabaseMetaDataUsingInfoSchema(ConnectionImpl connToSet,
			String databaseToSet) throws SQLException {
		super(connToSet, databaseToSet);
		
		this.hasReferentialConstraintsView = 
			this.conn.versionMeetsMinimum(5, 1, 10);
	}

	private ResultSet executeMetadataQuery(PreparedStatement pStmt)
			throws SQLException {
		ResultSet rs = pStmt.executeQuery();
		((com.mysql.jdbc.ResultSetInternalMethods) rs).setOwningStatement(null);

		return rs;
	}

	/**
	 * Get a description of the access rights for a table's columns.
	 * <P>
	 * Only privileges matching the column name criteria are returned. They are
	 * ordered by COLUMN_NAME and PRIVILEGE.
	 * </p>
	 * <P>
	 * Each privilige description has the following columns:
	 * <OL>
	 * <li> <B>TABLE_CAT</B> String => table catalog (may be null) </li>
	 * <li> <B>TABLE_SCHEM</B> String => table schema (may be null) </li>
	 * <li> <B>TABLE_NAME</B> String => table name </li>
	 * <li> <B>COLUMN_NAME</B> String => column name </li>
	 * <li> <B>GRANTOR</B> => grantor of access (may be null) </li>
	 * <li> <B>GRANTEE</B> String => grantee of access </li>
	 * <li> <B>PRIVILEGE</B> String => name of access (SELECT, INSERT, UPDATE,
	 * REFRENCES, ...) </li>
	 * <li> <B>IS_GRANTABLE</B> String => "YES" if grantee is permitted to
	 * grant to others; "NO" if not; null if unknown </li>
	 * </ol>
	 * </p>
	 * 
	 * @param catalog
	 *            a catalog name; "" retrieves those without a catalog
	 * @param schema
	 *            a schema name; "" retrieves those without a schema
	 * @param table
	 *            a table name
	 * @param columnNamePattern
	 *            a column name pattern
	 * @return ResultSet each row is a column privilege description
	 * @throws SQLException
	 *             if a database access error occurs
	 * @see #getSearchStringEscape
	 */
	public java.sql.ResultSet getColumnPrivileges(String catalog,
			String schema, String table, String columnNamePattern)
			throws SQLException {
		if (columnNamePattern == null) {
			if (this.conn.getNullNamePatternMatchesAll()) {
				columnNamePattern = "%";
			} else {
				throw SQLError.createSQLException(
						"Column name pattern can not be NULL or empty.",
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
			}
		}

		if (catalog == null) {
			if (this.conn.getNullCatalogMeansCurrent()) {
				catalog = this.database;
			}	
		}
		
		String sql = "SELECT TABLE_SCHEMA AS TABLE_CAT, NULL AS TABLE_SCHEM, TABLE_NAME,"
			 +"COLUMN_NAME, NULL AS GRANTOR, GRANTEE, PRIVILEGE_TYPE AS PRIVILEGE, IS_GRANTABLE FROM "
			 + "INFORMATION_SCHEMA.COLUMN_PRIVILEGES WHERE "
			 + "TABLE_SCHEMA LIKE ? AND "
			 + "TABLE_NAME =? AND COLUMN_NAME LIKE ? ORDER BY " 
			 + "COLUMN_NAME, PRIVILEGE_TYPE";
		
		PreparedStatement pStmt = null;
		
		try {
			pStmt = prepareMetaDataSafeStatement(sql);
			
			if (catalog != null) {
				pStmt.setString(1, catalog);
			} else {
				pStmt.setString(1, "%");
			}
			
			pStmt.setString(2, table);
			pStmt.setString(3, columnNamePattern);
			
			ResultSet rs = executeMetadataQuery(pStmt);
			((com.mysql.jdbc.ResultSetInternalMethods) rs).redefineFieldsForDBMD(new Field[] {
					new Field("", "TABLE_CAT", Types.CHAR, 64),
					new Field("", "TABLE_SCHEM", Types.CHAR, 1),
					new Field("", "TABLE_NAME", Types.CHAR, 64),
					new Field("", "COLUMN_NAME", Types.CHAR, 64),
					new Field("", "GRANTOR", Types.CHAR, 77),
					new Field("", "GRANTEE", Types.CHAR, 77),
					new Field("", "PRIVILEGE", Types.CHAR, 64),
					new Field("", "IS_GRANTABLE", Types.CHAR, 3)});
			
			return rs;
		} finally {
			if (pStmt != null) {
				pStmt.close();
			}
		}
	}

	/**
	 * Get a description of table columns available in a catalog.
	 * <P>
	 * Only column descriptions matching the catalog, schema, table and column
	 * name criteria are returned. They are ordered by TABLE_SCHEM, TABLE_NAME
	 * and ORDINAL_POSITION.
	 * </p>
	 * <P>
	 * Each column description has the following columns:
	 * <OL>
	 * <li> <B>TABLE_CAT</B> String => table catalog (may be null) </li>
	 * <li> <B>TABLE_SCHEM</B> String => table schema (may be null) </li>
	 * <li> <B>TABLE_NAME</B> String => table name </li>
	 * <li> <B>COLUMN_NAME</B> String => column name </li>
	 * <li> <B>DATA_TYPE</B> short => SQL type from java.sql.Types </li>
	 * <li> <B>TYPE_NAME</B> String => Data source dependent type name </li>
	 * <li> <B>COLUMN_SIZE</B> int => column size. For char or date types this
	 * is the maximum number of characters, for numeric or decimal types this is
	 * precision. </li>
	 * <li> <B>BUFFER_LENGTH</B> is not used. </li>
	 * <li> <B>DECIMAL_DIGITS</B> int => the number of fractional digits </li>
	 * <li> <B>NUM_PREC_RADIX</B> int => Radix (typically either 10 or 2) </li>
	 * <li> <B>NULLABLE</B> int => is NULL allowed?
	 * <UL>
	 * <li> columnNoNulls - might not allow NULL values </li>
	 * <li> columnNullable - definitely allows NULL values </li>
	 * <li> columnNullableUnknown - nullability unknown </li>
	 * </ul>
	 * </li>
	 * <li> <B>REMARKS</B> String => comment describing column (may be null)
	 * </li>
	 * <li> <B>COLUMN_DEF</B> String => default value (may be null) </li>
	 * <li> <B>SQL_DATA_TYPE</B> int => unused </li>
	 * <li> <B>SQL_DATETIME_SUB</B> int => unused </li>
	 * <li> <B>CHAR_OCTET_LENGTH</B> int => for char types the maximum number
	 * of bytes in the column </li>
	 * <li> <B>ORDINAL_POSITION</B> int => index of column in table (starting
	 * at 1) </li>
	 * <li> <B>IS_NULLABLE</B> String => "NO" means column definitely does not
	 * allow NULL values; "YES" means the column might allow NULL values. An
	 * empty string means nobody knows. </li>
	 * </ol>
	 * </p>
	 */
	public ResultSet getColumns(String catalog, String schemaPattern,
			String tableName, String columnNamePattern) throws SQLException {
		if (columnNamePattern == null) {
			if (this.conn.getNullNamePatternMatchesAll()) {
				columnNamePattern = "%";
			} else {
				throw SQLError.createSQLException(
						"Column name pattern can not be NULL or empty.",
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
			}
		}

		if (catalog == null) {
			if (this.conn.getNullCatalogMeansCurrent()) {
				catalog = this.database;
			}
		}

		StringBuffer sqlBuf = new StringBuffer("SELECT "
				+ "TABLE_SCHEMA AS TABLE_CAT, " + "NULL AS TABLE_SCHEM,"
				+ "TABLE_NAME," + "COLUMN_NAME,");
		MysqlDefs.appendJdbcTypeMappingQuery(sqlBuf, "DATA_TYPE");

		sqlBuf.append(" AS DATA_TYPE, ");

		if (conn.getCapitalizeTypeNames()) {
			sqlBuf.append("UPPER(CASE WHEN LOCATE('unsigned', COLUMN_TYPE) != 0 AND LOCATE('unsigned', DATA_TYPE) = 0 THEN CONCAT(DATA_TYPE, ' unsigned') ELSE DATA_TYPE END) AS TYPE_NAME,");
		} else {
			sqlBuf.append("CASE WHEN LOCATE('unsigned', COLUMN_TYPE) != 0 AND LOCATE('unsigned', DATA_TYPE) = 0 THEN CONCAT(DATA_TYPE, ' unsigned') ELSE DATA_TYPE END AS TYPE_NAME,");
		}

		sqlBuf
				.append("CASE WHEN CHARACTER_MAXIMUM_LENGTH IS NULL THEN NUMERIC_PRECISION ELSE CASE WHEN CHARACTER_MAXIMUM_LENGTH > " 
						+ Integer.MAX_VALUE + " THEN " + Integer.MAX_VALUE + 
						" ELSE CHARACTER_MAXIMUM_LENGTH END END AS COLUMN_SIZE, "
						+ MysqlIO.getMaxBuf() + " AS BUFFER_LENGTH,"
						+ "NUMERIC_SCALE AS DECIMAL_DIGITS,"
						+ "10 AS NUM_PREC_RADIX,"
						+ "CASE WHEN IS_NULLABLE='NO' THEN " + columnNoNulls + " ELSE CASE WHEN IS_NULLABLE='YES' THEN " + columnNullable + " ELSE " + columnNullableUnknown + " END END AS NULLABLE,"
						+ "COLUMN_COMMENT AS REMARKS,"
						+ "COLUMN_DEFAULT AS COLUMN_DEF,"
						+ "0 AS SQL_DATA_TYPE,"
						+ "0 AS SQL_DATETIME_SUB,"
						+ "CASE WHEN CHARACTER_OCTET_LENGTH > " + Integer.MAX_VALUE + " THEN " + Integer.MAX_VALUE + " ELSE CHARACTER_OCTET_LENGTH END AS CHAR_OCTET_LENGTH,"
						+ "ORDINAL_POSITION,"
						+ "IS_NULLABLE,"
						+ "NULL AS SCOPE_CATALOG,"
						+ "NULL AS SCOPE_SCHEMA,"
						+ "NULL AS SCOPE_TABLE,"
						+ "NULL AS SOURCE_DATA_TYPE,"
						+ "IF (EXTRA LIKE '%auto_increment%','YES','NO') AS IS_AUTOINCREMENT "
						+ "FROM INFORMATION_SCHEMA.COLUMNS WHERE "
						+ "TABLE_SCHEMA LIKE ? AND "
						+ "TABLE_NAME LIKE ? AND COLUMN_NAME LIKE ? "
						+ "ORDER BY TABLE_SCHEMA, TABLE_NAME, ORDINAL_POSITION");

		PreparedStatement pStmt = null;

		try {
			pStmt = prepareMetaDataSafeStatement(sqlBuf.toString());
			
			if (catalog != null) {
				pStmt.setString(1, catalog);
			} else {
				pStmt.setString(1, "%");
			}
			
			pStmt.setString(2, tableName);
			pStmt.setString(3, columnNamePattern);

			ResultSet rs = executeMetadataQuery(pStmt);

			((com.mysql.jdbc.ResultSetInternalMethods) rs).redefineFieldsForDBMD(new Field[] {
					new Field("", "TABLE_CAT", Types.CHAR, 255),
					new Field("", "TABLE_SCHEM", Types.CHAR, 0),
					new Field("", "TABLE_NAME", Types.CHAR, 255),
					new Field("", "COLUMN_NAME", Types.CHAR, 32),
					new Field("", "DATA_TYPE", Types.SMALLINT, 5),
					new Field("", "TYPE_NAME", Types.CHAR, 16),
					new Field("", "COLUMN_SIZE", Types.INTEGER, Integer
							.toString(Integer.MAX_VALUE).length()),
					new Field("", "BUFFER_LENGTH", Types.INTEGER, 10),
					new Field("", "DECIMAL_DIGITS", Types.INTEGER, 10),
					new Field("", "NUM_PREC_RADIX", Types.INTEGER, 10),
					new Field("", "NULLABLE", Types.INTEGER, 10),
					new Field("", "REMARKS", Types.CHAR, 0),
					new Field("", "COLUMN_DEF", Types.CHAR, 0),
					new Field("", "SQL_DATA_TYPE", Types.INTEGER, 10),
					new Field("", "SQL_DATETIME_SUB", Types.INTEGER, 10),
					new Field("", "CHAR_OCTET_LENGTH", Types.INTEGER, Integer
							.toString(Integer.MAX_VALUE).length()),
					new Field("", "ORDINAL_POSITION", Types.INTEGER, 10),
					new Field("", "IS_NULLABLE", Types.CHAR, 3),
					new Field("", "SCOPE_CATALOG", Types.CHAR, 255),
					new Field("", "SCOPE_SCHEMA", Types.CHAR, 255),
					new Field("", "SCOPE_TABLE", Types.CHAR, 255),
					new Field("", "SOURCE_DATA_TYPE", Types.SMALLINT, 10),
					new Field("", "IS_AUTOINCREMENT", Types.CHAR, 3) });
			return rs;
		} finally {
			if (pStmt != null) {
				pStmt.close();
			}
		}
	}

	/**
	 * Get a description of the foreign key columns in the foreign key table
	 * that reference the primary key columns of the primary key table (describe
	 * how one table imports another's key.) This should normally return a
	 * single foreign key/primary key pair (most tables only import a foreign
	 * key from a table once.) They are ordered by FKTABLE_CAT, FKTABLE_SCHEM,
	 * FKTABLE_NAME, and KEY_SEQ.
	 * <P>
	 * Each foreign key column description has the following columns:
	 * <OL>
	 * <li> <B>PKTABLE_CAT</B> String => primary key table catalog (may be
	 * null) </li>