+
−/*
+
− * SPDX-License-Identifier: MPL-2.0
+
− *
+
− * This Source Code Form is subject to the terms of the Mozilla Public
+
− * License, v. 2.0.  If a copy of the MPL was not distributed with this
+
− * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
− *
+
− * Copyright 2024, 2025 MonetDB Foundation;
+
− * Copyright August 2008 - 2023 MonetDB B.V.;
+
− * Copyright 1997 - July 2008 CWI.
+
− */
+
−
+
−package org.monetdb.jdbc;
+
−
+
−import java.sql.ResultSetMetaData;
+
−import java.sql.SQLException;
+
−import java.sql.Types;
+
−
+
−/**
+
− *<pre>
+
− * A {@link ResultSetMetaData} suitable for the MonetDB database.
+
− *
+
− * An object that can be used to get information about the types and
+
− * properties of the columns in a ResultSet object.
+
− *</pre>
+
− *
+
− * @author Martin van Dinther
+
− * @version 1.0
+
− */
+
−final class MonetResultSetMetaData
+
−	extends MonetWrapper
+
−	implements ResultSetMetaData
+
−{
+
−	/** The parental Connection object */
+
−	private final MonetConnection conn;
+
−
+
−	/** The number of columns, it can be zero !! */
+
−	private final int colCount;
+
−
+
−	/** The schema names of the columns in this ResultSet */
+
−	private final String[] schemas;
+
−	/** The table names of the columns in this ResultSet */
+
−	private final String[] tables;
+
−	/** The names of the columns in this ResultSet */
+
−	private final String[] columns;
+
−	/** The MonetDB type names of the columns in this ResultSet */
+
−	private final String[] types;
+
−	/** The JDBC SQL type codes of the columns in this ResultSet.
+
−	  * The content will be derived once from the MonetDB String[] types */
+
−	private final int[] JdbcSQLTypes;
+
−	/** The lengths of the columns in this ResultSet */
+
−	private final int[] lengths;
+
−	/** The precisions of the columns in this ResultSet */
+
−	private final int[] precisions;
+
−	/** The scales of the columns in this ResultSet */
+
−	private final int[] scales;
+
−
+
−	/**
+
−	 * For the methods: isNullable() and isAutoIncrement(), we need to query the server.
+
−	 * To do this efficiently we query many columns combined in one SELECT
+
−	 * query and cache the results in following arrays.
+
−	 */
+
−	private final int array_size;
+
−	/** Whether info for a column is already queried or not */
+
−	private final boolean[] _is_queried;
+
−	/** Whether info for a column is already fetched or not */
+
−	private final boolean[] _is_fetched;
+
−	/** The nullability of the columns in this ResultSet */
+
−	private final int[] _isNullable;
+
−	/** The auto increment property of the columns in this ResultSet */
+
−	private final boolean[] _isAutoincrement;
+
−	/** an upper bound value to calculate the range of columns to query */
+
−	private int nextUpperbound;
+
−
+
−
+
−	/**
+
−	 * Main constructor backed by the given connection and header.
+
−	 *
+
−	 * @param connection the parent connection
+
−	 * @param header a ResultSetResponse containing the metadata
+
−	 * @throws IllegalArgumentException if called with null for one of the arguments
+
−	 */
+
−	MonetResultSetMetaData(
+
−		final MonetConnection connection,
+
−		final MonetConnection.ResultSetResponse header)
+
−		throws IllegalArgumentException
+
−	{
+
−		if (connection == null) {
+
−			throw new IllegalArgumentException("Connection may not be null!");
+
−		}
+
−		if (header == null) {
+
−			throw new IllegalArgumentException("Header may not be null!");
+
−		}
+
−		this.conn = connection;
+
−		schemas = header.getSchemaNames();
+
−		tables = header.getTableNames();
+
−		columns = header.getNames();
+
−		types = header.getTypes();
+
−		lengths = header.getColumnLengths();
+
−		precisions = header.getColumnPrecisions();
+
−		scales = header.getColumnScales();
+
−		if (schemas == null) {
+
−			throw new IllegalArgumentException("Schemas may not be null!");
+
−		}
+
−		if (tables == null) {
+
−			throw new IllegalArgumentException("Tables may not be null!");
+
−		}
+
−		if (columns == null) {
+
−			throw new IllegalArgumentException("Columns may not be null!");
+
−		}
+
−		if (types == null) {
+
−			throw new IllegalArgumentException("MonetDB Types may not be null!");
+
−		}
+
−		if (lengths == null) {
+
−			throw new IllegalArgumentException("Lengths may not be null!");
+
−		}
+
−		// Note: the precisions and scales arrays are null when the statement is a PLAN, EXPLAIN or TRACE statement !!
+
−
+
−		colCount = columns.length;
+
−		if (columns.length != tables.length || columns.length != types.length ) {
+
−			throw new IllegalArgumentException("Inconsistent Header metadata");
+
−		}
+
−
+
−		// derive the JDBC SQL type codes from the types[] names once
+
−		JdbcSQLTypes = new int[types.length];
+
−		for (int i = 0; i < types.length; i++) {
+
−			int javaSQLtype = MonetDriver.getJdbcSQLType(types[i]);
+
−			if (javaSQLtype == Types.CLOB) {
+
−				if (connection.mapClobAsVarChar())
+
−					javaSQLtype = Types.VARCHAR;
+
−			} else
+
−			if (javaSQLtype == Types.BLOB) {
+
−				if (connection.mapBlobAsVarBinary())
+
−					javaSQLtype = Types.VARBINARY;
+
−			}
+
−			JdbcSQLTypes[i] = javaSQLtype;
+
−		}
+
−
+
−		// initialize structures for storing columns info on nullability and autoincrement
+
−		array_size = colCount + 1;  // add 1 as in JDBC columns start from 1 (array from 0).
+
−		_is_queried = new boolean[array_size];
+
−		_is_fetched = new boolean[array_size];
+
−		_isNullable = new int[array_size];
+
−		_isAutoincrement = new boolean[array_size];
+
−		nextUpperbound = array_size;
+
−	}
+
−
+
−	/**
+
−	 * Alternative constructor backed by the given connection and metadata arrays.
+
−	 * It is used by MonetPreparedStatement.
+
−	 *
+
−	 * @param connection the parent connection
+
−	 * @param colcount the number of result columns, it can be zero !!
+
−	 * @param schemas the schema names
+
−	 * @param tables the table names
+
−	 * @param columns the column names
+
−	 * @param types the MonetDB type names
+
−	 * @param jdbcTypes the JDBC SQL type codes
+
−	 * @param lengths the maximum display length for each column
+
−	 * @param precisions the precision for each column
+
−	 * @param scales the scale for each column
+
−	 * @throws IllegalArgumentException if called with null for one of the arguments
+
−	 */
+
−	MonetResultSetMetaData(
+
−		final MonetConnection connection,
+
−		final int colcount,
+
−		final String[] schemas,
+
−		final String[] tables,
+
−		final String[] columns,
+
−		final String[] types,
+
−		final int[] jdbcTypes,
+
−		final int[] lengths,
+
−		final int[] precisions,
+
−		final int[] scales)
+
−		throws IllegalArgumentException
+
−	{
+
−		if (connection == null) {
+
−			throw new IllegalArgumentException("Connection may not be null!");
+
−		}
+
−		if (schemas == null) {
+
−			throw new IllegalArgumentException("Schemas may not be null!");
+
−		}
+
−		if (tables == null) {
+
−			throw new IllegalArgumentException("Tables may not be null!");
+
−		}
+
−		if (columns == null) {
+
−			throw new IllegalArgumentException("Columns may not be null!");
+
−		}
+
−		if (types == null) {
+
−			throw new IllegalArgumentException("MonetDB Types may not be null!");
+
−		}
+
−		if (jdbcTypes == null) {
+
−			throw new IllegalArgumentException("JDBC Types may not be null!");
+
−		}
+
−		if (lengths == null) {
+
−			throw new IllegalArgumentException("Lengths may not be null!");
+
−		}
+
−		if (precisions == null) {
+
−			throw new IllegalArgumentException("Precisions may not be null!");
+
−		}
+
−		if (scales == null) {
+
−			throw new IllegalArgumentException("Scales may not be null!");
+
−		}
+
−		if (columns.length != tables.length || columns.length != types.length ) {
+
−			throw new IllegalArgumentException("Inconsistent Header metadata");
+
−		}
+
−		this.conn = connection;
+
−		this.colCount = colcount;
+
−		this.schemas = schemas;
+
−		this.tables = tables;
+
−		this.columns = columns;
+
−		this.lengths = lengths;
+
−		this.types = types;
+
−		this.JdbcSQLTypes = jdbcTypes;
+
−		this.precisions = precisions;
+
−		this.scales = scales;
+
−
+
−		// initialize structures for storing columns info on nullability and autoincrement
+
−		array_size = colCount + 1;  // add 1 as in JDBC columns start from 1 (array from 0).
+
−		_is_queried = new boolean[array_size];
+
−		_is_fetched = new boolean[array_size];
+
−		_isNullable = new int[array_size];
+
−		_isAutoincrement = new boolean[array_size];
+
−		nextUpperbound = array_size;
+
−	}
+
−
+
−	/**
+
−	 * Returns the number of columns in this ResultSet object.
+
−	 *
+
−	 * @return the number of columns
+
−	 */
+
−	@Override
+
−	public int getColumnCount() {
+
−		// for debug: System.out.println("In rsmd.getColumnCount() = " + colCount + ". this rsmd object = " + this.toString());
+
−		return colCount;
+
−	}
+
−
+
−	/**
+
−	 * Indicates whether the designated column is automatically numbered.
+
−	 *
+
−	 * This method is currently very expensive for BIGINT,
+
−	 * INTEGER, SMALLINT and TINYINT result column types
+
−	 * as it needs to retrieve the information from the
+
−	 * database using an SQL meta data query.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return true if so; false otherwise
+
−	 * @throws SQLException if there is no such column or a database access error occurs
+
−	 */
+
−	@Override
+
−	public boolean isAutoIncrement(final int column) throws SQLException {
+
−		// only few integer types can be auto incrementable in MonetDB
+
−		// see: https://www.monetdb.org/Documentation/SQLReference/DataTypes/SerialDatatypes
+
−		switch (getColumnType(column)) {
+
−			case Types.BIGINT:
+
−			case Types.INTEGER:
+
−			case Types.SMALLINT:
+
−			case Types.TINYINT:
+
−				try {
+
−					if (_is_fetched[column] != true) {
+
−						fetchColumnInfo(column);
+
−					}
+
−					return _isAutoincrement[column];
+
−				} catch (IndexOutOfBoundsException e) {
+
−					throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−				}
+
−		}
+
−
+
−		return false;
+
−	}
+
−
+
−	/**
+
−	 * Indicates whether a column's case matters.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return true for all character string columns else false
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public boolean isCaseSensitive(final int column) throws SQLException {
+
−		switch (getColumnType(column)) {
+
−			case Types.CHAR:
+
−		/*	case Types.LONGVARCHAR: // MonetDB doesn't use type LONGVARCHAR */
+
−			case Types.CLOB:
+
−				return true;
+
−			case Types.VARCHAR:
+
−				try {
+
−					final String monettype = types[column - 1];
+
−					// data of type inet or uuid is not case sensitive
+
−					if ("inet".equals(monettype)
+
−					 || "uuid".equals(monettype))
+
−						return false;
+
−				} catch (IndexOutOfBoundsException e) {
+
−					throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−				}
+
−				return true;
+
−		}
+
−
+
−		return false;
+
−	}
+
−
+
−	/**
+
−	 * Indicates whether the designated column can be used in a
+
−	 * where clause.
+
−	 *
+
−	 * Returning true for all here, even for CLOB, BLOB.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return true
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public boolean isSearchable(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		return true;
+
−	}
+
−
+
−	/**
+
−	 * Indicates whether the designated column is a cash value.
+
−	 * From the MonetDB database perspective it is by definition
+
−	 * unknown whether the value is a currency, because there are
+
−	 * no currency datatypes such as MONEY.  With this knowledge
+
−	 * we can always return false here.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return false
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public boolean isCurrency(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		return false;
+
−	}
+
−
+
−	/**
+
−	 * Indicates the nullability of values in the designated column.
+
−	 *
+
−	 * This method is currently very expensive as it needs to
+
−	 * retrieve the information from the database using an SQL
+
−	 * meta data query.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return the nullability status of the given column; one of
+
−	 *	columnNoNulls, columnNullable or columnNullableUnknown
+
−	 * @throws SQLException if there is no such column or a database access error occurs
+
−	 */
+
−	@Override
+
−	public int isNullable(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		try {
+
−			if (_is_fetched[column] != true) {
+
−				fetchColumnInfo(column);
+
−			}
+
−			return _isNullable[column];
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Indicates whether values in the designated column are signed
+
−	 * numbers.
+
−	 * Within MonetDB all numeric types (except oid and ptr) are signed.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return true if so; false otherwise
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public boolean isSigned(final int column) throws SQLException {
+
−		// we can hardcode this, based on the column type
+
−		switch (getColumnType(column)) {
+
−			case Types.TINYINT:
+
−			case Types.SMALLINT:
+
−			case Types.INTEGER:
+
−			case Types.REAL:
+
−			case Types.FLOAT:
+
−			case Types.DOUBLE:
+
−			case Types.DECIMAL:
+
−			case Types.NUMERIC:
+
−			case Types.DATE:	// year can be negative
+
−			case Types.TIMESTAMP:	// year can be negative
+
−			case Types.TIMESTAMP_WITH_TIMEZONE:
+
−				return true;
+
−			case Types.BIGINT:
+
−				try {
+
−					final String monettype = types[column - 1];
+
−					// data of type oid or ptr is not signed
+
−					if ("oid".equals(monettype)
+
−					 || "ptr".equals(monettype))
+
−						return false;
+
−				} catch (IndexOutOfBoundsException e) {
+
−					throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−				}
+
−				return true;
+
−			default:
+
−				return false;
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Indicates the designated column's normal maximum width in
+
−	 * characters.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return the normal maximum number of characters allowed as the
+
−	 *         width of the designated column
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public int getColumnDisplaySize(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		try {
+
−			// Special handling for interval types
+
−			final String monettype = types[column - 1];
+
−			if (monettype != null && monettype.endsWith("_interval")) {
+
−				/* for interval types, precisions[] contains the interval subtype code */
+
−				int prec = -1;
+
− 				if (precisions != null) {
+
−					prec = precisions[column - 1];
+
−				}
+
−				switch (prec) {
+
−					case 1: return 4;	// interval year
+
−					case 2: return 6;	// interval year to month
+
−					case 3: return 6;	// interval month
+
−					case 4: return 9;	// interval day
+
−					case 5: return 11;	// interval day to hour
+
−					case 6: return 13;	// interval day to minute
+
−					case 7: return 15;	// interval day to second
+
−					case 8: return 11;	// interval hour
+
−					case 9: return 13;	// interval hour to minute
+
−					case 10: return 15;	// interval hour to second
+
−					case 11: return 13;	// interval minute
+
−					case 12: return 15;	// interval minute to second
+
−					case 13: return 15;	// interval second
+
−					default:
+
−					{	// fall back to the 3 available monettype names
+
−						if ("sec_interval".equals(monettype))
+
−							return 15;
+
−						if ("day_interval".equals(monettype))
+
−							return 9;
+
−						if ("month_interval".equals(monettype))
+
−							return 6;
+
−					}
+
−				}
+
−			}
+
−			final int len = lengths[column - 1];
+
−			if (len == 0) {
+
−				// in case of inet it always has 0 as length. we need to correct it.
+
−				if ("inet".equals(monettype)) {
+
−					return 18;	// 128.127.126.125/24
+
−				}
+
−			}
+
−			return len;
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Gets the designated column's suggested title for use in
+
−	 * printouts and displays. The suggested title is usually
+
−	 * specified by the SQL AS clause. If a SQL AS is not specified,
+
−	 * the value returned from getColumnLabel will be the same as
+
−	 * the value returned by the getColumnName method.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return the suggested column title
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public String getColumnLabel(final int column) throws SQLException {
+
−		return getColumnName(column);
+
−	}
+
−
+
−	/**
+
−	 * Gets the designated column's name
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return the column name
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public String getColumnName(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		try {
+
−			return columns[column - 1];
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Gets the designated column's table's catalog name.
+
−	 * MonetDB does not support the catalog naming concept as in: catalog.schema.table naming scheme
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return null or the name of the catalog for the table in which the given
+
−	 *         column appears or "" if not applicable
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public String getCatalogName(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		return null;	// MonetDB does NOT support catalog qualifiers
+
−
+
−	}
+
−
+
−	/**
+
−	 * Get the designated column's schema name.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return schema name or "" if not applicable
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public String getSchemaName(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		try {
+
−			return schemas[column - 1];
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Gets the designated column's table name.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return table name or "" if not applicable
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public String getTableName(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		try {
+
−			return tables[column - 1];
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Retrieves the designated column's SQL type.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return SQL type from java.sql.Types
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public int getColumnType(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		try {
+
−			return JdbcSQLTypes[column - 1];
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Retrieves the designated column's database-specific type name.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return type name used by the database. If the column type is a
+
−	 *         user-defined type, then a fully-qualified type name is
+
−	 *         returned.
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public String getColumnTypeName(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		try {
+
−			final String monettype = types[column - 1];
+
−			if (monettype != null && monettype.endsWith("_interval")) {
+
−				/* convert the interval type names to valid SQL data type names,
+
−				 * such that generic applications can use them in create table statements
+
−				 */
+
−				/* for interval types, precisions[] contains the interval subtype code */
+
−				int prec = -1;
+
− 				if (precisions != null) {
+
−					prec = precisions[column - 1];
+
−				}
+
−				switch (prec) {
+
−					case 1: return "interval year";
+
−					case 2: return "interval year to month";
+
−					case 3: return "interval month";
+
−					case 4: return "interval day";
+
−					case 5: return "interval day to hour";
+
−					case 6: return "interval day to minute";
+
−					case 7: return "interval day to second";
+
−					case 8: return "interval hour";
+
−					case 9: return "interval hour to minute";
+
−					case 10: return "interval hour to second";
+
−					case 11: return "interval minute";
+
−					case 12: return "interval minute to second";
+
−					case 13: return "interval second";
+
−					default:	// when no precisions array was available
+
−					{	// fall back to the 3 available monettype names
+
−						if ("day_interval".equals(monettype))
+
−							return "interval day";
+
−						if ("month_interval".equals(monettype))
+
−							return "interval month";
+
−						if ("sec_interval".equals(monettype))
+
−							return "interval second";
+
−					}
+
−				}
+
−			}
+
−			return monettype;
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Get the designated column's specified column size.
+
−	 * For numeric data, this is the maximum precision.
+
−	 * For character data, this is the length in characters.
+
−	 * For datetime datatypes, this is the length in characters
+
−	 * of the String representation (assuming the maximum
+
−	 * allowed precision of the fractional seconds component).
+
−	 * For binary data, this is the length in bytes.
+
−	 * For the ROWID datatype, this is the length in bytes.
+
−	 * 0 is returned for data types where the column size is not applicable.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return maximum precision or length in characters
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public int getPrecision(final int column) throws SQLException {
+
−		switch (getColumnType(column)) {
+
−			case Types.BIGINT:
+
−				return 19;
+
−			case Types.INTEGER:
+
−				return 10;
+
−			case Types.SMALLINT:
+
−				return 5;
+
−			case Types.TINYINT:
+
−				return 3;
+
−			case Types.REAL:
+
−				return 7;
+
−			case Types.FLOAT:
+
−			case Types.DOUBLE:
+
−				return 15;
+
−			case Types.DECIMAL:
+
−			case Types.NUMERIC:
+
−				// these data types have a variable precision (max precision is 38)
+
−				if (precisions != null) {
+
−					try {
+
−						// Special handling for: day_interval and sec_interval as they are
+
−						// mapped to Types.NUMERIC and Types.DECIMAL types (see MonetDriver typeMap)
+
−						final String monettype = types[column - 1];
+
−						if (monettype != null && monettype.endsWith("_interval")) {
+
−							/* for interval types, precisions[] contains the interval subtype code */
+
−							switch (precisions[column - 1]) {
+
−								case 1: return 4;	// interval year
+
−								case 2: return 6;	// interval year to month
+
−								case 3: return 6;	// interval month
+
−								case 4: return 9;	// interval day
+
−								case 5: return 11;	// interval day to hour
+
−								case 6: return 13;	// interval day to minute
+
−								case 7: return 15;	// interval day to second
+
−								case 8: return 11;	// interval hour
+
−								case 9: return 13;	// interval hour to minute
+
−								case 10: return 15;	// interval hour to second
+
−								case 11: return 13;	// interval minute
+
−								case 12: return 15;	// interval minute to second
+
−								case 13: return 15;	// interval second
+
−								default:
+
−								{	// fall back to the 3 available monettype names
+
−									if ("sec_interval".equals(monettype))
+
−										return 15;
+
−									if ("day_interval".equals(monettype))
+
−										return 9;
+
−									if ("month_interval".equals(monettype))
+
−										return 6;
+
−								}
+
−							}
+
−						}
+
−						return precisions[column - 1];
+
−					} catch (IndexOutOfBoundsException e) {
+
−						throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−					}
+
−				}
+
−				return 18;
+
−			case Types.CHAR:
+
−			case Types.VARCHAR:
+
−		/*	case Types.LONGVARCHAR: // MonetDB doesn't use type LONGVARCHAR */
+
−			case Types.CLOB:
+
−				// these data types have a variable length
+
−				if (precisions != null) {
+
−					try {
+
−						int prec = precisions[column - 1];
+
−						if (prec <= 0) {
+
−							// apparently no positive precision or max length could be fetched
+
−							// use columnDisplaySize() value as fallback
+
−							prec = getColumnDisplaySize(column);
+
−							precisions[column - 1] = prec;
+
−						}
+
−						return prec;
+
−					} catch (IndexOutOfBoundsException e) {
+
−						throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−					}
+
−				}
+
−				// apparently no precisions array is available
+
−				// use columnDisplaySize() value as alternative
+
−				return getColumnDisplaySize(column);
+
−			case Types.BINARY:
+
−			case Types.VARBINARY:
+
−		/*	case Types.LONGVARBINARY: // MonetDB doesn't use type LONGVARBINARY */
+
−			case Types.BLOB:
+
−				// these data types have a variable length
+
−				if (precisions != null) {
+
−					try {
+
−						int prec = precisions[column - 1];
+
−						if (prec <= 0) {
+
−							// apparently no positive precision or max length could be fetched
+
−							// use columnDisplaySize() value as fallback
+
−							// It expect number of bytes, not number of hex chars
+
−							prec = (getColumnDisplaySize(column) / 2) +1;
+
−							precisions[column - 1] = prec;
+
−						}
+
−						return prec;
+
−					} catch (IndexOutOfBoundsException e) {
+
−						throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−					}
+
−				}
+
−				// apparently no precisions array is available
+
−				// use columnDisplaySize() value as alternative
+
−				// It expect number of bytes, not number of hex chars
+
−				return (getColumnDisplaySize(column) / 2) +1;
+
−			case Types.DATE:
+
−				return 10;	// 2020-10-08
+
−			case Types.TIME:
+
−				return 15;	// 21:51:34.399753
+
−			case Types.TIME_WITH_TIMEZONE:
+
−				return 21;	// 21:51:34.399753+02:00
+
−			case Types.TIMESTAMP:
+
−				return 26;	// 2020-10-08 21:51:34.399753
+
−			case Types.TIMESTAMP_WITH_TIMEZONE:
+
−				return 32;	// 2020-10-08 21:51:34.399753+02:00
+
−			case Types.BOOLEAN:
+
−				return 1;
+
−			default:
+
−				// All other types should return 0
+
−				return 0;
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Gets the designated column's number of digits to right of
+
−	 * the decimal point.
+
−	 * 0 is returned for data types where the scale is not applicable.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return scale
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public int getScale(final int column) throws SQLException {
+
−		switch (getColumnType(column)) {
+
−			case Types.DECIMAL:
+
−			case Types.NUMERIC:
+
−				// these data types may have a variable scale, max scale is 38
+
−				try {
+
−					// Special handling for: day_interval and sec_interval as they are
+
−					// mapped to Types.NUMERIC and Types.DECIMAL types (see MonetDriver typeMap)
+
−					// They appear to have a fixed scale (tested against Oct2020)
+
−					final String monettype = types[column - 1];
+
−					if ("day_interval".equals(monettype))
+
−						return 0;
+
−					if ("sec_interval".equals(monettype))
+
−						return 3;
+
−
+
−					if (scales != null) {
+
−						return scales[column - 1];
+
−					}
+
−					return 0;
+
−				} catch (IndexOutOfBoundsException e) {
+
−					throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−				}
+
−			case Types.TIME:
+
−			case Types.TIME_WITH_TIMEZONE:
+
−			case Types.TIMESTAMP:
+
−			case Types.TIMESTAMP_WITH_TIMEZONE:
+
−				try {
+
−					if (scales != null) {
+
−						return scales[column - 1];
+
−					}
+
−					// support microseconds, so scale 6
+
−					return 6;	// 21:51:34.399753
+
−				} catch (IndexOutOfBoundsException e) {
+
−					throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−				}
+
−
+
−			// All other types should return 0
+
−		//	case Types.BIGINT:
+
−		//	case Types.INTEGER:
+
−		//	case Types.SMALLINT:
+
−		//	case Types.TINYINT:
+
−		//	case Types.REAL:
+
−		//	case Types.FLOAT:
+
−		//	case Types.DOUBLE:
+
−		//	case Types.CHAR:
+
−		//	case Types.VARCHAR:
+
−		//	case Types.LONGVARCHAR: // MonetDB doesn't use type LONGVARCHAR
+
−		//	case Types.CLOB:
+
−		//	case Types.BINARY:
+
−		//	case Types.VARBINARY:
+
−		//	case Types.LONGVARBINARY: // MonetDB doesn't use type LONGVARBINARY
+
−		//	case Types.BLOB:
+
−		//	case Types.DATE:
+
−		//	case Types.BOOLEAN:
+
−			default:
+
−				return 0;
+
−		}
+
−	}
+
−
+
−	/**
+
−	 * Indicates whether the designated column is definitely not
+
−	 * writable.  MonetDB does not support cursor updates, so
+
−	 * nothing is writable.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return true if so; false otherwise
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public boolean isReadOnly(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		return true;
+
−	}
+
−
+
−	/**
+
−	 * Indicates whether it is possible for a write on the
+
−	 * designated column to succeed.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return true if so; false otherwise
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public boolean isWritable(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		return false;
+
−	}
+
−
+
−	/**
+
−	 * Indicates whether a write on the designated column will
+
−	 * definitely succeed.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return true if so; false otherwise
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public boolean isDefinitelyWritable(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		return false;
+
−	}
+
−
+
−	/**
+
−	 * Returns the fully-qualified name of the Java class whose instances
+
−	 * are manufactured if the method ResultSet.getObject is called to
+
−	 * retrieve a value from the column.
+
−	 * ResultSet.getObject may return a subclass of the class returned by
+
−	 * this method.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @return the fully-qualified name of the class in the Java programming
+
−	 *	language that would be used by the method ResultSet.getObject
+
−	 *	to retrieve the value in the specified column. This is the
+
−	 *	class name used for custom mapping.
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	@Override
+
−	public String getColumnClassName(final int column) throws SQLException {
+
−		checkColumnIndexValidity(column);
+
−		try {
+
−			final String MonetDBType = types[column - 1];
+
−			Class<?> type = null;
+
−			if (conn != null) {
+
−				final java.util.Map<String,Class<?>> map = conn.getTypeMap();
+
−				if (map != null && map.containsKey(MonetDBType)) {
+
−					type = (Class)map.get(MonetDBType);
+
−				}
+
−			}
+
−			if (type == null) {
+
−				// fallback to the standard SQL type Class mappings
+
−				type = MonetDriver.getClassForType(JdbcSQLTypes[column - 1]);
+
−			}
+
−			if (type != null) {
+
−				return type.getCanonicalName();
+
−			}
+
−			throw new SQLException("column type mapping null: " + MonetDBType, "M0M03");
+
−		} catch (IndexOutOfBoundsException e) {
+
−			throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−		}
+
−	}
+
−
+
−
+
−	/**
+
−	 * A private utility method to check validity of column index number
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @throws java.sql.SQLDataException when invalid column index number
+
−	 */
+
−	private final void checkColumnIndexValidity(final int column) throws java.sql.SQLDataException {
+
−		if (column < 1 || column > colCount)
+
−			throw MonetResultSet.newSQLInvalidColumnIndexException(column);
+
−	}
+
−
+
−	/**
+
−	 * A private method to fetch the isNullable and isAutoincrement values
+
−	 * combined for a specific column.
+
−	 * The fetched values are stored in the array caches.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @throws SQLException if there is no such column
+
−	 */
+
−	private final void fetchColumnInfo(final int column) throws SQLException {
+
−		// for debug: System.out.println("fetchColumnInfo(" + column + ")");
+
−		checkColumnIndexValidity(column);
+
−		if (_is_fetched[column] != true) {
+
−			// fetch column info for multiple columns combined in one go
+
−			fetchManyColumnsInfo(column);
+
−		}
+
−		if (_is_fetched[column])
+
−			return;
+
−
+
−		// apparently no data could be fetched for this resultset column, fall back to defaults
+
−		_isNullable[column] = columnNullableUnknown;
+
−		_isAutoincrement[column] = false;
+
−	}
+
−
+
−	/**
+
−	 * A private method to fetch the isNullable and isAutoincrement values
+
−	 * for many fully qualified columns combined in one SQL query to reduce the number of queries sent.
+
−	 * As fetching this meta information from the server per column is costly we combine the querying of
+
−	 * the isNullable and isAutoincrement values and cache it in internal arrays.
+
−	 * We also do this for many columns combined in one query to reduce
+
−	 * the number of queries needed for fetching this metadata for all resultset columns.
+
−	 * Many generic JDBC database tools (e.g. SQuirreL, DBeaver) request this meta data for each
+
−	 * column of each resultset, so these optimisations reduces the number of meta data queries significantly.
+
−	 *
+
−	 * @param column the first column is 1, the second is 2, ...
+
−	 * @throws SQLException if a database access error occurs
+
−	 */
+
−	private final void fetchManyColumnsInfo(final int column) throws SQLException {
+
−		// for debug: System.out.println("fetchManyColumnsInfo(" + column + ")");
+
−
+
−		// Most queries have less than 80 resultset columns
+
−		// So 80 is a good balance between speedup (up to 79x) and size of generated query sent to server
+
−		final int MAX_COLUMNS_PER_QUERY = 80;
+
−
+
−		// Determine the optimal startcol to make use of fetching up to 80 columns in one query.
+
−		int startcol = column;
+
−		if ((startcol > 1) && (startcol + MAX_COLUMNS_PER_QUERY >= nextUpperbound)) {
+
−			// we can fetch info from more columns in one query if we start with a lower startcol
+
−			startcol = nextUpperbound - MAX_COLUMNS_PER_QUERY;
+
−			if (startcol < 1) {
+
−				startcol = 1;
+
−			} else
+
−			if (startcol > column) {
+
−				startcol = column;
+
−			}
+
−			nextUpperbound = startcol;	// next time this nextUpperbound value will be used
+
−			// for debug: System.out.println("fetchManyColumnsInfo(" + column + ")" + (startcol != column ? " changed into startcol: " + startcol : "") + " nextUpperbound: " + nextUpperbound);
+
−		}
+
−
+
−		final StringBuilder query = new StringBuilder(410 + (java.lang.Math.min(MAX_COLUMNS_PER_QUERY, colCount) * 150));
+
−		/* next SQL query is a simplified version of query in MonetDatabaseMetaData.getColumns(), to fetch only the needed attributes of a column */
+
−		query.append("SELECT " +
+
−			"s.\"name\" AS schnm, " +
+
−			"t.\"name\" AS tblnm, " +
+
−			"c.\"name\" AS colnm, " +
+
−			"cast(CASE c.\"null\" WHEN true THEN " + ResultSetMetaData.columnNullable +
+
−				" WHEN false THEN " + ResultSetMetaData.columnNoNulls +
+
−				" ELSE " + ResultSetMetaData.columnNullableUnknown +
+
−				" END AS int) AS nullable, " +
+
−			"cast(CASE WHEN c.\"default\" IS NOT NULL AND c.\"default\" LIKE 'next value for %' THEN true ELSE false END AS boolean) AS isautoincrement " +
+
−		"FROM \"sys\".\"columns\" c " +
+
−		"JOIN \"sys\".\"tables\" t ON c.\"table_id\" = t.\"id\" " +
+
−		"JOIN \"sys\".\"schemas\" s ON t.\"schema_id\" = s.\"id\" " +
+
−		"WHERE ");
+
−
+
−		/* combine the conditions for multiple (up to 80) columns into the WHERE-clause */
+
−		String schName = null;
+
−		String tblName = null;
+
−		String colName = null;
+
−		int queriedcolcount = 0;
+
−		for (int col = startcol; col < array_size && queriedcolcount < MAX_COLUMNS_PER_QUERY; col++) {
+
−			if (_is_fetched[col] != true) {
+
−				if (_is_queried[col] != true) {
+
−					_isNullable[col] = columnNullableUnknown;
+
−					_isAutoincrement[col] = false;
+
−					schName = getSchemaName(col);
+
−					if (schName != null && !schName.isEmpty()) {
+
−						tblName = getTableName(col);
+
−						if (tblName != null && !tblName.isEmpty()) {
+
−							colName = getColumnName(col);
+
−							if (colName != null && !colName.isEmpty()) {
+
−								if (queriedcolcount > 0)
+
−									query.append(" OR ");
+
−								query.append("(s.\"name\" = ").append(MonetWrapper.sq(schName));
+
−								query.append(" AND t.\"name\" = ").append(MonetWrapper.sq(tblName));
+
−								query.append(" AND c.\"name\" = ").append(MonetWrapper.sq(colName));
+
−								query.append(")");
+
−								_is_queried[col] = true;	// flag it
+
−								queriedcolcount++;
+
−							}
+
−						}
+
−					}
+
−					if (_is_queried[col] != true) {
+
−						// make sure we do not try to query it again next time as it is not queryable
+
−						_is_fetched[col] = true;
+
−					}
+
−				}
+
−			}
+
−		}
+
−
+
−		if (queriedcolcount == 0)
+
−			return;
+
−
+
−		// execute query to get information on queriedcolcount (or less) columns.
+
−		final java.sql.Statement stmt = conn.createStatement();
+
−		if (stmt != null) {
+
−			// for debug: System.out.println("SQL (len " + query.length() + "): " + query.toString());
+
−			final java.sql.ResultSet rs = stmt.executeQuery(query.toString());
+
−			if (rs != null) {
+
−				String rsSchema = null;
+
−				String rsTable = null;
+
−				String rsColumn = null;
+
−				while (rs.next()) {
+
−					rsSchema = rs.getString(1);	// col 1 is schnm
+
−					rsTable = rs.getString(2);	// col 2 is tblnm
+
−					rsColumn = rs.getString(3);	// col 3 is colnm
+
−					// find the matching schema.table.column entry in the array
+
−					for (int col = 1; col < array_size; col++) {
+
−						if (_is_fetched[col] != true && _is_queried[col]) {
+
−							colName = getColumnName(col);
+
−							if (colName != null && colName.equals(rsColumn)) {
+
−								tblName = getTableName(col);
+
−								if (tblName != null && tblName.equals(rsTable)) {
+
−									schName = getSchemaName(col);
+
−									if (schName != null && schName.equals(rsSchema)) {
+
−										// found matching entry
+
−										// for debug: System.out.println("Found match at [" + col + "] for " + schName + "." + tblName + "." + colName);
+
−										_isNullable[col] = rs.getInt(4);	// col 4 is nullable (or "NULLABLE")
+
−										_isAutoincrement[col] = rs.getBoolean(5); // col 5 is isautoincrement (or "IS_AUTOINCREMENT")
+
−										_is_fetched[col] = true;
+
−										queriedcolcount--;
+
−										// we found the match, exit the for-loop
+
−										col = array_size;
+
−									}
+
−								}
+
−							}
+
−						}
+
−					}
+
−				}
+
−				rs.close();
+
−			}
+
−			stmt.close();
+
−		}
+
−
+
−		if (queriedcolcount != 0) {
+
−			// not all queried columns have resulted in a returned data row.
+
−			// make sure we do not match those columns again next run
+
−			for (int col = startcol; col < array_size; col++) {
+
−				if (_is_fetched[col] != true && _is_queried[col]) {
+
−					_is_fetched[col] = true;
+
−					// for debug: System.out.println("Found NO match at [" + col + "] for " + getSchemaName(col) + "." + getTableName(col) + "." + getColumnName(col));
+
−				}
+
−			}
+
−		}
+
−	}
+
−}
+
−