apewer-dotnet/Apewer.Source/Externals/MySql.Data-6.10.9/MySqlClient/SchemaProvider.cs

#if MYSQL_6_10

// Copyright (c) 2004, 2019, Oracle and/or its affiliates. All rights reserved.
//
// MySQL Connector/NET is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most 
// MySQL Connectors. There are special exceptions to the terms and 
// conditions of the GPLv2 as it is applied to this software, see the 
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify 
// it under the terms of the GNU General Public License as published 
// by the Free Software Foundation; version 2 of the License.
//
// 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., 
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

using System;
using System.Globalization;
using System.IO;
using System.Reflection;
using System.Text;
using System.Text.RegularExpressions;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using Externals.MySql.Data.Common;
using Externals.MySql.Data.Types;

namespace Externals.MySql.Data.MySqlClient
{
    internal class SchemaProvider
    {
        protected MySqlConnection connection;
        public static string MetaCollection = "MetaDataCollections";

        public SchemaProvider(MySqlConnection connectionToUse)
        {
            connection = connectionToUse;
        }

        public virtual MySqlSchemaCollection GetSchema(string collection, String[] restrictions)
        {
            if (connection.State != ConnectionState.Open)
                throw new MySqlException("GetSchema can only be called on an open connection.");

            collection = StringUtility.ToUpperInvariant(collection);

            MySqlSchemaCollection c = GetSchemaInternal(collection, restrictions);

            if (c == null)
                throw new ArgumentException("Invalid collection name");
            return c;
        }

        public virtual MySqlSchemaCollection GetDatabases(string[] restrictions)
        {
            Regex regex = null;
            int caseSetting = Int32.Parse(connection.driver.Property("lower_case_table_names"), CultureInfo.InvariantCulture);

            string sql = "SHOW DATABASES";

            // if lower_case_table_names is zero, then case lookup should be sensitive
            // so we can use LIKE to do the matching.
            if (caseSetting == 0)
            {
                if (restrictions != null && restrictions.Length >= 1)
                    sql = sql + " LIKE '" + restrictions[0] + "'";
            }

            MySqlSchemaCollection c = QueryCollection("Databases", sql);

            if (caseSetting != 0 && restrictions != null && restrictions.Length >= 1 && restrictions[0] != null)
                regex = new Regex(restrictions[0], RegexOptions.IgnoreCase);

            MySqlSchemaCollection c2 = new MySqlSchemaCollection("Databases");
            c2.AddColumn("CATALOG_NAME", typeof(string));
            c2.AddColumn("SCHEMA_NAME", typeof(string));

            foreach (MySqlSchemaRow row in c.Rows)
            {
                if (regex != null && !regex.Match(row[0].ToString()).Success) continue;
                MySqlSchemaRow newRow = c2.AddRow();
                newRow[1] = row[0];
            }
            return c2;
        }

        public virtual MySqlSchemaCollection GetTables(string[] restrictions)
        {
            MySqlSchemaCollection c = new MySqlSchemaCollection("Tables");
            c.AddColumn("TABLE_CATALOG", typeof(string));
            c.AddColumn("TABLE_SCHEMA", typeof(string));
            c.AddColumn("TABLE_NAME", typeof(string));
            c.AddColumn("TABLE_TYPE", typeof(string));
            c.AddColumn("ENGINE", typeof(string));
            c.AddColumn("VERSION", typeof(ulong));
            c.AddColumn("ROW_FORMAT", typeof(string));
            c.AddColumn("TABLE_ROWS", typeof(ulong));
            c.AddColumn("AVG_ROW_LENGTH", typeof(ulong));
            c.AddColumn("DATA_LENGTH", typeof(ulong));
            c.AddColumn("MAX_DATA_LENGTH", typeof(ulong));
            c.AddColumn("INDEX_LENGTH", typeof(ulong));
            c.AddColumn("DATA_FREE", typeof(ulong));
            c.AddColumn("AUTO_INCREMENT", typeof(ulong));
            c.AddColumn("CREATE_TIME", typeof(DateTime));
            c.AddColumn("UPDATE_TIME", typeof(DateTime));
            c.AddColumn("CHECK_TIME", typeof(DateTime));
            c.AddColumn("TABLE_COLLATION", typeof(string));
            c.AddColumn("CHECKSUM", typeof(ulong));
            c.AddColumn("CREATE_OPTIONS", typeof(string));
            c.AddColumn("TABLE_COMMENT", typeof(string));

            // we have to new up a new restriction array here since
            // GetDatabases takes the database in the first slot
            string[] dbRestriction = new string[4];
            if (restrictions != null && restrictions.Length >= 2)
                dbRestriction[0] = restrictions[1];
            MySqlSchemaCollection databases = GetDatabases(dbRestriction);

            if (restrictions != null)
                Array.Copy(restrictions, dbRestriction,
                       Math.Min(dbRestriction.Length, restrictions.Length));

            foreach (MySqlSchemaRow row in databases.Rows)
            {
                dbRestriction[1] = row["SCHEMA_NAME"].ToString();
                FindTables(c, dbRestriction);
            }
            return c;
        }

        protected void QuoteDefaultValues(MySqlSchemaCollection schemaCollection)
        {
            if (schemaCollection == null) return;
            if (!schemaCollection.ContainsColumn("COLUMN_DEFAULT")) return;

            foreach (MySqlSchemaRow row in schemaCollection.Rows)
            {
                object defaultValue = row["COLUMN_DEFAULT"];
                if (MetaData.IsTextType(row["DATA_TYPE"].ToString()))
                    row["COLUMN_DEFAULT"] = String.Format("{0}", defaultValue);
            }
        }

        public virtual MySqlSchemaCollection GetColumns(string[] restrictions)
        {
            MySqlSchemaCollection c = new MySqlSchemaCollection("Columns");
            c.AddColumn("TABLE_CATALOG", typeof(string));
            c.AddColumn("TABLE_SCHEMA", typeof(string));
            c.AddColumn("TABLE_NAME", typeof(string));
            c.AddColumn("COLUMN_NAME", typeof(string));
            c.AddColumn("ORDINAL_POSITION", typeof(ulong));
            c.AddColumn("COLUMN_DEFAULT", typeof(string));
            c.AddColumn("IS_NULLABLE", typeof(string));
            c.AddColumn("DATA_TYPE", typeof(string));
            c.AddColumn("CHARACTER_MAXIMUM_LENGTH", typeof(ulong));
            c.AddColumn("CHARACTER_OCTET_LENGTH", typeof(ulong));
            c.AddColumn("NUMERIC_PRECISION", typeof(ulong));
            c.AddColumn("NUMERIC_SCALE", typeof(ulong));
            c.AddColumn("CHARACTER_SET_NAME", typeof(string));
            c.AddColumn("COLLATION_NAME", typeof(string));
            c.AddColumn("COLUMN_TYPE", typeof(string));
            c.AddColumn("COLUMN_KEY", typeof(string));
            c.AddColumn("EXTRA", typeof(string));
            c.AddColumn("PRIVILEGES", typeof(string));
            c.AddColumn("COLUMN_COMMENT", typeof(string));
            c.AddColumn("GENERATION_EXPRESSION", typeof(string));

            // we don't allow restricting on table type here
            string columnName = null;
            if (restrictions != null && restrictions.Length == 4)
            {
                columnName = restrictions[3];
                restrictions[3] = null;
            }
            MySqlSchemaCollection tables = GetTables(restrictions);

            foreach (MySqlSchemaRow row in tables.Rows)
                LoadTableColumns(c, row["TABLE_SCHEMA"].ToString(),
                         row["TABLE_NAME"].ToString(), columnName);

            QuoteDefaultValues(c);
            return c;
        }

        private void LoadTableColumns(MySqlSchemaCollection schemaCollection, string schema,
                        string tableName, string columnRestriction)
        {
            string sql = String.Format("SHOW FULL COLUMNS FROM `{0}`.`{1}`",
                           schema, tableName);
            MySqlCommand cmd = new MySqlCommand(sql, connection);

            int pos = 1;
            using (MySqlDataReader reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    string colName = reader.GetString(0);
                    if (columnRestriction != null && colName != columnRestriction)
                        continue;
                    MySqlSchemaRow row = schemaCollection.AddRow();
                    row["TABLE_CATALOG"] = DBNull.Value;
                    row["TABLE_SCHEMA"] = schema;
                    row["TABLE_NAME"] = tableName;
                    row["COLUMN_NAME"] = colName;
                    row["ORDINAL_POSITION"] = pos++;
                    row["COLUMN_DEFAULT"] = reader.GetValue(5);
                    row["IS_NULLABLE"] = reader.GetString(3);
                    row["DATA_TYPE"] = reader.GetString(1);
                    row["CHARACTER_MAXIMUM_LENGTH"] = DBNull.Value;
                    row["CHARACTER_OCTET_LENGTH"] = DBNull.Value;
                    row["NUMERIC_PRECISION"] = DBNull.Value;
                    row["NUMERIC_SCALE"] = DBNull.Value;
                    row["CHARACTER_SET_NAME"] = reader.GetValue(2);
                    row["COLLATION_NAME"] = row["CHARACTER_SET_NAME"];
                    row["COLUMN_TYPE"] = reader.GetString(1);
                    row["COLUMN_KEY"] = reader.GetString(4);
                    row["EXTRA"] = reader.GetString(6);
                    row["PRIVILEGES"] = reader.GetString(7);
                    row["COLUMN_COMMENT"] = reader.GetString(8);
                    row["GENERATION_EXPRESION"] = reader.GetString(6).Contains("VIRTUAL") ? reader.GetString(9) : string.Empty;
                    ParseColumnRow(row);
                }
            }
        }

        private static void ParseColumnRow(MySqlSchemaRow row)
        {
            // first parse the character set name
            string charset = row["CHARACTER_SET_NAME"].ToString();
            int index = charset.IndexOf('_');
            if (index != -1)
                row["CHARACTER_SET_NAME"] = charset.Substring(0, index);

            // now parse the data type
            string dataType = row["DATA_TYPE"].ToString();
            index = dataType.IndexOf('(');
            if (index == -1)
                return;
            row["DATA_TYPE"] = dataType.Substring(0, index);
            int stop = dataType.IndexOf(')', index);
            string dataLen = dataType.Substring(index + 1, stop - (index + 1));
            string lowerType = row["DATA_TYPE"].ToString().ToLower();
            if (lowerType == "char" || lowerType == "varchar")
                row["CHARACTER_MAXIMUM_LENGTH"] = dataLen;
            else if (lowerType == "real" || lowerType == "decimal")
            {
                string[] lenparts = dataLen.Split(new char[] { ',' });
                row["NUMERIC_PRECISION"] = lenparts[0];
                if (lenparts.Length == 2)
                    row["NUMERIC_SCALE"] = lenparts[1];
            }
        }

        public virtual MySqlSchemaCollection GetIndexes(string[] restrictions)
        {
            MySqlSchemaCollection dt = new MySqlSchemaCollection("Indexes");
            dt.AddColumn("INDEX_CATALOG", typeof(string));
            dt.AddColumn("INDEX_SCHEMA", typeof(string));
            dt.AddColumn("INDEX_NAME", typeof(string));
            dt.AddColumn("TABLE_NAME", typeof(string));
            dt.AddColumn("UNIQUE", typeof(bool));
            dt.AddColumn("PRIMARY", typeof(bool));
            dt.AddColumn("TYPE", typeof(string));
            dt.AddColumn("COMMENT", typeof(string));

            // Get the list of tables first
            int max = restrictions?.Length ?? 4;
            string[] tableRestrictions = new string[Math.Max(max, 4)];
            restrictions?.CopyTo(tableRestrictions, 0);
            tableRestrictions[3] = "BASE TABLE";
            MySqlSchemaCollection tables = GetTables(tableRestrictions);

            foreach (MySqlSchemaRow table in tables.Rows)
            {
                string sql = String.Format("SHOW INDEX FROM `{0}`.`{1}`",
                  MySqlHelper.DoubleQuoteString((string)table["TABLE_SCHEMA"]),
                  MySqlHelper.DoubleQuoteString((string)table["TABLE_NAME"]));
                MySqlSchemaCollection indexes = QueryCollection("indexes", sql);

                foreach (MySqlSchemaRow index in indexes.Rows)
                {
                    if (1 != (connection.driver.Version.isAtLeast(8, 0, 1) ?
                      (uint)index["SEQ_IN_INDEX"] :
                      (long)index["SEQ_IN_INDEX"]))
                        continue;
                    if (restrictions != null && restrictions.Length == 4 &&
                      restrictions[3] != null &&
                      !index["KEY_NAME"].Equals(restrictions[3])) continue;
                    MySqlSchemaRow row = dt.AddRow();
                    row["INDEX_CATALOG"] = null;
                    row["INDEX_SCHEMA"] = table["TABLE_SCHEMA"];
                    row["INDEX_NAME"] = index["KEY_NAME"];
                    row["TABLE_NAME"] = index["TABLE"];
                    row["UNIQUE"] = connection.driver.Version.isAtLeast(8, 0, 1) ?
                      Convert.ToInt64(index["NON_UNIQUE"]) == 0 :
                      (long)index["NON_UNIQUE"] == 0;
                    row["PRIMARY"] = index["KEY_NAME"].Equals("PRIMARY");
                    row["TYPE"] = index["INDEX_TYPE"];
                    row["COMMENT"] = index["COMMENT"];
                }
            }

            return dt;
        }

        public virtual MySqlSchemaCollection GetIndexColumns(string[] restrictions)
        {
            MySqlSchemaCollection dt = new MySqlSchemaCollection("IndexColumns");
            dt.AddColumn("INDEX_CATALOG", typeof(string));
            dt.AddColumn("INDEX_SCHEMA", typeof(string));
            dt.AddColumn("INDEX_NAME", typeof(string));
            dt.AddColumn("TABLE_NAME", typeof(string));
            dt.AddColumn("COLUMN_NAME", typeof(string));
            dt.AddColumn("ORDINAL_POSITION", typeof(int));
            dt.AddColumn("SORT_ORDER", typeof(string));

            int max = restrictions == null ? 4 : restrictions.Length;
            string[] tableRestrictions = new string[Math.Max(max, 4)];
            if (restrictions != null)
                restrictions.CopyTo(tableRestrictions, 0);
            tableRestrictions[3] = "BASE TABLE";
            MySqlSchemaCollection tables = GetTables(tableRestrictions);

            foreach (MySqlSchemaRow table in tables.Rows)
            {
                string sql = String.Format("SHOW INDEX FROM `{0}`.`{1}`",
                               table["TABLE_SCHEMA"], table["TABLE_NAME"]);
                MySqlCommand cmd = new MySqlCommand(sql, connection);
                using (MySqlDataReader reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        string key_name = GetString(reader, reader.GetOrdinal("KEY_NAME"));
                        string col_name = GetString(reader, reader.GetOrdinal("COLUMN_NAME"));

                        if (restrictions != null)
                        {
                            if (restrictions.Length >= 4 && restrictions[3] != null &&
                              key_name != restrictions[3]) continue;
                            if (restrictions.Length >= 5 && restrictions[4] != null &&
                              col_name != restrictions[4]) continue;
                        }
                        MySqlSchemaRow row = dt.AddRow();
                        row["INDEX_CATALOG"] = null;
                        row["INDEX_SCHEMA"] = table["TABLE_SCHEMA"];
                        row["INDEX_NAME"] = key_name;
                        row["TABLE_NAME"] = GetString(reader, reader.GetOrdinal("TABLE"));
                        row["COLUMN_NAME"] = col_name;
                        row["ORDINAL_POSITION"] = reader.GetValue(reader.GetOrdinal("SEQ_IN_INDEX"));
                        row["SORT_ORDER"] = reader.GetString("COLLATION");
                    }
                }
            }

            return dt;
        }

        public virtual MySqlSchemaCollection GetForeignKeys(string[] restrictions)
        {
            MySqlSchemaCollection dt = new MySqlSchemaCollection("Foreign Keys");
            dt.AddColumn("CONSTRAINT_CATALOG", typeof(string));
            dt.AddColumn("CONSTRAINT_SCHEMA", typeof(string));
            dt.AddColumn("CONSTRAINT_NAME", typeof(string));
            dt.AddColumn("TABLE_CATALOG", typeof(string));
            dt.AddColumn("TABLE_SCHEMA", typeof(string));
            dt.AddColumn("TABLE_NAME", typeof(string));
            dt.AddColumn("MATCH_OPTION", typeof(string));
            dt.AddColumn("UPDATE_RULE", typeof(string));
            dt.AddColumn("DELETE_RULE", typeof(string));
            dt.AddColumn("REFERENCED_TABLE_CATALOG", typeof(string));
            dt.AddColumn("REFERENCED_TABLE_SCHEMA", typeof(string));
            dt.AddColumn("REFERENCED_TABLE_NAME", typeof(string));

            // first we use our restrictions to get a list of tables that should be
            // consulted.  We save the keyname restriction since GetTables doesn't 
            // understand that.
            string keyName = null;
            if (restrictions != null && restrictions.Length >= 4)
            {
                keyName = restrictions[3];
                restrictions[3] = null;
            }

            MySqlSchemaCollection tables = GetTables(restrictions);

            // now for each table retrieved, we call our helper function to
            // parse it's foreign keys
            foreach (MySqlSchemaRow table in tables.Rows)
                GetForeignKeysOnTable(dt, table, keyName, false);

            return dt;
        }

        public virtual MySqlSchemaCollection GetForeignKeyColumns(string[] restrictions)
        {
            MySqlSchemaCollection dt = new MySqlSchemaCollection("Foreign Keys");
            dt.AddColumn("CONSTRAINT_CATALOG", typeof(string));
            dt.AddColumn("CONSTRAINT_SCHEMA", typeof(string));
            dt.AddColumn("CONSTRAINT_NAME", typeof(string));
            dt.AddColumn("TABLE_CATALOG", typeof(string));
            dt.AddColumn("TABLE_SCHEMA", typeof(string));
            dt.AddColumn("TABLE_NAME", typeof(string));
            dt.AddColumn("COLUMN_NAME", typeof(string));
            dt.AddColumn("ORDINAL_POSITION", typeof(int));
            dt.AddColumn("REFERENCED_TABLE_CATALOG", typeof(string));
            dt.AddColumn("REFERENCED_TABLE_SCHEMA", typeof(string));
            dt.AddColumn("REFERENCED_TABLE_NAME", typeof(string));
            dt.AddColumn("REFERENCED_COLUMN_NAME", typeof(string));

            // first we use our restrictions to get a list of tables that should be
            // consulted.  We save the keyname restriction since GetTables doesn't 
            // understand that.
            string keyName = null;
            if (restrictions != null && restrictions.Length >= 4)
            {
                keyName = restrictions[3];
                restrictions[3] = null;
            }

            MySqlSchemaCollection tables = GetTables(restrictions);

            // now for each table retrieved, we call our helper function to
            // parse it's foreign keys
            foreach (MySqlSchemaRow table in tables.Rows)
                GetForeignKeysOnTable(dt, table, keyName, true);
            return dt;
        }


        private string GetSqlMode()
        {
            MySqlCommand cmd = new MySqlCommand("SELECT @@SQL_MODE", connection);
            return cmd.ExecuteScalar().ToString();
        }

        #region Foreign Key routines

        /// <summary>
        /// GetForeignKeysOnTable retrieves the foreign keys on the given table.
        /// Since MySQL supports foreign keys on versions prior to 5.0, we can't  use
        /// information schema.  MySQL also does not include any type of SHOW command
        /// for foreign keys so we have to resort to use SHOW CREATE TABLE and parsing
        /// the output.
        /// </summary>
        /// <param name="fkTable">The table to store the key info in.</param>
        /// <param name="tableToParse">The table to get the foeign key info for.</param>
        /// <param name="filterName">Only get foreign keys that match this name.</param>
        /// <param name="includeColumns">Should column information be included in the table.</param>
        private void GetForeignKeysOnTable(MySqlSchemaCollection fkTable, MySqlSchemaRow tableToParse,
                           string filterName, bool includeColumns)
        {
            string sqlMode = GetSqlMode();

            if (filterName != null)
                filterName = StringUtility.ToLowerInvariant(filterName);

            string sql = string.Format("SHOW CREATE TABLE `{0}`.`{1}`",
                           tableToParse["TABLE_SCHEMA"], tableToParse["TABLE_NAME"]);
            string lowerBody = null, body = null;
            MySqlCommand cmd = new MySqlCommand(sql, connection);
            using (MySqlDataReader reader = cmd.ExecuteReader())
            {
                reader.Read();
                body = reader.GetString(1);
                lowerBody = StringUtility.ToLowerInvariant(body);
            }

            MySqlTokenizer tokenizer = new MySqlTokenizer(lowerBody);
            tokenizer.AnsiQuotes = sqlMode.IndexOf("ANSI_QUOTES") != -1;
            tokenizer.BackslashEscapes = sqlMode.IndexOf("NO_BACKSLASH_ESCAPES") != -1;

            while (true)
            {
                string token = tokenizer.NextToken();
                // look for a starting contraint
                while (token != null && (token != "constraint" || tokenizer.Quoted))
                    token = tokenizer.NextToken();
                if (token == null) break;

                ParseConstraint(fkTable, tableToParse, tokenizer, includeColumns);
            }
        }

        private static void ParseConstraint(MySqlSchemaCollection fkTable, MySqlSchemaRow table,
          MySqlTokenizer tokenizer, bool includeColumns)
        {
            string name = tokenizer.NextToken();
            MySqlSchemaRow row = fkTable.AddRow();

            // make sure this constraint is a FK
            string token = tokenizer.NextToken();
            if (token != "foreign" || tokenizer.Quoted)
                return;
            tokenizer.NextToken(); // read off the 'KEY' symbol
            tokenizer.NextToken(); // read off the '(' symbol

            row["CONSTRAINT_CATALOG"] = table["TABLE_CATALOG"];
            row["CONSTRAINT_SCHEMA"] = table["TABLE_SCHEMA"];
            row["TABLE_CATALOG"] = table["TABLE_CATALOG"];
            row["TABLE_SCHEMA"] = table["TABLE_SCHEMA"];
            row["TABLE_NAME"] = table["TABLE_NAME"];
            row["REFERENCED_TABLE_CATALOG"] = null;
            row["CONSTRAINT_NAME"] = name.Trim(new char[] { '\'', '`' });

            List<string> srcColumns = includeColumns ? ParseColumns(tokenizer) : null;

            // now look for the references section
            while (token != "references" || tokenizer.Quoted)
                token = tokenizer.NextToken();
            string target1 = tokenizer.NextToken();
            string target2 = tokenizer.NextToken();
            if (target2.StartsWith(".", StringComparison.Ordinal))
            {
                row["REFERENCED_TABLE_SCHEMA"] = target1;
                row["REFERENCED_TABLE_NAME"] = target2.Substring(1).Trim(new char[] { '\'', '`' });
                tokenizer.NextToken();  // read off the '('
            }
            else
            {
                row["REFERENCED_TABLE_SCHEMA"] = table["TABLE_SCHEMA"];
                row["REFERENCED_TABLE_NAME"] = target1.Substring(1).Trim(new char[] { '\'', '`' }); ;
            }

            // if we are supposed to include columns, read the target columns
            List<string> targetColumns = includeColumns ? ParseColumns(tokenizer) : null;

            if (includeColumns)
                ProcessColumns(fkTable, row, srcColumns, targetColumns);
            else
                fkTable.Rows.Add(row);
        }

        private static List<string> ParseColumns(MySqlTokenizer tokenizer)
        {
            List<string> sc = new List<string>();
            string token = tokenizer.NextToken();
            while (token != ")")
            {
                if (token != ",")
                    sc.Add(token);
                token = tokenizer.NextToken();
            }
            return sc;
        }

        private static void ProcessColumns(MySqlSchemaCollection fkTable, MySqlSchemaRow row, List<string> srcColumns, List<string> targetColumns)
        {
            for (int i = 0; i < srcColumns.Count; i++)
            {
                MySqlSchemaRow newRow = fkTable.AddRow();
                row.CopyRow(newRow);
                newRow["COLUMN_NAME"] = srcColumns[i];
                newRow["ORDINAL_POSITION"] = i;
                newRow["REFERENCED_COLUMN_NAME"] = targetColumns[i];
                fkTable.Rows.Add(newRow);
            }
        }

        #endregion

        public virtual MySqlSchemaCollection GetUsers(string[] restrictions)
        {
            StringBuilder sb = new StringBuilder("SELECT Host, User FROM mysql.user");
            if (restrictions != null && restrictions.Length > 0)
                sb.AppendFormat(CultureInfo.InvariantCulture, " WHERE User LIKE '{0}'", restrictions[0]);

            MySqlSchemaCollection c = QueryCollection("Users", sb.ToString());
            c.Columns[0].Name = "HOST";
            c.Columns[1].Name = "USERNAME";

            return c;
        }

        public virtual MySqlSchemaCollection GetProcedures(string[] restrictions)
        {
            MySqlSchemaCollection dt = new MySqlSchemaCollection("Procedures");
            dt.AddColumn("SPECIFIC_NAME", typeof(string));
            dt.AddColumn("ROUTINE_CATALOG", typeof(string));
            dt.AddColumn("ROUTINE_SCHEMA", typeof(string));
            dt.AddColumn("ROUTINE_NAME", typeof(string));
            dt.AddColumn("ROUTINE_TYPE", typeof(string));
            dt.AddColumn("DTD_IDENTIFIER", typeof(string));
            dt.AddColumn("ROUTINE_BODY", typeof(string));
            dt.AddColumn("ROUTINE_DEFINITION", typeof(string));
            dt.AddColumn("EXTERNAL_NAME", typeof(string));
            dt.AddColumn("EXTERNAL_LANGUAGE", typeof(string));
            dt.AddColumn("PARAMETER_STYLE", typeof(string));
            dt.AddColumn("IS_DETERMINISTIC", typeof(string));
            dt.AddColumn("SQL_DATA_ACCESS", typeof(string));
            dt.AddColumn("SQL_PATH", typeof(string));
            dt.AddColumn("SECURITY_TYPE", typeof(string));
            dt.AddColumn("CREATED", typeof(DateTime));
            dt.AddColumn("LAST_ALTERED", typeof(DateTime));
            dt.AddColumn("SQL_MODE", typeof(string));
            dt.AddColumn("ROUTINE_COMMENT", typeof(string));
            dt.AddColumn("DEFINER", typeof(string));

            StringBuilder sql = null;

            if (connection.driver.Version.isAtLeast(8, 0, 1))
            {
                sql = new StringBuilder("SELECT * FROM information_schema.routines WHERE 1=1");
                if (restrictions != null)
                {
                    if (restrictions.Length >= 2 && restrictions[1] != null)
                        sql.AppendFormat(CultureInfo.InvariantCulture,
                          " AND routine_schema LIKE '{0}'", restrictions[1]);
                    if (restrictions.Length >= 3 && restrictions[2] != null)
                        sql.AppendFormat(CultureInfo.InvariantCulture,
                          " AND routine_name LIKE '{0}'", restrictions[2]);
                    if (restrictions.Length >= 4 && restrictions[3] != null)
                        sql.AppendFormat(CultureInfo.InvariantCulture,
                          " AND routine_type LIKE '{0}'", restrictions[3]);
                }

                MySqlCommand cmd = new MySqlCommand(sql.ToString(), connection);
                using (MySqlDataReader reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        MySqlSchemaRow row = dt.AddRow();
                        row["SPECIFIC_NAME"] = reader.GetString("specific_name");
                        row["ROUTINE_CATALOG"] = DBNull.Value;
                        row["ROUTINE_SCHEMA"] = reader.GetString("routine_schema");
                        row["ROUTINE_NAME"] = reader.GetString("routine_name");
                        string routineType = reader.GetString("routine_type");
                        row["ROUTINE_TYPE"] = routineType;
                        row["DTD_IDENTIFIER"] = StringUtility.ToLowerInvariant(routineType) == "function" ?
                          (object)reader.GetString("DTD_IDENTIFIER") : DBNull.Value;
                        row["ROUTINE_BODY"] = "SQL";
                        row["ROUTINE_DEFINITION"] = reader.GetString("routine_definition");
                        row["EXTERNAL_NAME"] = DBNull.Value;
                        row["EXTERNAL_LANGUAGE"] = DBNull.Value;
                        row["PARAMETER_STYLE"] = "SQL";
                        row["IS_DETERMINISTIC"] = reader.GetString("is_deterministic");
                        row["SQL_DATA_ACCESS"] = reader.GetString("sql_data_access");
                        row["SQL_PATH"] = DBNull.Value;
                        row["SECURITY_TYPE"] = reader.GetString("security_type");
                        row["CREATED"] = reader.GetDateTime("created");
                        row["LAST_ALTERED"] = reader.GetDateTime("last_altered");
                        row["SQL_MODE"] = reader.GetString("sql_mode");
                        row["ROUTINE_COMMENT"] = reader.GetString("routine_comment");
                        row["DEFINER"] = reader.GetString("definer");
                    }
                }
            }
            else
            {
                sql = new StringBuilder("SELECT * FROM mysql.proc WHERE 1=1");
                if (restrictions != null)
                {
                    if (restrictions.Length >= 2 && restrictions[1] != null)
                        sql.AppendFormat(CultureInfo.InvariantCulture,
                          " AND db LIKE '{0}'", restrictions[1]);
                    if (restrictions.Length >= 3 && restrictions[2] != null)
                        sql.AppendFormat(CultureInfo.InvariantCulture,
                          " AND name LIKE '{0}'", restrictions[2]);
                    if (restrictions.Length >= 4 && restrictions[3] != null)
                        sql.AppendFormat(CultureInfo.InvariantCulture,
                          " AND type LIKE '{0}'", restrictions[3]);
                }

                MySqlCommand cmd = new MySqlCommand(sql.ToString(), connection);
                using (MySqlDataReader reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        MySqlSchemaRow row = dt.AddRow();
                        row["SPECIFIC_NAME"] = reader.GetString("specific_name");
                        row["ROUTINE_CATALOG"] = DBNull.Value;
                        row["ROUTINE_SCHEMA"] = reader.GetString("db");
                        row["ROUTINE_NAME"] = reader.GetString("name");
                        string routineType = reader.GetString("type");
                        row["ROUTINE_TYPE"] = routineType;
                        row["DTD_IDENTIFIER"] = StringUtility.ToLowerInvariant(routineType) == "function" ?
                          (object)reader.GetString("returns") : DBNull.Value;
                        row["ROUTINE_BODY"] = "SQL";
                        row["ROUTINE_DEFINITION"] = reader.GetString("body");
                        row["EXTERNAL_NAME"] = DBNull.Value;
                        row["EXTERNAL_LANGUAGE"] = DBNull.Value;
                        row["PARAMETER_STYLE"] = "SQL";
                        row["IS_DETERMINISTIC"] = reader.GetString("is_deterministic");
                        row["SQL_DATA_ACCESS"] = reader.GetString("sql_data_access");
                        row["SQL_PATH"] = DBNull.Value;
                        row["SECURITY_TYPE"] = reader.GetString("security_type");
                        row["CREATED"] = reader.GetDateTime("created");
                        row["LAST_ALTERED"] = reader.GetDateTime("modified");
                        row["SQL_MODE"] = reader.GetString("sql_mode");
                        row["ROUTINE_COMMENT"] = reader.GetString("comment");
                        row["DEFINER"] = reader.GetString("definer");
                    }
                }
            }

            return dt;
        }

        protected virtual MySqlSchemaCollection GetCollections()
        {
            object[][] collections = {
          new object[] {"MetaDataCollections", 0, 0},
          new object[] {"DataSourceInformation", 0, 0},
          new object[] {"DataTypes", 0, 0},
          new object[] {"Restrictions", 0, 0},
          new object[] {"ReservedWords", 0, 0},
          new object[] {"Databases", 1, 1},
          new object[] {"Tables", 4, 2},
          new object[] {"Columns", 4, 4},
          new object[] {"Users", 1, 1},
          new object[] {"Foreign Keys", 4, 3},
          new object[] {"IndexColumns", 5, 4},
          new object[] {"Indexes", 4, 3},
          new object[] {"Foreign Key Columns", 4, 3},
          new object[] {"UDF", 1, 1}
        };

            MySqlSchemaCollection dt = new MySqlSchemaCollection("MetaDataCollections");
            dt.AddColumn("CollectionName", typeof(string));
            dt.AddColumn("NumberOfRestrictions", typeof(int));
            dt.AddColumn("NumberOfIdentifierParts", typeof(int));

            FillTable(dt, collections);

            return dt;
        }

#if !NETSTANDARD1_3
        private MySqlSchemaCollection GetDataSourceInformation()
        {
            MySqlSchemaCollection dt = new MySqlSchemaCollection("DataSourceInformation");
            dt.AddColumn("CompositeIdentifierSeparatorPattern", typeof(string));
            dt.AddColumn("DataSourceProductName", typeof(string));
            dt.AddColumn("DataSourceProductVersion", typeof(string));
            dt.AddColumn("DataSourceProductVersionNormalized", typeof(string));
            dt.AddColumn("GroupByBehavior", typeof(GroupByBehavior));
            dt.AddColumn("IdentifierPattern", typeof(string));
            dt.AddColumn("IdentifierCase", typeof(IdentifierCase));
            dt.AddColumn("OrderByColumnsInSelect", typeof(bool));
            dt.AddColumn("ParameterMarkerFormat", typeof(string));
            dt.AddColumn("ParameterMarkerPattern", typeof(string));
            dt.AddColumn("ParameterNameMaxLength", typeof(int));
            dt.AddColumn("ParameterNamePattern", typeof(string));
            dt.AddColumn("QuotedIdentifierPattern", typeof(string));
            dt.AddColumn("QuotedIdentifierCase", typeof(IdentifierCase));
            dt.AddColumn("StatementSeparatorPattern", typeof(string));
            dt.AddColumn("StringLiteralPattern", typeof(string));
            dt.AddColumn("SupportedJoinOperators", typeof(SupportedJoinOperators));

            DBVersion v = connection.driver.Version;
            string ver = $"{v.Major:0}.{v.Minor:0}.{v.Build:0}";

            MySqlSchemaRow row = dt.AddRow();
            row["CompositeIdentifierSeparatorPattern"] = "\\.";
            row["DataSourceProductName"] = "MySQL";
            row["DataSourceProductVersion"] = connection.ServerVersion;
            row["DataSourceProductVersionNormalized"] = ver;
            row["GroupByBehavior"] = GroupByBehavior.Unrelated;
            row["IdentifierPattern"] =
              @"(^\`\p{Lo}\p{Lu}\p{Ll}_@#][\p{Lo}\p{Lu}\p{Ll}\p{Nd}@$#_]*$)|(^\`[^\`\0]|\`\`+\`$)|(^\"" + [^\""\0]|\""\""+\""$)";
            row["IdentifierCase"] = IdentifierCase.Insensitive;
            row["OrderByColumnsInSelect"] = false;
            row["ParameterMarkerFormat"] = "{0}";
            row["ParameterMarkerPattern"] = "(@[A-Za-z0-9_$#]*)";
            row["ParameterNameMaxLength"] = 128;
            row["ParameterNamePattern"] =
              @"^[\p{Lo}\p{Lu}\p{Ll}\p{Lm}_@#][\p{Lo}\p{Lu}\p{Ll}\p{Lm}\p{Nd}\uff3f_@#\$]*(?=\s+|$)";
            row["QuotedIdentifierPattern"] = @"(([^\`]|\`\`)*)";
            row["QuotedIdentifierCase"] = IdentifierCase.Sensitive;
            row["StatementSeparatorPattern"] = ";";
            row["StringLiteralPattern"] = "'(([^']|'')*)'";
            row["SupportedJoinOperators"] = 15;
            dt.Rows.Add(row);

            return dt;
        }
#endif

        private static MySqlSchemaCollection GetDataTypes()
        {
            MySqlSchemaCollection dt = new MySqlSchemaCollection("DataTypes");
            dt.AddColumn("TypeName", typeof(string));
            dt.AddColumn("ProviderDbType", typeof(int));
            dt.AddColumn("ColumnSize", typeof(long));
            dt.AddColumn("CreateFormat", typeof(string));
            dt.AddColumn("CreateParameters", typeof(string));
            dt.AddColumn("DataType", typeof(string));
            dt.AddColumn("IsAutoincrementable", typeof(bool));
            dt.AddColumn("IsBestMatch", typeof(bool));
            dt.AddColumn("IsCaseSensitive", typeof(bool));
            dt.AddColumn("IsFixedLength", typeof(bool));
            dt.AddColumn("IsFixedPrecisionScale", typeof(bool));
            dt.AddColumn("IsLong", typeof(bool));
            dt.AddColumn("IsNullable", typeof(bool));
            dt.AddColumn("IsSearchable", typeof(bool));
            dt.AddColumn("IsSearchableWithLike", typeof(bool));
            dt.AddColumn("IsUnsigned", typeof(bool));
            dt.AddColumn("MaximumScale", typeof(short));
            dt.AddColumn("MinimumScale", typeof(short));
            dt.AddColumn("IsConcurrencyType", typeof(bool));
            dt.AddColumn("IsLiteralSupported", typeof(bool));
            dt.AddColumn("LiteralPrefix", typeof(string));
            dt.AddColumn("LiteralSuffix", typeof(string));
            dt.AddColumn("NativeDataType", typeof(string));

            // have each one of the types contribute to the datatypes collection
            MySqlBit.SetDSInfo(dt);
            MySqlBinary.SetDSInfo(dt);
            MySqlDateTime.SetDSInfo(dt);
            MySqlTimeSpan.SetDSInfo(dt);
            MySqlString.SetDSInfo(dt);
            MySqlDouble.SetDSInfo(dt);
            MySqlSingle.SetDSInfo(dt);
            MySqlByte.SetDSInfo(dt);
            MySqlInt16.SetDSInfo(dt);
            MySqlInt32.SetDSInfo(dt);
            MySqlInt64.SetDSInfo(dt);
            MySqlDecimal.SetDSInfo(dt);
            MySqlUByte.SetDSInfo(dt);
            MySqlUInt16.SetDSInfo(dt);
            MySqlUInt32.SetDSInfo(dt);
            MySqlUInt64.SetDSInfo(dt);

            return dt;
        }

        protected virtual MySqlSchemaCollection GetRestrictions()
        {
            object[][] restrictions = {
          new object[] {"Users", "Name", "", 0},
          new object[] {"Databases", "Name", "", 0},
          new object[] {"Tables", "Database", "", 0},
          new object[] {"Tables", "Schema", "", 1},
          new object[] {"Tables", "Table", "", 2},
          new object[] {"Tables", "TableType", "", 3},
          new object[] {"Columns", "Database", "", 0},
          new object[] {"Columns", "Schema", "", 1},
          new object[] {"Columns", "Table", "", 2},
          new object[] {"Columns", "Column", "", 3},
          new object[] {"Indexes", "Database", "", 0},
          new object[] {"Indexes", "Schema", "", 1},
          new object[] {"Indexes", "Table", "", 2},
          new object[] {"Indexes", "Name", "", 3},
          new object[] {"IndexColumns", "Database", "", 0},
          new object[] {"IndexColumns", "Schema", "", 1},
          new object[] {"IndexColumns", "Table", "", 2},
          new object[] {"IndexColumns", "ConstraintName", "", 3},
          new object[] {"IndexColumns", "Column", "", 4},
          new object[] {"Foreign Keys", "Database", "", 0},
          new object[] {"Foreign Keys", "Schema", "", 1},
          new object[] {"Foreign Keys", "Table", "", 2},
          new object[] {"Foreign Keys", "Constraint Name", "", 3},
          new object[] {"Foreign Key Columns", "Catalog", "", 0},
          new object[] {"Foreign Key Columns", "Schema", "", 1},
          new object[] {"Foreign Key Columns", "Table", "", 2},
          new object[] {"Foreign Key Columns", "Constraint Name", "", 3},
          new object[] {"UDF", "Name", "", 0}
        };

            MySqlSchemaCollection dt = new MySqlSchemaCollection("Restrictions");
            dt.AddColumn("CollectionName", typeof(string));
            dt.AddColumn("RestrictionName", typeof(string));
            dt.AddColumn("RestrictionDefault", typeof(string));
            dt.AddColumn("RestrictionNumber", typeof(int));

            FillTable(dt, restrictions);

            return dt;
        }

        private static MySqlSchemaCollection GetReservedWords()
        {
            MySqlSchemaCollection dt = new MySqlSchemaCollection("ReservedWords");
#if !NETSTANDARD1_3
            dt.AddColumn(DbMetaDataColumnNames.ReservedWord, typeof(string));
            Stream str = Assembly.GetExecutingAssembly().GetManifestResourceStream(
              "Externals.MySql.Data.Properties.ReservedWords.txt");
#else
      dt.AddColumn("ReservedWord", typeof(string));
      Stream str = typeof(SchemaProvider).GetTypeInfo().Assembly.GetManifestResourceStream("Externals.MySql.Data.Properties.ReservedWords.txt");
#endif

            StreamReader sr = new StreamReader(str);
            string line = sr.ReadLine();
            while (line != null)
            {
                MySqlSchemaRow row = dt.AddRow();
                row[0] = line;
                line = sr.ReadLine();
            }
            sr.Dispose();

            return dt;
        }

        protected static void FillTable(MySqlSchemaCollection dt, object[][] data)
        {
            foreach (object[] dataItem in data)
            {
                MySqlSchemaRow row = dt.AddRow();
                for (int i = 0; i < dataItem.Length; i++)
                    row[i] = dataItem[i];
            }
        }

        private void FindTables(MySqlSchemaCollection schema, string[] restrictions)
        {
            StringBuilder sql = new StringBuilder();
            StringBuilder where = new StringBuilder();
            sql.AppendFormat(CultureInfo.InvariantCulture,
                     "SHOW TABLE STATUS FROM `{0}`", restrictions[1]);
            if (restrictions != null && restrictions.Length >= 3 &&
              restrictions[2] != null)
                where.AppendFormat(CultureInfo.InvariantCulture,
                           " LIKE '{0}'", restrictions[2]);
            sql.Append(where.ToString());

            string table_type = restrictions[1].ToLower() == "information_schema"
                        ?
                      "SYSTEM VIEW"
                        : "BASE TABLE";

            MySqlCommand cmd = new MySqlCommand(sql.ToString(), connection);
            using (MySqlDataReader reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    MySqlSchemaRow row = schema.AddRow();
                    row["TABLE_CATALOG"] = null;
                    row["TABLE_SCHEMA"] = restrictions[1];
                    row["TABLE_NAME"] = reader.GetString(0);
                    row["TABLE_TYPE"] = table_type;
                    row["ENGINE"] = GetString(reader, 1);
                    row["VERSION"] = reader.GetValue(2);
                    row["ROW_FORMAT"] = GetString(reader, 3);
                    row["TABLE_ROWS"] = reader.GetValue(4);
                    row["AVG_ROW_LENGTH"] = reader.GetValue(5);
                    row["DATA_LENGTH"] = reader.GetValue(6);
                    row["MAX_DATA_LENGTH"] = reader.GetValue(7);
                    row["INDEX_LENGTH"] = reader.GetValue(8);
                    row["DATA_FREE"] = reader.GetValue(9);
                    row["AUTO_INCREMENT"] = reader.GetValue(10);
                    row["CREATE_TIME"] = reader.GetValue(11);
                    row["UPDATE_TIME"] = reader.GetValue(12);
                    row["CHECK_TIME"] = reader.GetValue(13);
                    row["TABLE_COLLATION"] = GetString(reader, 14);
                    row["CHECKSUM"] = reader.GetValue(15);
                    row["CREATE_OPTIONS"] = GetString(reader, 16);
                    row["TABLE_COMMENT"] = GetString(reader, 17);
                }
            }
        }

        private static string GetString(MySqlDataReader reader, int index)
        {
            if (reader.IsDBNull(index))
                return null;
            return reader.GetString(index);
        }

        public virtual MySqlSchemaCollection GetUDF(string[] restrictions)
        {
            string sql = "SELECT name,ret,dl FROM mysql.func";
            if (restrictions?.Length >= 1 && !String.IsNullOrEmpty(restrictions[0]))
                sql += $" WHERE name LIKE '{restrictions[0]}'";

            MySqlSchemaCollection dt = new MySqlSchemaCollection("User-defined Functions");
            dt.AddColumn("NAME", typeof(string));
            dt.AddColumn("RETURN_TYPE", typeof(int));
            dt.AddColumn("LIBRARY_NAME", typeof(string));

            MySqlCommand cmd = new MySqlCommand(sql, connection);
            try
            {
                using (MySqlDataReader reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        MySqlSchemaRow row = dt.AddRow();
                        row[0] = reader.GetString(0);
                        row[1] = reader.GetInt32(1);
                        row[2] = reader.GetString(2);
                    }
                }
            }
            catch (MySqlException ex)
            {
                if (ex.Number != (int)MySqlErrorCode.TableAccessDenied)
                    throw;
                throw new MySqlException(Resources.UnableToEnumerateUDF, ex);
            }

            return dt;
        }

        protected virtual MySqlSchemaCollection GetSchemaInternal(string collection, string[] restrictions)
        {
            switch (collection)
            {
                // common collections
                case "METADATACOLLECTIONS":
                    return GetCollections();
#if !NETSTANDARD1_3
                case "DATASOURCEINFORMATION":
                    return GetDataSourceInformation();
#endif
                case "DATATYPES":
                    return GetDataTypes();
                case "RESTRICTIONS":
                    return GetRestrictions();
                case "RESERVEDWORDS":
                    return GetReservedWords();

                // collections specific to our provider
                case "USERS":
                    return GetUsers(restrictions);
                case "DATABASES":
                    return GetDatabases(restrictions);
                case "UDF":
                    return GetUDF(restrictions);
            }

            // if we have a current database and our users have
            // not specified a database, then default to the currently
            // selected one.
            if (restrictions == null)
                restrictions = new string[2];
            if (connection != null &&
              connection.Database != null &&
              connection.Database.Length > 0 &&
              restrictions.Length > 1 &&
              restrictions[1] == null)
                restrictions[1] = connection.Database;

            switch (collection)
            {
                case "TABLES":
                    return GetTables(restrictions);
                case "COLUMNS":
                    return GetColumns(restrictions);
                case "INDEXES":
                    return GetIndexes(restrictions);
                case "INDEXCOLUMNS":
                    return GetIndexColumns(restrictions);
                case "FOREIGN KEYS":
                    return GetForeignKeys(restrictions);
                case "FOREIGN KEY COLUMNS":
                    return GetForeignKeyColumns(restrictions);
            }
            return null;
        }

        internal string[] CleanRestrictions(string[] restrictionValues)
        {
            string[] restrictions = null;
            if (restrictionValues != null)
            {
                restrictions = (string[])restrictionValues.Clone();

                for (int x = 0; x < restrictions.Length; x++)
                {
                    string s = restrictions[x];
                    if (s == null) continue;
                    restrictions[x] = s.Trim('`');
                }
            }
            return restrictions;
        }

        protected MySqlSchemaCollection QueryCollection(string name, string sql)
        {
            MySqlSchemaCollection c = new MySqlSchemaCollection(name);
            MySqlCommand cmd = new MySqlCommand(sql, connection);
            MySqlDataReader reader = cmd.ExecuteReader();

            for (int i = 0; i < reader.FieldCount; i++)
                c.AddColumn(reader.GetName(i), reader.GetFieldType(i));

            using (reader)
            {
                while (reader.Read())
                {
                    MySqlSchemaRow row = c.AddRow();
                    for (int i = 0; i < reader.FieldCount; i++)
                        row[i] = reader.GetValue(i);
                }
            }
            return c;
        }
    }
}

#endif