//--------------------------------------------------------------------- // // Portions of this file copyright (c) Microsoft Corporation // and are released under the Microsoft Pulic License. See // http://archive.msdn.microsoft.com/EFSampleProvider/Project/License.aspx // or License.txt for details. // All rights reserved. // //--------------------------------------------------------------------- #if USE_ENTITY_FRAMEWORK_6 namespace System.Data.SQLite.EF6 #else namespace System.Data.SQLite.Linq #endif { using System; using System.Collections.Generic; #if USE_ENTITY_FRAMEWORK_6 using System.Data.Entity.Core.Metadata.Edm; #else using System.Data.Metadata.Edm; #endif /// /// /// This class represents an extent/nested select statement, /// or a column. /// /// The important fields are Name, Type and NewName. /// NewName starts off the same as Name, and is then modified as necessary. /// /// /// The rest are used by special symbols. /// e.g. NeedsRenaming is used by columns to indicate that a new name must /// be picked for the column in the second phase of translation. /// /// IsUnnest is used by symbols for a collection expression used as a from clause. /// This allows to add the column list /// after the alias. /// /// class Symbol : ISqlFragment { private Dictionary columns = new Dictionary(StringComparer.CurrentCultureIgnoreCase); internal Dictionary Columns { get { return columns; } } private bool needsRenaming = false; internal bool NeedsRenaming { get { return needsRenaming; } set { needsRenaming = value; } } bool isUnnest = false; internal bool IsUnnest { get { return isUnnest; } set { isUnnest = value; } } string name; public string Name { get { return name; } } string newName; public string NewName { get { return newName; } set { newName = value; } } private TypeUsage type; internal TypeUsage Type { get { return type; } set { type = value; } } public Symbol(string name, TypeUsage type) { this.name = name; this.newName = name; this.Type = type; } #region ISqlFragment Members /// /// Write this symbol out as a string for sql. This is just /// the new name of the symbol (which could be the same as the old name). /// /// We rename columns here if necessary. /// /// /// public void WriteSql(SqlWriter writer, SqlGenerator sqlGenerator) { if (this.NeedsRenaming) { string newName; int i = sqlGenerator.AllColumnNames[this.NewName]; do { ++i; newName = this.Name + i.ToString(System.Globalization.CultureInfo.InvariantCulture); } while (sqlGenerator.AllColumnNames.ContainsKey(newName)); sqlGenerator.AllColumnNames[this.NewName] = i; // Prevent it from being renamed repeatedly. this.NeedsRenaming = false; this.NewName = newName; // Add this column name to list of known names so that there are no subsequent // collisions sqlGenerator.AllColumnNames[newName] = 0; } writer.Write(SqlGenerator.QuoteIdentifier(this.NewName)); } #endregion } }