UniqueConstraint.cs source code in C# .NET

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Code:

/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / System / Data / UniqueConstraint.cs / 2 / UniqueConstraint.cs

                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
// [....]
// [....] 
//----------------------------------------------------------------------------- 

namespace System.Data { 
    using System;
    using System.Diagnostics;
    using System.ComponentModel;
 
    /// 
    ///     
    ///       Represents a restriction on a set of columns in which all values must be unique. 
    ///    
    ///  
    [
    DefaultProperty("ConstraintName"),
    Editor("Microsoft.VSDesigner.Data.Design.UniqueConstraintEditor, " + AssemblyRef.MicrosoftVSDesigner, "System.Drawing.Design.UITypeEditor, " + AssemblyRef.SystemDrawing),
    ] 
#if WINFSInternalOnly
    internal 
#else 
    public
#endif 
    class UniqueConstraint : Constraint {
        private DataKey key;
        private Index _constraintIndex;
        internal bool bPrimaryKey = false; 

        // Design time serialization 
        internal string constraintName = null; 
        internal string[] columnNames = null;
 
        /// 
        /// Initializes a new instance of the  with the specified name and
        /// .
        ///  
        public UniqueConstraint(String name, DataColumn column) {
            DataColumn[] columns = new DataColumn[1]; 
            columns[0] = column; 
            Create(name, columns);
        } 

        /// 
        /// Initializes a new instance of the  with the specified .
        ///  
        public UniqueConstraint(DataColumn column) {
            DataColumn[] columns = new DataColumn[1]; 
            columns[0] = column; 
            Create(null, columns);
        } 

        /// 
        /// Initializes a new instance of the  with the specified name and array
        ///    of  objects. 
        /// 
        public UniqueConstraint(String name, DataColumn[] columns) { 
            Create(name, columns); 
        }
 
        /// 
        ///    
        ///       Initializes a new instance of the  with the given array of 
        ///       objects. 
        ///    
        ///  
        public UniqueConstraint(DataColumn[] columns) { 
            Create(null, columns);
        } 

        // Construct design time object
        /// 
        ///    [To be supplied.] 
        /// 
        [Browsable(false)] 
        public UniqueConstraint(String name, string[] columnNames, bool isPrimaryKey) { 
            this.constraintName = name;
            this.columnNames = columnNames; 
            this.bPrimaryKey = isPrimaryKey;
        }

        ///  
        /// Initializes a new instance of the  with the specified name and
        /// . 
        ///  
        public UniqueConstraint(String name, DataColumn column, bool isPrimaryKey) {
            DataColumn[] columns = new DataColumn[1]; 
            columns[0] = column;
            this.bPrimaryKey = isPrimaryKey;
            Create(name, columns);
        } 

        ///  
        /// Initializes a new instance of the  with the specified . 
        /// 
        public UniqueConstraint(DataColumn column, bool isPrimaryKey) { 
            DataColumn[] columns = new DataColumn[1];
            columns[0] = column;
            this.bPrimaryKey = isPrimaryKey;
            Create(null, columns); 
        }
 
        ///  
        /// Initializes a new instance of the  with the specified name and array
        ///    of  objects. 
        /// 
        public UniqueConstraint(String name, DataColumn[] columns, bool isPrimaryKey) {
            this.bPrimaryKey = isPrimaryKey;
            Create(name, columns); 
        }
 
        ///  
        ///    
        ///       Initializes a new instance of the  with the given array of  
        ///       objects.
        ///    
        /// 
        public UniqueConstraint(DataColumn[] columns, bool isPrimaryKey) { 
            this.bPrimaryKey = isPrimaryKey;
            Create(null, columns); 
        } 

        // design time serialization only 
        internal string[] ColumnNames {
            get {
                return key.GetColumnNames();
            } 
        }
 
        internal Index ConstraintIndex { 
            get {
                Debug.Assert(null != _constraintIndex, "null UniqueConstraint index"); 
                Debug.Assert(_constraintIndex == key.GetSortIndex(), "different unique index");
                return _constraintIndex;
            }
        } 

        internal void ConstraintIndexClear() { 
            if (null != _constraintIndex) { 
                _constraintIndex.RemoveRef();
                _constraintIndex = null; 
            }
        }

        internal void ConstraintIndexInitialize() { 
            //Debug.Assert(null == _constraintIndex, "non-null UniqueConstraint index");
            if (null == _constraintIndex) { 
                _constraintIndex = key.GetSortIndex(); 
                _constraintIndex.AddRef();
            } 
            Debug.Assert(_constraintIndex == key.GetSortIndex(), "unexpected sort index");
        }

        internal override void CheckState() { 
           NonVirtualCheckState();
        } 
 
        private  void NonVirtualCheckState() {
            key.CheckState(); 
        }

        internal override void CheckCanAddToCollection(ConstraintCollection constraints) {
        } 

        internal override bool CanBeRemovedFromCollection(ConstraintCollection constraints, bool fThrowException) { 
            if (this.Equals(constraints.Table.primaryKey)) { 
                Debug.Assert(constraints.Table.primaryKey == this, "If the primary key and this are 'Equal', they should also be '=='");
                if (!fThrowException) 
                    return false;
                else
                    throw ExceptionBuilder.RemovePrimaryKey(constraints.Table);
            } 
            for (ParentForeignKeyConstraintEnumerator cs = new ParentForeignKeyConstraintEnumerator(Table.DataSet, Table); cs.GetNext();) {
                ForeignKeyConstraint constraint = cs.GetForeignKeyConstraint(); 
                if (!key.ColumnsEqual(constraint.ParentKey)) 
                    continue;
 
                if (!fThrowException)
                    return false;
                else
                    throw ExceptionBuilder.NeededForForeignKeyConstraint(this, constraint); 
            }
 
            return true; 
        }
 
        internal override bool CanEnableConstraint() {
            if (Table.EnforceConstraints)
                return ConstraintIndex.CheckUnique();
 
            return true;
        } 
 
        internal override bool IsConstraintViolated() {
            bool result = false; 
            Index index = ConstraintIndex;
            if (index.HasDuplicates) {
                //
                object[] uniqueKeys = index.GetUniqueKeyValues(); 

                for (int i = 0; i < uniqueKeys.Length; i++) { 
                    Range r = index.FindRecords((object[])uniqueKeys[i]); 
                    if (1 < r.Count) {
                        DataRow[] rows = index.GetRows(r); 
                        string error = ExceptionBuilder.UniqueConstraintViolationText(key.ColumnsReference, (object[])uniqueKeys[i]);
                        for (int j = 0; j < rows.Length; j++) {
                            //
                            rows[j].RowError = error; 
                            foreach(DataColumn dataColumn in key.ColumnsReference){
                                rows[j].SetColumnError(dataColumn, error); 
                            } 
                        }
                        // 
                        result = true;
                    }
                }
            } 
            return result;
        } 
 
        internal override void CheckConstraint(DataRow row, DataRowAction action) {
            if (Table.EnforceConstraints && 
                (action == DataRowAction.Add ||
                 action == DataRowAction.Change ||
                 (action == DataRowAction.Rollback && row.tempRecord != -1))) {
                if (row.HaveValuesChanged(ColumnsReference)) { 
                    if (ConstraintIndex.IsKeyRecordInIndex(row.GetDefaultRecord())) {
                        object[] values = row.GetColumnValues(ColumnsReference); 
                        throw ExceptionBuilder.ConstraintViolation(ColumnsReference, values); 
                    }
                } 
            }
        }

        internal override bool ContainsColumn(DataColumn column) { 
            return key.ContainsColumn(column);
        } 
 
        internal override Constraint Clone(DataSet destination) {
            return Clone(destination, false); 
        }

        internal override Constraint Clone(DataSet destination, bool ignorNSforTableLookup) {
            int iDest; 
            if (ignorNSforTableLookup) {
                iDest = destination.Tables.IndexOf(Table.TableName); 
            } 
            else {
                iDest = destination.Tables.IndexOf(Table.TableName, Table.Namespace, false);// pass false for last param to be backward compatable 
            }

            if (iDest < 0)
                return null; 
            DataTable table = destination.Tables[iDest];
 
            int keys = ColumnsReference.Length; 
            DataColumn[] columns = new DataColumn[keys];
 
            for (int i = 0; i < keys; i++) {
                DataColumn src = ColumnsReference[i];
                iDest = table.Columns.IndexOf(src.ColumnName);
                if (iDest < 0) 
                    return null;
                columns[i] = table.Columns[iDest]; 
            } 

            UniqueConstraint clone = new UniqueConstraint(ConstraintName, columns); 

            // ...Extended Properties
            foreach(Object key in this.ExtendedProperties.Keys) {
               clone.ExtendedProperties[key]=this.ExtendedProperties[key]; 
            }
 
            return clone; 
        }
 
        internal UniqueConstraint Clone(DataTable table) {
            int keys = ColumnsReference.Length;
            DataColumn[] columns = new DataColumn[keys];
 
            for (int i = 0; i < keys; i++) {
                DataColumn src = ColumnsReference[i]; 
                int iDest = table.Columns.IndexOf(src.ColumnName); 
                if (iDest < 0)
                    return null; 
                columns[i] = table.Columns[iDest];
            }

            UniqueConstraint clone = new UniqueConstraint(ConstraintName, columns); 

            // ...Extended Properties 
            foreach(Object key in this.ExtendedProperties.Keys) { 
               clone.ExtendedProperties[key]=this.ExtendedProperties[key];
            } 

            return clone;
        }
 
        /// 
        ///    Gets the array of columns that this constraint affects. 
        ///  
        [
        ResCategoryAttribute(Res.DataCategory_Data), 
        ResDescriptionAttribute(Res.KeyConstraintColumnsDescr),
        ReadOnly(true)
        ]
        public virtual DataColumn[] Columns { 
            get {
                return key.ToArray(); 
            } 
        }
 
        internal DataColumn[] ColumnsReference {
            get {
                return key.ColumnsReference;
            } 
        }
 
        ///  
        ///    Gets
        ///       a value indicating whether or not the constraint is on a primary key. 
        /// 
        [
        ResCategoryAttribute(Res.DataCategory_Data),
        ResDescriptionAttribute(Res.KeyConstraintIsPrimaryKeyDescr) 
        ]
        public bool IsPrimaryKey { 
            get { 
                if (Table == null) {
                    return false; 
                }
                return(this == Table.primaryKey);
            }
        } 

        private void Create(String constraintName, DataColumn[] columns) { 
            for (int i = 0; i < columns.Length; i++) { 
                if (columns[i].Computed) {
                    throw ExceptionBuilder.ExpressionInConstraint(columns[i]); 
                }
            }
            this.key = new DataKey(columns, true);
            ConstraintName = constraintName; 
            NonVirtualCheckState();
        } 
 
        /// 
        ///    Compares this constraint to a second to 
        ///       determine if both are identical.
        /// 
        public override bool Equals(object key2) {
            if (!(key2 is UniqueConstraint)) 
                return false;
 
            return Key.ColumnsEqual(((UniqueConstraint)key2).Key); 
        }
 
        public override Int32 GetHashCode() {
            return base.GetHashCode();
        }
 
        internal override bool InCollection {
            set { 
                base.InCollection = value; 
                if (key.ColumnsReference.Length == 1) {
                    key.ColumnsReference[0].InternalUnique(value); 
                }
            }
        }
 
        internal DataKey Key {
            get { 
                return key; 
            }
        } 

        /// 
        ///    Gets the table to which this constraint belongs.
        ///  
        [
        ResCategoryAttribute(Res.DataCategory_Data), 
        ResDescriptionAttribute(Res.ConstraintTableDescr), 
        ReadOnly(true)
        ] 
        public override DataTable Table {
            get {
                if (key.HasValue) {
                    return key.Table; 
                }
                return null; 
            } 
        }
 
        // misc
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
                        

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