private bool ColumnsEqual(List <ColumnObject> columnsA, List <ColumnObject> columnsB, Options options)
{
if (columnsA.Count != columnsB.Count)
{
return(false);
}
var columnsBCopy = new List <ColumnObject>(columnsB);
foreach (ColumnObject columnA in columnsA)
{
ColumnObject equivalentColumn = null;
int loopLength = columnsBCopy.Count;
for (int i = 0; i < loopLength; i++)
{
ColumnObject columnB = columnsBCopy[i];
// If a column with the same name exists, then the column is not being removed anymore
// and we need to do a deeper check on the columns to see if they are equal
if (columnA.FullyQualifiedName == columnB.FullyQualifiedName)
{
equivalentColumn = columnB;
columnsBCopy[i] = columnsBCopy.Last();
columnsBCopy.RemoveAt(loopLength - 1);
break;
}
}
// If there was no equivalent object, it is a new column so end here
if (equivalentColumn == null)
{
return(false);
}
// If the columns have the same name but are not complete equal, it has been modified
if (!columnA.Equals(equivalentColumn, options))
{
return(false);
}
}
return(true);
}
// TODO Indexes, Constraints, etc
public IEnumerable <IScriptBlock> AlterTo(IDatabaseObject obj, Options options)
{
if (obj is TableObject == false)
{
throw new InvalidOperationException("Cannot alter table to an object that is not a table");
}
var blocks = new List <IScriptBlock>();
var otherTable = obj as TableObject;
List <ColumnObject> modifiedColumns = new List <ColumnObject>();
List <ColumnObject> additionalColumns = new List <ColumnObject>();
// Start off assuming all columns will be removed, and we take items out of the list as we compare
List <ColumnObject> removedColumns = new List <ColumnObject>(this.Columns);
// Find all the modified and additional columns
foreach (ColumnObject columnA in otherTable.Columns)
{
ColumnObject equivalentColumn = null;
int loopLength = removedColumns.Count;
for (int i = 0; i < loopLength; i++)
{
ColumnObject columnB = removedColumns[i];
// If a column with the same name exists, then the column is not being removed anymore
// and we need to do a deeper check on the columns to see if they are equal
if (columnA.FullyQualifiedName == columnB.FullyQualifiedName)
{
equivalentColumn = columnB;
removedColumns[i] = removedColumns.Last();
removedColumns.RemoveAt(loopLength - 1);
break;
}
}
// If there was no equivalent object, it is a new column so end here
if (equivalentColumn == null)
{
additionalColumns.Add(columnA);
continue;
}
// If the columns have the same name but are not complete equal, it has been modified
if (!columnA.Equals(equivalentColumn, options))
{
modifiedColumns.Add(columnA);
}
}
// Drop columns that should no longer be on the table
if (removedColumns.HasItems())
{
var block = new SqlBlock(BlockType.Alter, this.TableName, ObjectType.Column);
foreach (var column in removedColumns)
{
block.Append("ALTER TABLE ");
block.Append(this.FullyQualifiedName);
block.Append(" DROP COLUMN ");
block.AppendLine(column.ColumnName);
block.AppendLine("GO");
}
blocks.Add(block);
}
// Add new columns
if (additionalColumns.HasItems())
{
var block = new SqlBlock(BlockType.Alter, this.TableName, ObjectType.Column);
foreach (var column in additionalColumns)
{
block.Append("ALTER TABLE ");
block.Append(this.FullyQualifiedName);
block.Append(" ADD ");
block.AppendLine(column.GetColumnDefinition());
block.AppendLine("GO");
}
blocks.Add(block);
}
// Modify existing columns
if (modifiedColumns.HasItems())
{
var block = new SqlBlock(BlockType.Alter, this.TableName, ObjectType.Column);
foreach (var column in modifiedColumns)
{
block.Append("ALTER TABLE ");
block.Append(this.FullyQualifiedName);
block.Append(" ALTER COLUMN ");
block.AppendLine(column.GetColumnDefinition());
block.AppendLine("GO");
}
blocks.Add(block);
}
return(blocks);
}
