/// <summary>
/// Create a foreign key constraint on two tables.
/// </summary>
/// <param name="dataModelSchema">The parent data model schema.</param>
/// <param name="xmlSchemaKeyref">The XmlSchema object that describes the foreignn key relation.</param>
public RelationSchema(DataModelSchema dataModelSchema, XmlSchemaKeyref xmlSchemaKeyref)
{
// Initialize the object.
this.name = xmlSchemaKeyref.Name;
// This will search through each of the tables looking for the parent and child components of the relation.
foreach (KeyValuePair <string, TableSchema> keyValuePair in dataModelSchema.Tables)
{
ConstraintSchema constraintSchema;
// This is the parent component of the relation.
if (keyValuePair.Value.Constraints.TryGetValue(xmlSchemaKeyref.Refer.Name, out constraintSchema))
{
UniqueConstraintSchema uniqueConstraintSchema = constraintSchema as UniqueConstraintSchema;
this.parentColumns = uniqueConstraintSchema.Columns;
this.parentTable = uniqueConstraintSchema.Table;
this.parentKeyConstraint = uniqueConstraintSchema;
}
// This is the child part of the relation.
if (keyValuePair.Value.Constraints.TryGetValue(xmlSchemaKeyref.Name, out constraintSchema))
{
ForeignKeyConstraintSchema foreignKeyConstraintSchema = constraintSchema as ForeignKeyConstraintSchema;
this.childTable = foreignKeyConstraintSchema.Table;
this.childColumns = foreignKeyConstraintSchema.Columns;
this.childKeyConstraint = foreignKeyConstraintSchema;
}
}
}
/// <summary>
/// Creates an array of values from a unique constraint that can be used for finding records.
/// </summary>
/// <param name="uniqueConstraintSchema">A description of a unique constraint.</param>
/// <returns>An array of expressions that can be used as a key for finding records in a table.</returns>
public CodeExpression[] CreateKey(UniqueConstraintSchema uniqueConstraintSchema)
{
// This will cycle through all the foreign and simple parameters looking for any columns that match up to the child
// columns of the constraint. When found, they are placed in the array in the proper order to match up against the
// given unique constraint.
List <CodeExpression> keys = new List <CodeExpression>();
foreach (ColumnSchema uniqueColumn in uniqueConstraintSchema.Columns)
{
foreach (KeyValuePair <string, ExternalParameterItem> parameterPair in this.ExternalParameterItems)
{
// This correlates the unique constraint columns with the variables that have been created in the method to
// hold the key values from the foreign tables. These variables exist outside of the conditional logic that
// finds the parent row, so if the parent key is null, these values will also be null. However, since they're
// still declared, they can be used to construct keys, which is useful when they're optional values.
if (parameterPair.Value is ForeignKeyConstraintParameterItem)
{
ForeignKeyConstraintParameterItem foreignKeyConstraintParameterItem = parameterPair.Value as ForeignKeyConstraintParameterItem;
ForeignKeyConstraintSchema foreignKeyConstraintSchema = foreignKeyConstraintParameterItem.ForeignKeyConstraintSchema;
for (int columnIndex = 0; columnIndex < foreignKeyConstraintSchema.Columns.Length; columnIndex++)
{
if (uniqueColumn == foreignKeyConstraintSchema.Columns[columnIndex])
{
foreach (ForeignKeyVariableItem foreignKeyVariableItem in foreignKeyConstraintParameterItem.ForeignKeyVariables)
{
if (foreignKeyConstraintSchema.Columns[columnIndex] == foreignKeyVariableItem.ColumnSchema)
{
keys.Add(foreignKeyVariableItem.Expression);
}
}
}
}
}
// This will match the columns described in the simple parameters to the columns in the unique constraint.
if (parameterPair.Value is SimpleParameterItem)
{
SimpleParameterItem simpleParameterItem = parameterPair.Value as SimpleParameterItem;
if (uniqueColumn == simpleParameterItem.ColumnSchema)
{
keys.Add(new CodeVariableReferenceExpression(CommonConversion.ToCamelCase(simpleParameterItem.ColumnSchema.Name)));
}
}
}
}
// This array can be used as a key to find the record in a table.
return(keys.ToArray());
}
/// <summary>
/// The foreign constraints can only be evaluated after all the tables, keys and unique constraints have been evaluated.
/// </summary>
/// <param name="xmlSchema"></param>
private void SecondPass(XmlSchemaSet xmlSchemaSet)
{
// This is the second pass through the schemas. Once the tables, keys and unique constraints have been evaluated,
// then the foreign constraints can be constructed and applied to the parent and child tables.
foreach (XmlSchemaElement xmlSchemaElement in xmlSchemaSet.GlobalElements.Values)
{
// Only the Microsoft DataSet element is evaluated for foreign keys.
if (ObjectSchema.IsDataSetElement(xmlSchemaElement))
{
// This will examine each of the constraints looking for a foreign key description.
foreach (XmlSchemaIdentityConstraint xmlSchemaIdentityConstraint in xmlSchemaElement.Constraints)
{
// Evaluate the foreign keys in the data model.
if (xmlSchemaIdentityConstraint is XmlSchemaKeyref)
{
// This object can be used as a foreign key constraint and, optionally, can be used to describe a
// parent/child relationship.
XmlSchemaKeyref xmlSchemaKeyref = xmlSchemaIdentityConstraint as XmlSchemaKeyref;
// This creates a foreign key.
ForeignKeyConstraintSchema foreignKeyConstraintSchema = new ForeignKeyConstraintSchema(this, xmlSchemaIdentityConstraint as XmlSchemaKeyref);
// Foreign constraint schemas are always added to the list of constraints on a table. They can also
// conditionally become the source for a relationship between two tables.
foreignKeyConstraintSchema.Table.Add(foreignKeyConstraintSchema);
// Unless specifically instructed to supress the relation, it will be created add added to both the
// parent and child tables as well as the data model.
XmlAttribute isConstraintOnlyAttribute = ObjectSchema.GetUnhandledAttribute(xmlSchemaIdentityConstraint, QualifiedName.ConstraintOnly);
if (isConstraintOnlyAttribute == null || !Convert.ToBoolean(isConstraintOnlyAttribute.Value))
{
RelationSchema relationSchema = new RelationSchema(this, xmlSchemaKeyref);
relationSchema.ParentTable.ChildRelations.Add(relationSchema.Name, relationSchema);
relationSchema.ChildTable.ParentRelations.Add(relationSchema.Name, relationSchema);
this.Relations.Add(relationSchema.Name, relationSchema);
}
}
}
}
}
}
/// <summary>
/// Creates the element that describes a foreign constraint.
/// </summary>
/// <param name="foreignConstraintSchema">A description of a foreign constraint.</param>
/// <returns>An element that can be used in an XML Schema document to describe a foreign constraint.</returns>
private static XElement CreateForeignKey(ForeignKeyConstraintSchema foreignKeyConstraintSchema)
{
// <xs:keyref name="FK_Entity_AccessControl" refer="EntityKey" msprop:rel_Generator_UserRelationName="FK_Entity_AccessControl"
// msprop:rel_Generator_RelationVarName="relationFK_Entity_AccessControl" msprop:rel_Generator_UserChildTable="AccessControl"
// msprop:rel_Generator_UserParentTable="Entity" msprop:rel_Generator_ParentPropName="EntityRow"
// msprop:rel_Generator_ChildPropName="GetAccessControlRows">
// <xs:selector xpath=".//mstns:AccessControl" />
// <xs:field xpath="mstns:EntityId" />
// </xs:keyref>
XElement foreignElement = new XElement(
SchemaScrubber.xs + "keyref",
new XAttribute("name", foreignKeyConstraintSchema.Name),
new XAttribute("refer", foreignKeyConstraintSchema.RelatedTable.GetUniqueConstraint(foreignKeyConstraintSchema.RelatedColumns).Name),
new XAttribute(SchemaScrubber.msprop + "rel_Generator_UserRelationName", foreignKeyConstraintSchema.Name),
new XAttribute(SchemaScrubber.msprop + "rel_Generator_RelationVarName", String.Format("relation{0}", foreignKeyConstraintSchema.Name)),
new XAttribute(SchemaScrubber.msprop + "rel_Generator_UserChildTable", foreignKeyConstraintSchema.Table.Name),
new XAttribute(SchemaScrubber.msprop + "rel_Generator_UserParentTable", foreignKeyConstraintSchema.RelatedTable.Name),
new XAttribute(SchemaScrubber.msprop + "rel_Generator_ParentPropName", String.Format("{0}Row", foreignKeyConstraintSchema.RelatedTable.Name)),
new XAttribute(SchemaScrubber.msprop + "rel_Generator_ChildPropName", String.Format("Get{0}Rows", foreignKeyConstraintSchema.Table.Name)));
foreignElement.Add(
new XElement(
SchemaScrubber.xs + "selector",
new XAttribute("xpath", String.Format(".//mstns:{0}", foreignKeyConstraintSchema.Table.Name))));
foreach (ColumnSchema columnSchema in foreignKeyConstraintSchema.Columns)
{
foreignElement.Add(
new XElement(
SchemaScrubber.xs + "field",
new XAttribute("xpath", String.Format("mstns:{0}", columnSchema.Name))));
}
// This describes a foreign constraint on a table.
return(foreignElement);
}
/// <summary>
/// Generates the DDL for a table.
/// </summary>
/// <param name="streamWriter">The file to which the DDL is written.</param>
/// <param name="tableSchema">The schema description of the table.</param>
private static void GenerateTable(StreamWriter streamWriter, TableSchema tableSchema)
{
// Generate the prolog for this table.
streamWriter.WriteLine("/* The {0} Table */", tableSchema.Name);
// Generate a prolog showing the time of creation and the current version of the table for the log file.
streamWriter.WriteLine("if not exists (select * from \"VersionControl\" where \"Name\" = '{0}')", tableSchema.Name);
streamWriter.WriteLine(" print convert(varchar, getdate(), 120) + 'Z <Undefined>: \"{0}\" doesn''t exist in the catalogs.'", tableSchema.Name);
streamWriter.WriteLine("else");
streamWriter.WriteLine("begin");
streamWriter.WriteLine(" declare @revision \"decimal\"");
streamWriter.WriteLine(" select @revision = \"Revision\" from \"VersionControl\" where \"Name\" = '{0}'", tableSchema.Name);
streamWriter.WriteLine(" print convert(varchar, getdate(), 120) + 'Z Table: \"{0}\", Initial revision: ' + convert(varchar, @revision)", tableSchema.Name);
streamWriter.WriteLine("end");
streamWriter.WriteLine();
// The table schema is only run if the version control table indicates that the update is needed.
streamWriter.WriteLine("/* This checks the version control table to determine if an update is needed. */");
streamWriter.WriteLine("declare @currentRevision \"decimal\"");
streamWriter.WriteLine("declare @requiredRevision \"decimal\"");
streamWriter.WriteLine("select @currentRevision = isnull((select \"Revision\" from \"VersionControl\" where \"VersionControl\".\"Name\" = '{0}'), -1.0)", tableSchema.Name);
streamWriter.WriteLine("select @requiredRevision = isnull((select \"Revision\" from \"VersionHistory\", \"VersionTag\"");
streamWriter.WriteLine(" where \"VersionHistory\".\"Active\" = 1 and \"VersionHistory\".\"Label\" = \"VersionTag\".\"Label\" and \"VersionTag\".\"Name\" = '{0}'), {1})", tableSchema.Name, tableSchema.DataModel.Version);
streamWriter.WriteLine("if @currentRevision < {0} and {0} <= @requiredRevision", tableSchema.DataModel.Version);
streamWriter.WriteLine("begin");
streamWriter.WriteLine("");
// This transaction will remove the previous version of the table and create the new version.
streamWriter.WriteLine(" /* The revision must be completed as a unit. */");
streamWriter.WriteLine(" begin transaction");
streamWriter.WriteLine("");
streamWriter.WriteLine(" /* Remove the object and any dependancies. */");
foreach (KeyValuePair <string, ConstraintSchema> constraintPair in tableSchema.Constraints)
{
if (constraintPair.Value is ForeignKeyConstraintSchema)
{
ForeignKeyConstraintSchema foreignKeyConstraintSchema = constraintPair.Value as ForeignKeyConstraintSchema;
streamWriter.WriteLine(" if exists (select * from sysobjects where type = 'F' and name = '{0}')", foreignKeyConstraintSchema.Name);
streamWriter.WriteLine(" alter table \"{0}\" drop constraint \"{1}\"", foreignKeyConstraintSchema.Table.Name, foreignKeyConstraintSchema.Name);
}
}
streamWriter.WriteLine(" if exists (select * from sysobjects where type = 'U' and name = '{0}')", tableSchema.Name);
streamWriter.WriteLine(" drop table \"{0}\"", tableSchema.Name);
streamWriter.WriteLine("");
// The table is described here.
streamWriter.WriteLine(" /* Create the table. */");
streamWriter.WriteLine(String.Format(" create table \"{0}\" (", tableSchema.Name));
// Generate each of the column descriptions.
foreach (ColumnSchema columnSchema in tableSchema.Columns.Values)
{
streamWriter.WriteLine(String.Format(" \"{0}\" {1} {2},", columnSchema.Name, GetSqlDataType(columnSchema),
columnSchema.IsNullable ? "null" : "not null"));
}
// These columns are always included for house keeping.
streamWriter.WriteLine(" \"IsArchived\" \"bit\" not null,");
streamWriter.WriteLine(" \"IsDeleted\" \"bit\" not null,");
// The table is always generated on the primary (default) device.
streamWriter.WriteLine(" ) on \"PRIMARY\"");
streamWriter.WriteLine("");
// Generate the keys, indices and defaults for this table.
GenerateKeys(streamWriter, tableSchema);
GenerateIndices(streamWriter, tableSchema);
GenerateDefaults(streamWriter, tableSchema);
// This will update the version control table to indicate that the table was updated to the new version.
streamWriter.WriteLine(" /* Update the versionControl table to reflect the change. */");
streamWriter.WriteLine(" if exists (select * from \"VersionControl\" where \"Name\" = '{0}')", tableSchema.Name);
streamWriter.WriteLine(" update \"VersionControl\" set \"Revision\" = {0} where \"Name\" = '{1}'", tableSchema.DataModel.Version, tableSchema.Name);
streamWriter.WriteLine(" else");
streamWriter.WriteLine(" insert \"VersionControl\" (\"Name\", \"Revision\") select '{0}', {1}", tableSchema.Name, tableSchema.DataModel.Version);
streamWriter.WriteLine("");
// Commit or reject the changes to the table.
streamWriter.WriteLine(" /* Commit the changes to the table. */");
streamWriter.WriteLine(" commit transaction");
streamWriter.WriteLine("");
streamWriter.WriteLine("end");
streamWriter.WriteLine("go");
streamWriter.WriteLine("");
// Generate the epilog for a successful update.
streamWriter.WriteLine("if @@error = 0");
streamWriter.WriteLine("begin");
streamWriter.WriteLine(" declare @newRevision \"decimal\"");
streamWriter.WriteLine(" select @newRevision = \"Revision\" from \"VersionControl\" where \"Name\" = '{0}'", tableSchema.Name);
streamWriter.WriteLine(" print convert(varchar, getdate(), 120) + 'Z Table: \"{0}\", Final revision: ' + convert(varchar, @newRevision)", tableSchema.Name);
streamWriter.WriteLine("end");
streamWriter.WriteLine("else");
streamWriter.WriteLine("begin");
streamWriter.WriteLine(" declare @oldRevision \"decimal\"");
streamWriter.WriteLine(" select @oldRevision = isnull((select \"Revision\" from \"VersionControl\" where \"Name\" = '{0}'), 0.0)", tableSchema.Name);
streamWriter.WriteLine(" print convert(varchar, getdate(), 120) + 'Z Table: \"{0}\", Error upgrading from revision: ' + convert(varchar, @oldRevision)", tableSchema.Name);
streamWriter.WriteLine("end");
streamWriter.WriteLine("go");
streamWriter.WriteLine("");
}
