I just finished a .net library with a few useful queries that return strongly typed C# objects for code gen/ t4 templates.
nuget SqlMeta
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github source
/// <summary>
    ///     Get All Table Names
    /// </summary>
    /// <returns></returns>
    public List<string> GetTableNames()
    {
        var sql = @"SELECT name
                    FROM dbo.sysobjects
                    WHERE xtype = 'U' 
                    AND name <> 'sysdiagrams'
                    order by name asc";
        return databaseWrapper.Call(connection => connection.Query<string>(
            sql: sql))
            .ToList();
    }
    /// <summary>
    ///     Get table info by schema and table or null for all
    /// </summary>
    /// <param name="schema"></param>
    /// <param name="table"></param>
    /// <returns></returns>
    public List<SqlTableInfo> GetTableInfo(string schema = null, string table = null)
    {
        var result = new List<SqlTableInfo>();
        var sql = @"SELECT
                    c.TABLE_CATALOG AS [TableCatalog]
                ,   c.TABLE_SCHEMA AS [Schema]
                ,   c.TABLE_NAME AS [TableName]
                ,   c.COLUMN_NAME AS [ColumnName]
                ,   c.ORDINAL_POSITION AS [OrdinalPosition]
                ,   c.COLUMN_DEFAULT AS [ColumnDefault]
                ,   c.IS_NULLABLE AS [Nullable]
                ,   c.DATA_TYPE AS [DataType]
                ,   c.CHARACTER_MAXIMUM_LENGTH AS [CharacterMaxLength]
                ,   c.CHARACTER_OCTET_LENGTH AS [CharacterOctetLenth]
                ,   c.NUMERIC_PRECISION AS [NumericPrecision]
                ,   c.NUMERIC_PRECISION_RADIX AS [NumericPrecisionRadix]
                ,   c.NUMERIC_SCALE AS [NumericScale]
                ,   c.DATETIME_PRECISION AS [DatTimePrecision]
                ,   c.CHARACTER_SET_CATALOG AS [CharacterSetCatalog]
                ,   c.CHARACTER_SET_SCHEMA AS [CharacterSetSchema]
                ,   c.CHARACTER_SET_NAME AS [CharacterSetName]
                ,   c.COLLATION_CATALOG AS [CollationCatalog]
                ,   c.COLLATION_SCHEMA AS [CollationSchema]
                ,   c.COLLATION_NAME AS [CollationName]
                ,   c.DOMAIN_CATALOG AS [DomainCatalog]
                ,   c.DOMAIN_SCHEMA AS [DomainSchema]
                ,   c.DOMAIN_NAME AS [DomainName]
                ,   IsPrimaryKey = CONVERT(BIT, (SELECT
                            COUNT(*)
                        FROM    INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc
                            ,   INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE cu
                        WHERE CONSTRAINT_TYPE = 'PRIMARY KEY'
                        AND tc.CONSTRAINT_NAME = cu.CONSTRAINT_NAME
                        AND tc.TABLE_NAME = c.TABLE_NAME
                        AND cu.TABLE_SCHEMA = c.TABLE_SCHEMA
                        AND cu.COLUMN_NAME = c.COLUMN_NAME)
                    )
                ,   IsIdentity = CONVERT(BIT, (SELECT
                            COUNT(*)
                        FROM sys.objects obj
                        INNER JOIN sys.COLUMNS col
                            ON obj.object_id = col.object_id
                        WHERE obj.type = 'U'
                        AND obj.Name = c.TABLE_NAME
                        AND col.Name = c.COLUMN_NAME
                        AND col.is_identity = 1)
                    )
                FROM INFORMATION_SCHEMA.COLUMNS c
                WHERE (@Schema IS NULL
                        OR c.TABLE_SCHEMA = @Schema)
                    AND (@TableName IS NULL
                        OR c.TABLE_NAME = @TableName)
                    ";
        var columns = databaseWrapper.Call(connection => connection.Query<SqlColumnInfo>(
            sql: sql,
            param: new { Schema = schema, TableName = table },
            commandType: CommandType.Text)
            .ToList());
        var refs = this.GetReferentialConstraints(table: table, schema: schema);
        foreach (var tableName in columns.Select(info => info.TableName).Distinct())
        {
            var tableColumns = columns.Where(info => info.TableName == tableName).ToList();
            var children = refs.Where(c => c.UniqueTableName == tableName).ToList();
            var parents = refs.Where(c => c.TableName == tableName).ToList();
            result.Add(new SqlTableInfo
            {
                TableName = tableName,
                Columns = tableColumns,
                ChildConstraints = children,
                ParentConstraints = parents
            });
        }
        return result;
    }
    public List<SqlReferentialConstraint> GetReferentialConstraints(string table = null, string schema = null)
    {
        //https://technet.microsoft.com/en-us/library/aa175805%28v=sql.80%29.aspx
        //https://technet.microsoft.com/en-us/library/Aa175805.312ron1%28l=en-us,v=sql.80%29.jpg
        //https://msdn.microsoft.com/en-us/library/ms186778.aspx
        var sql = @"
                    SELECT
                        KCU1.CONSTRAINT_NAME AS [ConstraintName]
                    ,   KCU1.TABLE_NAME AS [TableName]
                    ,   KCU1.COLUMN_NAME AS [ColumnName]
                    ,   KCU2.CONSTRAINT_NAME AS [UniqueConstraintName]
                    ,   KCU2.TABLE_NAME AS [UniqueTableName]
                    ,   KCU2.COLUMN_NAME AS [UniqueColumnName]
                    ,   RC.MATCH_OPTION AS [MatchOption]
                    ,   RC.UPDATE_RULE AS [UpdateRule]
                    ,   RC.DELETE_RULE AS [DeleteRule]
                    FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS RC
                    LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE KCU1 ON KCU1.CONSTRAINT_CATALOG = RC.CONSTRAINT_CATALOG
                        AND KCU1.CONSTRAINT_SCHEMA = RC.CONSTRAINT_SCHEMA
                        AND KCU1.CONSTRAINT_NAME = RC.CONSTRAINT_NAME
                    LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE KCU2 ON KCU2.CONSTRAINT_CATALOG = RC.UNIQUE_CONSTRAINT_CATALOG
                        AND KCU2.CONSTRAINT_SCHEMA = RC.UNIQUE_CONSTRAINT_SCHEMA
                        AND KCU2.CONSTRAINT_NAME = RC.UNIQUE_CONSTRAINT_NAME
                    WHERE KCU1.ORDINAL_POSITION = KCU2.ORDINAL_POSITION
                            AND (@Table IS NULL
                                OR KCU1.TABLE_NAME = @Table
                                OR KCU2.TABLE_NAME = @Table)
                            AND (@Schema IS NULL
                                OR KCU1.TABLE_SCHEMA = @Schema
                                OR KCU2.TABLE_SCHEMA = @Schema)
                    ";
        return databaseWrapper.Call(connection => connection.Query<SqlReferentialConstraint>(
            sql: sql,
            param: new { Table = table, Schema = schema },
            commandType: CommandType.Text))
            .ToList();
    }
    /// <summary>
    ///     Get Primary Key Column by schema and table name
    /// </summary>
    /// <param name="schema"></param>
    /// <param name="tableName"></param>
    /// <returns></returns>
    public string GetPrimaryKeyColumnName(string schema, string tableName)
    {
        var sql = @"SELECT
                    B.COLUMN_NAME
                FROM    INFORMATION_SCHEMA.TABLE_CONSTRAINTS A
                    ,   INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE B
                WHERE CONSTRAINT_TYPE = 'PRIMARY KEY'
                    AND A.CONSTRAINT_NAME = B.CONSTRAINT_NAME
                    AND A.TABLE_NAME = @TableName
                    AND A.TABLE_SCHEMA = @Schema";
        return databaseWrapper.Call(connection => connection.Query<string>(
            sql: sql,
            param: new { TableName = tableName, Schema = schema },
            commandType: CommandType.Text))
            .SingleOrDefault();
    }
    /// <summary>
    ///     Get Identity Column by table name
    /// </summary>
    /// <param name="tableName"></param>
    /// <returns></returns>
    public string GetIdentityColumnName(string tableName)
    {
        var sql = @"SELECT
                    c.Name
                FROM sys.objects o
                INNER JOIN sys.columns c ON o.object_id = c.object_id
                WHERE o.type = 'U'
                    AND c.is_identity = 1
                    AND o.Name = @TableName";
        return databaseWrapper.Call(connection => connection.Query<string>(
            sql: sql,
            param: new { TableName = tableName },
            commandType: CommandType.Text))
            .SingleOrDefault();
    }
    /// <summary>
    ///     Get All Stored Procedures by schema
    /// </summary>
    /// <param name="schema"></param>
    /// <param name="procName"></param>
    /// <returns></returns>
    public List<SqlStoredProcedureInfo> GetStoredProcedureInfo(string schema = null, string procName = null)
    {
        var result = new List<SqlStoredProcedureInfo>();
        var sql = @"SELECT
                        SPECIFIC_NAME AS [Name]
                    ,   SPECIFIC_SCHEMA AS [Schema]
                    ,   Created AS [Created]
                    ,   LAST_ALTERED AS [LastAltered]
                    FROM INFORMATION_SCHEMA.ROUTINES
                    WHERE ROUTINE_TYPE = 'PROCEDURE'
                        AND (SPECIFIC_SCHEMA = @Schema
                            OR @Schema IS NULL)
                        AND (SPECIFIC_NAME = @ProcName
                            OR @ProcName IS NULL)
                        AND ((SPECIFIC_NAME NOT LIKE 'sp_%'
                                AND SPECIFIC_NAME NOT LIKE 'procUtils_GenerateClass'
                                AND (SPECIFIC_SCHEMA = @Schema
                                    OR @Schema IS NULL))
                            OR SPECIFIC_SCHEMA <> @Schema)";
        var sprocs = databaseWrapper.Call(connection => connection.Query<SqlStoredProcedureInfo>(
            sql: sql,
            param: new { Schema = schema, ProcName = procName },
            commandType: CommandType.Text).ToList());
        foreach (var s in sprocs)
        {
            s.Parameters = GetStoredProcedureInputParameters(sprocName: s.Name, schema: schema);
            s.ResultColumns = GetColumnInfoFromStoredProcResult(storedProcName: s.Name, schema: schema);
            result.Add(s);
        }
        return result;
    }
    /// <summary>
    ///     Get Column info from Stored procedure result set
    /// </summary>
    /// <param name="schema"></param>
    /// <param name="storedProcName"></param>
    /// <returns></returns>
    public List<DataColumn> GetColumnInfoFromStoredProcResult(string schema, string storedProcName)
    {
        //this one actually needs to use the dataset because it has the only accurate information about columns and if they can be null or not.
        var sb = new StringBuilder();
        if (!String.IsNullOrEmpty(schema))
        {
            sb.Append(String.Format("exec [{0}].[{1}] ", schema, storedProcName));
        }
        else
        {
            sb.Append(String.Format("exec [{0}] ", storedProcName));
        }
        var prms = GetStoredProcedureInputParameters(schema, storedProcName);
        var count = 1;
        foreach (var param in prms)
        {
            sb.Append(String.Format("{0}=null", param.Name));
            if (count < prms.Count)
            {
                sb.Append(", ");
            }
            count++;
        }
        var ds = new DataSet();
        using (var sqlConnection = (SqlConnection)databaseWrapper.GetOpenDbConnection())
        {
            using (var sqlAdapter = new SqlDataAdapter(sb.ToString(), sqlConnection))
            {
                if (sqlConnection.State != ConnectionState.Open) sqlConnection.Open();
                sqlAdapter.SelectCommand.ExecuteReader(CommandBehavior.SchemaOnly);
                sqlConnection.Close();
                sqlAdapter.FillSchema(ds, SchemaType.Source, "MyTable");
            }
        }
        var list = new List<DataColumn>();
        if (ds.Tables.Count > 0)
        {
            list = ds.Tables["MyTable"].Columns.Cast<DataColumn>().ToList();
        }
        return list;
    }
    /// <summary>
    ///     Get the input parameters for a stored procedure
    /// </summary>
    /// <param name="schema"></param>
    /// <param name="sprocName"></param>
    /// <returns></returns>
    public List<SqlParameterInfo> GetStoredProcedureInputParameters(string schema = null, string sprocName = null)
    {
        var sql = @"SELECT
                    SCHEMA_NAME(schema_id) AS [Schema]
                ,   P.Name AS Name
                ,   @ProcName AS ProcedureName
                ,   TYPE_NAME(P.user_type_id) AS [ParameterDataType]
                ,   P.max_length AS [MaxLength]
                ,   P.Precision AS [Precision]
                ,   P.Scale AS Scale
                ,   P.has_default_value AS HasDefaultValue
                ,   P.default_value AS DefaultValue
                ,   P.object_id AS ObjectId
                ,   P.parameter_id AS ParameterId
                ,   P.system_type_id AS SystemTypeId
                ,   P.user_type_id AS UserTypeId
                ,   P.is_output AS IsOutput
                ,   P.is_cursor_ref AS IsCursor
                ,   P.is_xml_document AS IsXmlDocument
                ,   P.xml_collection_id AS XmlCollectionId
                ,   P.is_readonly AS IsReadOnly
                FROM sys.objects AS SO
                INNER JOIN sys.parameters AS P ON SO.object_id = P.object_id
                WHERE SO.object_id IN (SELECT
                            object_id
                        FROM sys.objects
                        WHERE type IN ('P', 'FN'))
                    AND (SO.Name = @ProcName
                        OR @ProcName IS NULL)
                    AND (SCHEMA_NAME(schema_id) = @Schema
                        OR @Schema IS NULL)
                ORDER BY P.parameter_id ASC";
        var result = databaseWrapper.Call(connection => connection.Query<SqlParameterInfo>(
            sql: sql,
            param: new { Schema = schema, ProcName = sprocName },
            commandType: CommandType.Text))
            .ToList();
        return result;
    }
Foreign Key Metadata