/// <summary>
/// Re load the schema structure of the database from disk
/// </summary>
/// <returns>true if loaded successfully</returns>
public bool Load()
{
try
{
var reader = new io.BinaryReader(io.File.OpenRead(SchemaFilePath));
Schema = DbSchemaConfig.Load(reader);
reader.Dispose();
//link
foreach (var table in Tables)
{
table.Database = this;
foreach (var column in table.Columns)
{
//update
if (!column.Indexed)
{
column.NodePages = 0;
column.ItemPages = 0;
}
column.Table = table;
}
}
;
SaveKeyIndexedKeyOffsets();
return(true);
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
return(false);
}
}
/// <summary>
/// Loads a database schema
/// </summary>
/// <param name="reader">binary reader</param>
/// <returns></returns>
public static DbSchemaConfig Load(io.BinaryReader reader)
{
var schema = new DbSchemaConfig()
{
Flags = (DbSchemaConfigType)reader.ReadUInt32(),
Version = reader.BinaryRead(),
Description = reader.BinaryRead(),
Name = reader.BinaryRead(),
PageSize = reader.ReadInt32(),
_tables = new Dictionary <string, DbTable>()
//Tables = new List<DbTable>()
};
//tables
var pageCount = reader.ReadInt32();
for (var t = 0; t < pageCount; t++)
{
var table = new DbTable()
{
Name = reader.BinaryRead(),
FileName = reader.BinaryRead(),
Generate = reader.ReadBoolean(),
Multikey = reader.ReadBoolean(),
Rows = reader.ReadInt32(),
RowMask = reader.ReadUInt64(),
RowMaskLength = reader.ReadInt32(),
Pager = DbTablePager.Load(reader),
Count = reader.ReadInt32(),
_columns = new Dictionary <string, DbColumn>()
};
//read columns
var columnNameList = new List <string>();
for (var c = 0; c < table.Count; c++)
{
var col = new DbColumn()
{
Indexer = reader.BinaryRead(),
Unique = reader.ReadBoolean(),
Name = reader.BinaryRead(),
Index = reader.ReadInt32(),
Type = reader.BinaryRead(),
Key = reader.ReadBoolean(),
Indexed = reader.ReadBoolean(),
//
NodePages = reader.ReadInt32(),
ItemPages = reader.ReadInt32()
};
if (!table.Add(col))
{
throw new ArgumentException($"duplicated column: {col.Name} on table {table.Name}");
}
columnNameList.Add(col.Name);
}
//check count
if (table.Count != table.Columns.Count())
{
throw new ArgumentException($"invalid table count on: {table.Name}");
}
table._columnNameList = columnNameList.ToArray();
//get key
table.Keys = table.Columns.Where(c => c.Key).ToArray();
var keyCount = table.Keys.Length;
if (table.Multikey)
{
//must have more than one key
table.Key = null;
if (keyCount < 2)
{
throw new ArgumentException($"table: {table} is multi-key and has less than 2 keys");
}
}
else
{
//must have just one key
if (keyCount != 1)
{
throw new ArgumentException($"table: {table} must have one key");
}
table.Key = table.Keys[0];
}
//schema.Tables.Add(table);
schema._tables.Add(table.Name, table);
}
return(schema);
}
