/// <summary>
/// 转换源表达式的数据类型。
/// </summary>
/// <param name="sourceExp">要转换的源表达式。</param>
/// <param name="dbType">要转换的类型。</param>
/// <returns></returns>
public virtual string Convert(object sourceExp, DbType dbType)
{
switch (dbType)
{
case DbType.AnsiString:
return(string.Format("CAST({0} AS VARCHAR)", sourceExp));
case DbType.AnsiStringFixedLength:
return(string.Format("CAST({0} AS CHAR)", sourceExp));
case DbType.Binary:
return(string.Format("CAST({0} AS VARBINARY)", sourceExp));
case DbType.Boolean:
return(string.Format("CAST({0} AS BIT)", sourceExp));
case DbType.Byte:
return(string.Format("CAST({0} AS TINYINT)", sourceExp));
case DbType.Currency:
return(string.Format("CAST({0} AS MONEY)", sourceExp));
case DbType.Date:
return(string.Format("CAST({0} AS DATETIME)", sourceExp));
case DbType.DateTime:
return(string.Format("CAST({0} AS DATETIME)", sourceExp));
case DbType.DateTime2:
return(string.Format("CAST({0} AS DATETIME2)", sourceExp));
case DbType.DateTimeOffset:
return(string.Format("CAST({0} AS DATETIMEOFFSET)", sourceExp));
case DbType.Decimal:
return(string.Format("CAST({0} AS DECIMAL)", sourceExp));
case DbType.Double:
return(string.Format("CAST({0} AS DOUBLE PRECISION)", sourceExp));
case DbType.Guid:
return(string.Format("CAST({0} AS UNIQUEIDENTIFIER)", sourceExp));
case DbType.Int16:
return(string.Format("CAST({0} AS SMALLINT)", sourceExp));
case DbType.Int32:
return(string.Format("CAST({0} AS INT)", sourceExp));
case DbType.Int64:
return(string.Format("CAST({0} AS BIGINT)", sourceExp));
case DbType.SByte:
break;
case DbType.Single:
return(string.Format("CAST({0} AS REAL)", sourceExp));
case DbType.String:
return(string.Format("CAST({0} AS NVARCHAR)", sourceExp));
case DbType.StringFixedLength:
return(string.Format("CAST({0} AS NCHAR)", sourceExp));
case DbType.Time:
break;
case DbType.UInt16:
break;
case DbType.UInt32:
break;
case DbType.UInt64:
break;
case DbType.VarNumeric:
break;
case DbType.Xml:
return(string.Format("CAST({0} AS XML)", sourceExp));
}
return(ExceptionHelper.ThrowSyntaxConvertException(dbType));
}
/// <summary>
/// 根据数据类型生成相应的列。
/// </summary>
/// <param name="dbType">数据类型。</param>
/// <param name="length">数据长度。</param>
/// <param name="precision">数值的精度。</param>
/// <param name="scale">数值的小数位。</param>
/// <returns></returns>
public string Column(DbType dbType, int?length, int?precision, int?scale = new int?())
{
switch (dbType)
{
case DbType.AnsiString:
if (length == null)
{
return("VARCHAR(255)");
}
if (length > 8000)
{
return("NTEXT");
}
return(string.Format("VARCHAR({0})", length));
case DbType.AnsiStringFixedLength:
return(length == null ? "CHAR(255)" : string.Format("CHAR({0})", length));
case DbType.Binary:
if (length == null)
{
return("VARBINARY(8000)");
}
if (length > 8000)
{
return("IMAGE");
}
return(string.Format("VARBINARY({0})", length));
case DbType.Boolean:
return("BIT");
case DbType.Byte:
return("TINYINT");
case DbType.Currency:
return("MONEY");
case DbType.Date:
return("DATETIME");
case DbType.DateTime:
return("DATETIME");
case DbType.DateTime2:
return("DATETIME2");
case DbType.DateTimeOffset:
return("DATETIMEOFFSET");
case DbType.Decimal:
if (precision == null && scale == null)
{
return("DECIMAL(19, 5)");
}
if (precision == null)
{
return(string.Format("DECIMAL(19, {0})", scale));
}
if (scale == null)
{
return(string.Format("DECIMAL({0}, 5)", precision));
}
return(string.Format("DECIMAL({0}, {1})", precision, scale));
case DbType.Double:
return("DOUBLE PRECISION");
case DbType.Guid:
return("UNIQUEIDENTIFIER");
case DbType.Int16:
return("SMALLINT");
case DbType.Int32:
return("INT");
case DbType.Int64:
return("BIGINT");
case DbType.SByte:
return("TINYINT");
case DbType.Single:
return("REAL");
case DbType.String:
if (length == null)
{
return("VARCHAR(255)");
}
if (length > 8000)
{
return("NTEXT");
}
return(string.Format("VARCHAR({0})", length));
case DbType.StringFixedLength:
if (length == null)
{
return("NCHAR(255)");
}
return(string.Format("NCHAR({0})", length));
case DbType.Time:
return("DATETIME");
case DbType.UInt16:
break;
case DbType.UInt32:
break;
case DbType.UInt64:
break;
case DbType.VarNumeric:
break;
case DbType.Xml:
return("XML");
}
return(ExceptionHelper.ThrowSyntaxCreteException(dbType));
}
/// <summary>
/// 根据数据类型生成相应的列。
/// </summary>
/// <param name="dbType">数据类型。</param>
/// <param name="length">数据长度。</param>
/// <param name="precision">数值的精度。</param>
/// <param name="scale">数值的小数位。</param>
/// <returns></returns>
public string Column(DbType dbType, int?length, int?precision, int?scale = new int?())
{
switch (dbType)
{
case DbType.String:
case DbType.AnsiString:
if (length == null || length <= 255)
{
return(string.Format("VARCHAR({0})", length ?? 255));
}
if (length > 255 && length <= 65535)
{
return("TEXT");
}
//length > 65535 && length <= 16777215
return("MEDIUMTEXT");
case DbType.StringFixedLength:
case DbType.AnsiStringFixedLength:
if (length == null || length <= 255)
{
return(string.Format("CHAR({0})", length ?? 255));
}
if (length > 255 && length <= 65535)
{
return("TEXT");
}
//length > 65535 && length <= 16777215
return("MEDIUMTEXT");
case DbType.Guid:
return("VARCHAR(40)");
case DbType.Binary:
if (length == null || length <= 127)
{
return("LONGBLOB");
}
if (length > 127 && length <= 65535)
{
return("BLOB");
}
//length > 65535 && length <= 16777215
return("MEDIUMBLOB");
case DbType.Decimal:
if (precision == null && scale == null)
{
return("DECIMAL(19, 5)");
}
if (precision == null)
{
return(string.Format("DECIMAL(19, {0})", scale));
}
if (scale == null)
{
return(string.Format("DECIMAL({0}, 5)", precision));
}
return(string.Format("DECIMAL({0}, {1})", precision, scale));
case DbType.Double:
return("DOUBLE");
case DbType.Single:
return("FLOAT");
case DbType.Boolean:
return("TINYINT(1)");
case DbType.Byte:
return("TINY INT");
case DbType.Currency:
return("MONEY");
case DbType.Int16:
return("SMALLINT");
case DbType.Int32:
return("INT");
case DbType.Int64:
return("BIGINT");
case DbType.SByte:
return("TINYINT");
case DbType.UInt16:
return("SMALLINT");
case DbType.UInt32:
return("MEDIUMINT");
case DbType.UInt64:
return("BIT");
case DbType.Date:
return("DATE");
case DbType.DateTime:
return("DATETIME");
case DbType.Time:
return("TIME");
}
return(ExceptionHelper.ThrowSyntaxCreteException(dbType));
}
