`EDBMMErrorCodes`

Central error code constants, structured error type, and exception class shared by all library units (EDBMMClient, EDBMMHttp, EDBMMUtils).

Add EDBMMErrorCodes to your uses clause when your code checks specific EC_* constants directly (e.g. if Script.LastError.Code = EC_HTTP_TIMEOUT then ...). The TAppError type itself is visible through EDBMMClient without explicitly listing this unit.

Name	Kind
`EC_*` constants	Integer constants
`TAppError`	Record
`EAppError`	Exception class
`AppErrorMsg`	Function

## Error Code Ranges

Range	Source
0	No error (`EC_NONE`)
1000–1999	PHP API (`EC_PHP_*`)
2000–2999	MySQL / MariaDB engine (`EC_MYSQL_*`)
3000–3999	ElevateDB engine (`EC_EDB_*`)
4000–4999	HTTP transport layer (`EC_HTTP_*`)
5000–5999	Internal serialisation utilities (`EC_UTILS_*`)
6000–6999	EDBMMClient library (`EC_CLIENT_*`)
7000–7999	URESTPipeline / SQL Console (`EC_PIPELINE_*`)
8000–8999	EDB2MySQL application (`EC_APP_*`)

The most commonly encountered constants in library use:

Constant	Code	Meaning
`EC_NONE`	0	No error; default-initialised `TAppError`
`EC_PHP_UNAUTHORIZED`	1004	Wrong or missing API key
`EC_PHP_MEMORY_EXHAUSTED`	1018	PHP `memory_limit` exceeded
`EC_HTTP_CONNECTION`	4001	Network connection failure
`EC_HTTP_TIMEOUT`	4002	HTTP request timed out
`EC_HTTP_NON_JSON`	4004	Non-JSON response (unclassified)
`EC_CLIENT_NO_CONNECTION`	6001	No `TMMConnection` assigned
`EC_CLIENT_SCRIPT_EXEC`	6005	`script_run` failed
`EC_CLIENT_CANCELLED`	6012	`Cancel` was called
`EC_CLIENT_BLOB_CHUNK`	6017	`blob_chunk` upload failed

The full list of EC_* constants is in the unit source. Each constant has a corresponding EM_* message template used internally when building TAppError values; EM_* templates are also declared in the unit but not normally referenced directly in application code.

## TAppError

TAppError = record
  Code      : Integer;  // EC_* constant; 0 = no error
  Msg       : string;   // human-readable description
  NativeCode: Integer;  // original engine error number (MySQL/EDB); 0 = n/a
  NativeMsg : string;   // original engine error message; '' = n/a

  function IsError: Boolean;  // True when Code <> 0

  class function Make(ACode: Integer; const AMsg: string;
    ANativeCode: Integer = 0; const ANativeMsg: string = ''): TAppError; static;

  class function MakeFmt(ACode: Integer; const Args: array of const;
    ANativeCode: Integer = 0; const ANativeMsg: string = ''): TAppError; static;

  class function FromException(ACode: Integer; E: Exception;
    ANativeCode: Integer = 0): TAppError; static;
end;

Value type (record). A default-initialised TAppError (all fields zero / empty) represents the absence of an error: IsError returns False and Code = EC_NONE.

NativeCode / NativeMsg are populated for MySQL (2xxx) and ElevateDB (3xxx) errors only; zero / empty for all other ranges.

Member	Description
`IsError`	Returns `True` when `Code <> 0`
`Make`	Build from explicit code, message, and optional native error info
`MakeFmt`	Build from a code and `Format()`-style arguments applied to the `EM_*` template
`FromException`	Build from a caught exception: `Msg := E.Message`, `Code := ACode`

TAppError is exposed as a read-only property on all three classes: TMMConnection (via TMMHttpClient.LastError), TMMScript.LastError, TMMUpdater.LastError, and TMMUpdater.PrefetchError.

## EAppError

EAppError = class(Exception)
  constructor Create(const AError: TAppError); overload;
  constructor CreateCode(ACode: Integer; const AMsg: string;
    ANativeCode: Integer = 0; const ANativeMsg: string = ''); overload;
  property Error: TAppError read FError;
end;

Exception wrapper for TAppError. Used when a structured error must propagate across call boundaries (e.g. between pipeline stages). Exception.Message equals Error.Msg. Rarely needed in application code; the library catches EAppError internally and converts it to result properties.

## AppErrorMsg

function AppErrorMsg(ACode: Integer): string;

Returns the EM_* message template string for a given EC_* code. Falls back to EM_UNKNOWN for unrecognised codes. Used internally when building TAppError values; rarely needed in application code.

`EDBMMErrorCodes`

Contents

See Also