diff options
Diffstat (limited to 'lib/impure/db_mysql.nim')
| -rwxr-xr-x | lib/impure/db_mysql.nim | 158 |
1 files changed, 93 insertions, 65 deletions
diff --git a/lib/impure/db_mysql.nim b/lib/impure/db_mysql.nim index 386da0cf7..ee37a88c3 100755 --- a/lib/impure/db_mysql.nim +++ b/lib/impure/db_mysql.nim @@ -1,14 +1,25 @@ -# Nimrod mySQL database wrapper -# (c) 2009 Andreas Rumpf +# +# +# Nimrod's Runtime Library +# (c) Copyright 2010 Andreas Rumpf +# +# See the file "copying.txt", included in this +# distribution, for details about the copyright. +# + +## A higher level `mySQL`:idx: database wrapper. The same interface is +## implemented for other databases too. import strutils, mysql type - TDbHandle* = PMySQL - TRow* = seq[string] - EDb* = object of EIO - -proc dbError(db: TDbHandle) {.noreturn.} = + TDbConn* = PMySQL ## encapsulates a database connection + TRow* = seq[string] ## a row of a dataset + EDb* = object of EIO ## exception that is raised if a database error occurs + + TSqlQuery* = distinct string ## an SQL query string + +proc dbError(db: TDbConn) {.noreturn.} = ## raises an EDb exception. var e: ref EDb new(e) @@ -23,13 +34,13 @@ proc dbError*(msg: string) {.noreturn.} = raise e when false: - proc dbQueryOpt*(db: TDbHandle, query: string, args: openarray[string]) = + proc dbQueryOpt*(db: TDbConn, query: string, args: openarray[string]) = var stmt = mysql_stmt_init(db) if stmt == nil: dbError(db) if mysql_stmt_prepare(stmt, query, len(query)) != 0: dbError(db) var - bind: seq[MYSQL_BIND] + binding: seq[MYSQL_BIND] discard mysql_stmt_close(stmt) proc dbQuote(s: string): string = @@ -49,33 +60,16 @@ proc dbFormat(formatstr: string, args: openarray[string]): string = else: add(result, c) -proc dbTryQuery*(db: TDbHandle, query: string, args: openarray[string]): bool = +proc TryQuery*(db: TDbConn, query: string, args: openarray[string]): bool = + ## tries to execute the query and returns true if successful, false otherwise. var q = dbFormat(query, args) return mysqlRealQuery(db, q, q.len) == 0'i32 -proc dbQuery*(db: TDbHandle, query: string, args: openarray[string]) = +proc Query*(db: TDbConn, query: string, args: openarray[string]) = + ## executes the query and raises EDB if not successful. var q = dbFormat(query, args) if mysqlRealQuery(db, q, q.len) != 0'i32: dbError(db) - -proc dbTryInsertID*(db: TDbHandle, query: string, - args: openarray[string]): int64 = - var q = dbFormat(query, args) - if mysqlRealQuery(db, q, q.len) != 0'i32: - result = -1'i64 - else: - result = mysql_insert_id(db) - -proc dbInsertID*(db: TDbHandle, query: string, args: openArray[string]): int64 = - result = dbTryInsertID(db, query, args) - if result < 0: dbError(db) - -proc dbQueryAffectedRows*(db: TDbHandle, query: string, - args: openArray[string]): int64 = - ## runs the query (typically "UPDATE") and returns the - ## number of affected rows - dbQuery(db, query, args) - result = mysql_affected_rows(db) - + proc newRow(L: int): TRow = newSeq(result, L) for i in 0..L-1: result[i] = "" @@ -84,11 +78,32 @@ proc properFreeResult(sqlres: PMYSQL_RES, row: cstringArray) = if row != nil: while mysqlFetchRow(sqlres) != nil: nil mysqlFreeResult(sqlres) + +iterator FastRows*(db: TDbConn, query: string, + args: openarray[string]): TRow = + ## executes the query and iterates over the result dataset. This is very + ## fast, but potenially dangerous: If the for-loop-body executes another + ## query, the results can be undefined. For Postgres it is safe though. + Query(db, query, args) + var sqlres = mysqlUseResult(db) + if sqlres != nil: + var L = int(mysql_num_fields(sqlres)) + var result = newRow(L) + var row: cstringArray + while true: + row = mysqlFetchRow(sqlres) + if row == nil: break + for i in 0..L-1: + setLen(result[i], 0) + add(result[i], row[i]) + yield result + properFreeResult(sqlres, row) -proc dbGetAllRows*(db: TDbHandle, query: string, - args: openarray[string]): seq[TRow] = +proc GetAllRows*(db: TDbConn, query: string, + args: openarray[string]): seq[TRow] = + ## executes the query and returns the whole result dataset. result = @[] - dbQuery(db, query, args) + Query(db, query, args) var sqlres = mysqlUseResult(db) if sqlres != nil: var L = int(mysql_num_fields(sqlres)) @@ -103,43 +118,56 @@ proc dbGetAllRows*(db: TDbHandle, query: string, inc(j) mysqlFreeResult(sqlres) -iterator dbRows*(db: TDbHandle, query: string, - args: openarray[string]): TRow = - for r in items(dbGetAllRows(db, query, args)): yield r - -iterator dbFastRows*(db: TDbHandle, query: string, - args: openarray[string]): TRow = - # this is carefully optimized, so that the memory is reused! - dbQuery(db, query, args) - var sqlres = mysqlUseResult(db) - if sqlres != nil: - var L = int(mysql_num_fields(sqlres)) - var result = newRow(L) - var row: cstringArray - while true: - row = mysqlFetchRow(sqlres) - if row == nil: break - for i in 0..L-1: - setLen(result[i], 0) - add(result[i], row[i]) - yield result - properFreeResult(sqlres, row) +iterator Rows*(db: TDbConn, query: string, + args: openarray[string]): TRow = + ## same as `FastRows`, but slower and safe. + for r in items(GetAllRows(db, query, args)): yield r -proc dbGetValue*(db: TDbHandle, query: string, - args: openarray[string]): string = +proc GetValue*(db: TDbConn, query: string, + args: openarray[string]): string = + ## executes the query and returns the result dataset's the first column + ## of the first row. Returns "" if the dataset contains no rows. This uses + ## `FastRows`, so it inherits its fragile behaviour. result = "" - for row in dbFastRows(db, query, args): + for row in FastRows(db, query, args): result = row[0] break -proc dbClose*(db: TDbHandle) = +proc TryInsertID*(db: TDbConn, query: string, + args: openarray[string]): int64 = + ## executes the query (typically "INSERT") and returns the + ## generated ID for the row or -1 in case of an error. + var q = dbFormat(query, args) + if mysqlRealQuery(db, q, q.len) != 0'i32: + result = -1'i64 + else: + result = mysql_insert_id(db) + +proc InsertID*(db: TDbConn, query: string, args: openArray[string]): int64 = + ## executes the query (typically "INSERT") and returns the + ## generated ID for the row. + result = TryInsertID(db, query, args) + if result < 0: dbError(db) + +proc QueryAffectedRows*(db: TDbConn, query: string, + args: openArray[string]): int64 = + ## runs the query (typically "UPDATE") and returns the + ## number of affected rows + Query(db, query, args) + result = mysql_affected_rows(db) + +proc Close*(db: TDbConn) = + ## closes the database connection. if db != nil: mysqlClose(db) -proc dbOpen*(connection, user, password, database: string): TDbHandle = +proc Open*(connection, user, password, database: string): TDbConn = + ## opens a database connection. Raises `EDb` if the connection could not + ## be established. result = mysqlInit(nil) - if result != nil: - if mysqlRealConnect(result, "", user, password, database, - 0'i32, nil, 0) == nil: - dbClose(result) - result = nil + if result == nil: dbError("could not open database connection") + if mysqlRealConnect(result, "", user, password, database, + 0'i32, nil, 0) == nil: + var errmsg = $mysql_error(result) + Close(result) + dbError(errmsg) |