diff options
Diffstat (limited to 'lib/impure/db_sqlite.nim')
| -rw-r--r-- | lib/impure/db_sqlite.nim | 87 |
1 files changed, 55 insertions, 32 deletions
diff --git a/lib/impure/db_sqlite.nim b/lib/impure/db_sqlite.nim index 4be692f39..1a037becc 100644 --- a/lib/impure/db_sqlite.nim +++ b/lib/impure/db_sqlite.nim @@ -13,27 +13,30 @@ import strutils, sqlite3 type - TDbConn* = PSqlite3 ## encapsulates a database connection - TRow* = seq[string] ## a row of a dataset. NULL database values will be + DbConn* = PSqlite3 ## encapsulates a database connection + Row* = seq[string] ## a row of a dataset. NULL database values will be ## transformed always to the empty string. + InstantRow* = Pstmt ## a handle that can be used to get a row's column + ## text on demand EDb* = object of IOError ## exception that is raised if a database error occurs - TSqlQuery* = distinct string ## an SQL query string + SqlQuery* = distinct string ## an SQL query string FDb* = object of IOEffect ## effect that denotes a database operation FReadDb* = object of FDb ## effect that denotes a read operation FWriteDb* = object of FDb ## effect that denotes a write operation +{.deprecated: [TRow: Row, TSqlQuery: SqlQuery, TDbConn: DbConn].} -proc sql*(query: string): TSqlQuery {.noSideEffect, inline.} = - ## constructs a TSqlQuery from the string `query`. This is supposed to be +proc sql*(query: string): SqlQuery {.noSideEffect, inline.} = + ## constructs a SqlQuery from the string `query`. This is supposed to be ## used as a raw-string-literal modifier: ## ``sql"update user set counter = counter + 1"`` ## ## If assertions are turned off, it does nothing. If assertions are turned ## on, later versions will check the string for valid syntax. - result = TSqlQuery(query) + result = SqlQuery(query) -proc dbError(db: TDbConn) {.noreturn.} = +proc dbError(db: DbConn) {.noreturn.} = ## raises an EDb exception. var e: ref EDb new(e) @@ -55,7 +58,7 @@ proc dbQuote(s: string): string = else: add(result, c) add(result, '\'') -proc dbFormat(formatstr: TSqlQuery, args: varargs[string]): string = +proc dbFormat(formatstr: SqlQuery, args: varargs[string]): string = result = "" var a = 0 for c in items(string(formatstr)): @@ -65,7 +68,7 @@ proc dbFormat(formatstr: TSqlQuery, args: varargs[string]): string = else: add(result, c) -proc tryExec*(db: TDbConn, query: TSqlQuery, +proc tryExec*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]): bool {.tags: [FReadDb, FWriteDb].} = ## tries to execute the query and returns true if successful, false otherwise. var q = dbFormat(query, args) @@ -74,29 +77,29 @@ proc tryExec*(db: TDbConn, query: TSqlQuery, if step(stmt) == SQLITE_DONE: result = finalize(stmt) == SQLITE_OK -proc exec*(db: TDbConn, query: TSqlQuery, args: varargs[string, `$`]) {. +proc exec*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]) {. tags: [FReadDb, FWriteDb].} = ## executes the query and raises EDB if not successful. if not tryExec(db, query, args): dbError(db) -proc newRow(L: int): TRow = +proc newRow(L: int): Row = newSeq(result, L) for i in 0..L-1: result[i] = "" -proc setupQuery(db: TDbConn, query: TSqlQuery, +proc setupQuery(db: DbConn, query: SqlQuery, args: varargs[string]): Pstmt = var q = dbFormat(query, args) if prepare_v2(db, q, q.len.cint, result, nil) != SQLITE_OK: dbError(db) -proc setRow(stmt: Pstmt, r: var TRow, cols: cint) = +proc setRow(stmt: Pstmt, r: var Row, cols: cint) = for col in 0..cols-1: setLen(r[col], column_bytes(stmt, col)) # set capacity setLen(r[col], 0) let x = column_text(stmt, col) if not isNil(x): add(r[col], x) -iterator fastRows*(db: TDbConn, query: TSqlQuery, - args: varargs[string, `$`]): TRow {.tags: [FReadDb].} = +iterator fastRows*(db: DbConn, query: SqlQuery, + args: varargs[string, `$`]): Row {.tags: [FReadDb].} = ## executes the query and iterates over the result dataset. This is very ## fast, but potenially dangerous: If the for-loop-body executes another ## query, the results can be undefined. For Sqlite it is safe though. @@ -108,10 +111,28 @@ iterator fastRows*(db: TDbConn, query: TSqlQuery, yield result if finalize(stmt) != SQLITE_OK: dbError(db) -proc getRow*(db: TDbConn, query: TSqlQuery, - args: varargs[string, `$`]): TRow {.tags: [FReadDb].} = +iterator instantRows*(db: DbConn, query: SqlQuery, + args: varargs[string, `$`]): InstantRow + {.tags: [FReadDb].} = + ## same as fastRows but returns a handle that can be used to get column text + ## on demand using []. Returned handle is valid only within interator body. + var stmt = setupQuery(db, query, args) + while step(stmt) == SQLITE_ROW: + yield stmt + if finalize(stmt) != SQLITE_OK: dbError(db) + +proc `[]`*(row: InstantRow, col: int32): string {.inline.} = + ## returns text for given column of the row + $column_text(row, col) + +proc len*(row: InstantRow): int32 {.inline.} = + ## returns number of columns in the row + column_count(row) + +proc getRow*(db: DbConn, query: SqlQuery, + args: varargs[string, `$`]): Row {.tags: [FReadDb].} = ## retrieves a single row. If the query doesn't return any rows, this proc - ## will return a TRow with empty strings for each column. + ## will return a Row with empty strings for each column. var stmt = setupQuery(db, query, args) var L = (column_count(stmt)) result = newRow(L) @@ -119,19 +140,19 @@ proc getRow*(db: TDbConn, query: TSqlQuery, setRow(stmt, result, L) if finalize(stmt) != SQLITE_OK: dbError(db) -proc getAllRows*(db: TDbConn, query: TSqlQuery, - args: varargs[string, `$`]): seq[TRow] {.tags: [FReadDb].} = +proc getAllRows*(db: DbConn, query: SqlQuery, + args: varargs[string, `$`]): seq[Row] {.tags: [FReadDb].} = ## executes the query and returns the whole result dataset. result = @[] for r in fastRows(db, query, args): result.add(r) -iterator rows*(db: TDbConn, query: TSqlQuery, - args: varargs[string, `$`]): TRow {.tags: [FReadDb].} = +iterator rows*(db: DbConn, query: SqlQuery, + args: varargs[string, `$`]): Row {.tags: [FReadDb].} = ## same as `FastRows`, but slower and safe. for r in fastRows(db, query, args): yield r -proc getValue*(db: TDbConn, query: TSqlQuery, +proc getValue*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]): string {.tags: [FReadDb].} = ## executes the query and returns the first column of the first row of the ## result dataset. Returns "" if the dataset contains no rows or the database @@ -148,7 +169,7 @@ proc getValue*(db: TDbConn, query: TSqlQuery, result = "" if finalize(stmt) != SQLITE_OK: dbError(db) -proc tryInsertID*(db: TDbConn, query: TSqlQuery, +proc tryInsertID*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]): int64 {.tags: [FWriteDb], raises: [].} = ## executes the query (typically "INSERT") and returns the @@ -162,7 +183,7 @@ proc tryInsertID*(db: TDbConn, query: TSqlQuery, if finalize(stmt) != SQLITE_OK: result = -1 -proc insertID*(db: TDbConn, query: TSqlQuery, +proc insertID*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]): int64 {.tags: [FWriteDb].} = ## executes the query (typically "INSERT") and returns the ## generated ID for the row. For Postgre this adds @@ -171,7 +192,7 @@ proc insertID*(db: TDbConn, query: TSqlQuery, result = tryInsertID(db, query, args) if result < 0: dbError(db) -proc execAffectedRows*(db: TDbConn, query: TSqlQuery, +proc execAffectedRows*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]): int64 {. tags: [FReadDb, FWriteDb].} = ## executes the query (typically "UPDATE") and returns the @@ -179,21 +200,21 @@ proc execAffectedRows*(db: TDbConn, query: TSqlQuery, exec(db, query, args) result = changes(db) -proc close*(db: TDbConn) {.tags: [FDb].} = +proc close*(db: DbConn) {.tags: [FDb].} = ## closes the database connection. if sqlite3.close(db) != SQLITE_OK: dbError(db) -proc open*(connection, user, password, database: string): TDbConn {. +proc open*(connection, user, password, database: string): DbConn {. tags: [FDb].} = ## opens a database connection. Raises `EDb` if the connection could not ## be established. Only the ``connection`` parameter is used for ``sqlite``. - var db: TDbConn + var db: DbConn if sqlite3.open(connection, db) == SQLITE_OK: result = db else: dbError(db) -proc setEncoding*(connection: TDbConn, encoding: string): bool {. +proc setEncoding*(connection: DbConn, encoding: string): bool {. tags: [FDb].} = ## sets the encoding of a database connection, returns true for ## success, false for failure. @@ -205,7 +226,7 @@ proc setEncoding*(connection: TDbConn, encoding: string): bool {. exec(connection, sql"PRAGMA encoding = ?", [encoding]) result = connection.getValue(sql"PRAGMA encoding") == encoding -when isMainModule: +when not defined(testing) and isMainModule: var db = open("db.sql", "", "", "") exec(db, sql"create table tbl1(one varchar(10), two smallint)", []) exec(db, sql"insert into tbl1 values('hello!',10)", []) @@ -215,5 +236,7 @@ when isMainModule: #db.query("insert into tbl1 values('goodbye', 20)") for r in db.rows(sql"select * from tbl1", []): echo(r[0], r[1]) - + for r in db.instantRows(sql"select * from tbl1", []): + echo(r[0], r[1]) + db_sqlite.close(db) |