diff options
| -rw-r--r-- | lib/impure/db_mysql.nim | 27 | ||||
| -rw-r--r-- | lib/impure/db_postgres.nim | 21 | ||||
| -rw-r--r-- | lib/impure/db_sqlite.nim | 24 |
3 files changed, 71 insertions, 1 deletions
diff --git a/lib/impure/db_mysql.nim b/lib/impure/db_mysql.nim index 619c2a656..7c2901efd 100644 --- a/lib/impure/db_mysql.nim +++ b/lib/impure/db_mysql.nim @@ -16,6 +16,9 @@ type DbConn* = PMySQL ## encapsulates a database connection Row* = seq[string] ## a row of a dataset. NULL database values will be ## transformed always to the empty string. + InstantRow* = tuple[row: cstringArray, len: int] ## 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 SqlQuery* = distinct string ## an SQL query string @@ -127,6 +130,30 @@ iterator fastRows*(db: DbConn, query: SqlQuery, yield result properFreeResult(sqlres, row) +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. + rawExec(db, query, args) + var sqlres = mysql.useResult(db) + if sqlres != nil: + let L = int(mysql.numFields(sqlres)) + var row: cstringArray + while true: + row = mysql.fetchRow(sqlres) + if row == nil: break + yield (row: row, len: L) + properFreeResult(sqlres, row) + +proc `[]`*(row: InstantRow, col: int): string {.inline.} = + ## returns text for given column of the row + $row.row[col] + +proc len*(row: InstantRow): int {.inline.} = + ## returns number of columns in the row + row.len + proc getRow*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]): Row {.tags: [FReadDB].} = ## retrieves a single row. If the query doesn't return any rows, this proc diff --git a/lib/impure/db_postgres.nim b/lib/impure/db_postgres.nim index 774cb1510..c88e660f4 100644 --- a/lib/impure/db_postgres.nim +++ b/lib/impure/db_postgres.nim @@ -16,6 +16,9 @@ type DbConn* = PPGconn ## encapsulates a database connection Row* = seq[string] ## a row of a dataset. NULL database values will be ## transformed always to the empty string. + InstantRow* = tuple[res: PPGresult, line: int32] ## 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 SqlQuery* = distinct string ## an SQL query string @@ -159,6 +162,24 @@ iterator fastRows*(db: DbConn, stmtName: SqlPrepared, yield result pqClear(res) +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 res = setupQuery(db, query, args) + for i in 0..pqNtuples(res)-1: + yield (res: res, line: i) + pqClear(res) + +proc `[]`*(row: InstantRow, col: int32): string {.inline.} = + ## returns text for given column of the row + $pqgetvalue(row.res, row.line, col) + +proc len*(row: InstantRow): int32 {.inline.} = + ## returns number of columns in the row + pqNfields(row.res) + proc getRow*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]): Row {.tags: [FReadDB].} = ## retrieves a single row. If the query doesn't return any rows, this proc diff --git a/lib/impure/db_sqlite.nim b/lib/impure/db_sqlite.nim index 47e7c1900..1a037becc 100644 --- a/lib/impure/db_sqlite.nim +++ b/lib/impure/db_sqlite.nim @@ -16,6 +16,8 @@ type 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 SqlQuery* = distinct string ## an SQL query string @@ -109,6 +111,24 @@ iterator fastRows*(db: DbConn, query: SqlQuery, yield result if finalize(stmt) != SQLITE_OK: dbError(db) +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 @@ -216,5 +236,7 @@ when not defined(testing) and 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) |