A higher level mySQL database wrapper. The same interface is implemented for other databases too.
Example:
import db_mysql, math let theDb = open("localhost", "nim", "nim", "test") theDb.exec(sql"Drop table if exists myTestTbl") theDb.exec(sql("create table myTestTbl (" & " Id INT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY, " & " Name VARCHAR(50) NOT NULL, " & " i INT(11), " & " f DECIMAL(18,10))")) theDb.exec(sql"START TRANSACTION") for i in 1..1000: theDb.exec(sql"INSERT INTO myTestTbl (name,i,f) VALUES (?,?,?)", "Item#" & $i, i, sqrt(i.float)) theDb.exec(sql"COMMIT") for x in theDb.fastRows(sql"select * from myTestTbl"): echo x let id = theDb.tryInsertId(sql"INSERT INTO myTestTbl (name,i,f) VALUES (?,?,?)", "Item#1001", 1001, sqrt(1001.0)) echo "Inserted item: ", theDb.getValue(sql"SELECT name FROM myTestTbl WHERE id=?", id) theDb.close()
Types
DbConn = PMySQL
- encapsulates a database connection Source
Row = seq[string]
- a row of a dataset. NULL database values will be transformed always to the empty string. Source
InstantRow = tuple[row: cstringArray, len: int]
- a handle that can be used to get a row's column text on demand Source
EDb = object of IOError
- exception that is raised if a database error occurs Source
SqlQuery = distinct string
- an SQL query string Source
FDb = object of IOEffect
- effect that denotes a database operation Source
FReadDb = object of FDb
- effect that denotes a read operation Source
FWriteDb = object of FDb
- effect that denotes a write operation Source
Procs
proc sql(query: string): SqlQuery {.noSideEffect, inline, raises: [], tags: [].}
-
constructs a SqlQuery from the string query. This is supposed to be used as a raw-string-literal modifier: sql"update user set counter = counter + 1"
If assertions are turned off, it does nothing. If assertions are turned on, later versions will check the string for valid syntax.
Source proc dbError(msg: string) {.noreturn, raises: [EDb], tags: [].}
- raises an EDb exception with message msg. Source
proc dbQuote(s: string): string {.raises: [], tags: [].}
- DB quotes the string. Source
proc tryExec(db: DbConn; query: SqlQuery; args: varargs[string, `$`]): bool {. tags: [FReadDb, FWriteDb], raises: [].}
- tries to execute the query and returns true if successful, false otherwise. Source
proc exec(db: DbConn; query: SqlQuery; args: varargs[string, `$`]) {. tags: [FReadDb, FWriteDb], raises: [EDb].}
- executes the query and raises EDB if not successful. Source
proc `[]`(row: InstantRow; col: int): string {.inline, raises: [], tags: [].}
- returns text for given column of the row Source
proc len(row: InstantRow): int {.inline, raises: [], tags: [].}
- returns number of columns in the row Source
proc getRow(db: DbConn; query: SqlQuery; args: varargs[string, `$`]): Row {. tags: [FReadDb], raises: [EDb].}
- retrieves a single row. If the query doesn't return any rows, this proc will return a Row with empty strings for each column. Source
proc getAllRows(db: DbConn; query: SqlQuery; args: varargs[string, `$`]): seq[Row] {. tags: [FReadDb], raises: [EDb].}
- executes the query and returns the whole result dataset. Source
proc getValue(db: DbConn; query: SqlQuery; args: varargs[string, `$`]): string {. tags: [FReadDb], raises: [EDb].}
- 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 value is NULL. Source
proc tryInsertId(db: DbConn; query: SqlQuery; args: varargs[string, `$`]): int64 {. tags: [FWriteDb], raises: [].}
- executes the query (typically "INSERT") and returns the generated ID for the row or -1 in case of an error. Source
proc insertId(db: DbConn; query: SqlQuery; args: varargs[string, `$`]): int64 {. tags: [FWriteDb], raises: [EDb].}
- executes the query (typically "INSERT") and returns the generated ID for the row. Source
proc execAffectedRows(db: DbConn; query: SqlQuery; args: varargs[string, `$`]): int64 {. tags: [FReadDb, FWriteDb], raises: [EDb].}
- runs the query (typically "UPDATE") and returns the number of affected rows Source
proc close(db: DbConn) {.tags: [FDb], raises: [].}
- closes the database connection. Source
proc open(connection, user, password, database: string): DbConn {.tags: [FDb], raises: [EDb, OverflowError, ValueError].}
- opens a database connection. Raises EDb if the connection could not be established. Source
proc setEncoding(connection: DbConn; encoding: string): bool {.tags: [FDb], raises: [].}
- sets the encoding of a database connection, returns true for success, false for failure. Source
Iterators
iterator fastRows(db: DbConn; query: SqlQuery; args: varargs[string, `$`]): Row {. tags: [FReadDb], raises: [EDb].}
-
executes the query and iterates over the result dataset.
This is very fast, but potentially dangerous. Use this iterator only if you require ALL the rows.
Breaking the fastRows() iterator during a loop will cause the next database query to raise an [EDb] exception Commands out of sync.
Source iterator instantRows(db: DbConn; query: SqlQuery; args: varargs[string, `$`]): InstantRow {. tags: [FReadDb], raises: [EDb].}
- same as fastRows but returns a handle that can be used to get column text on demand using []. Returned handle is valid only within the interator body. Source
iterator rows(db: DbConn; query: SqlQuery; args: varargs[string, `$`]): Row {. tags: [FReadDb], raises: [EDb].}
- same as fastRows, but slower and safe. Source