Safe Haskell	None
Language	Haskell2010

Database.SQLite3.Direct

Contents

Connection management
Simple query execution
Statement management
Parameter and column information
Binding values to a prepared statement
Reading the result row
control loading of extensions
Result statistics
Create custom SQL functions
- Extract function arguments
- Set the result of a function
Create custom collations
Interrupting a long-running query
Types
- Results and errors
- Special types

Description

This API is a slightly lower-level version of Database.SQLite3. Namely:

It returns errors instead of throwing them.
It only uses cheap conversions. None of these bindings convert from String or Text.

Synopsis

Connection management

open :: Utf8 -> IO (Either (Error, Utf8) Database) Source

http://www.sqlite.org/c3ref/open.html

close :: Database -> IO (Either Error ()) Source

http://www.sqlite.org/c3ref/close.html

errmsg :: Database -> IO Utf8 Source

http://www.sqlite.org/c3ref/errcode.html

setTrace :: Database -> Maybe (Utf8 -> IO ()) -> IO () Source

http://www.sqlite.org/c3ref/profile.html

Enable/disable tracing of SQL execution. Tracing can be disabled by setting Nothing as the logger callback.

Warning: If the logger callback throws an exception, your whole program will crash. Enable only for debugging!

getAutoCommit :: Database -> IO Bool Source

http://www.sqlite.org/c3ref/get_autocommit.html

Return True if the connection is in autocommit mode, or False if a transaction started with BEGIN is still active.

Be warned that some errors roll back the transaction automatically, and that ROLLBACK will throw an error if no transaction is active. Use getAutoCommit to avoid such an error:

 autocommit <- getAutoCommit conn
 when (not autocommit) $
     exec conn "ROLLBACK"

Simple query execution

http://sqlite.org/c3ref/exec.html

exec :: Database -> Utf8 -> IO (Either (Error, Utf8) ()) Source

execWithCallback :: Database -> Utf8 -> ExecCallback -> IO (Either (Error, Utf8) ()) Source

Like exec, but invoke the callback for each result row.

If the callback throws an exception, it will be rethrown by execWithCallback.

type ExecCallback Source

Arguments

= ColumnCount	Number of columns, which is the number of items in the following lists. This will be the same for every row.
-> [Utf8]	List of column names. This will be the same for every row.
-> [Maybe Utf8]	List of column values, as returned by `columnText`.
-> IO ()

Statement management

prepare :: Database -> Utf8 -> IO (Either Error (Maybe Statement)) Source

http://www.sqlite.org/c3ref/prepare.html

If the query contains no SQL statements, this returns Right Nothing.

getStatementDatabase :: Statement -> IO Database Source

http://www.sqlite.org/c3ref/db_handle.html

step :: Statement -> IO (Either Error StepResult) Source

http://www.sqlite.org/c3ref/step.html

reset :: Statement -> IO (Either Error ()) Source

http://www.sqlite.org/c3ref/reset.html

Warning:

If the most recent step call failed, this will return the corresponding error.
This does not reset the bindings on a prepared statement. Use clearBindings to do that.

finalize :: Statement -> IO (Either Error ()) Source

http://www.sqlite.org/c3ref/finalize.html

Warning: If the most recent step call failed, this will return the corresponding error.

clearBindings :: Statement -> IO () Source

http://www.sqlite.org/c3ref/clear_bindings.html

Set all parameters in the prepared statement to null.

statementSql :: Statement -> IO (Maybe Utf8) Source

http://www.sqlite.org/c3ref/sql.html

Return a copy of the original SQL text used to compile the statement.

Parameter and column information

bindParameterCount :: Statement -> IO ParamIndex Source

http://www.sqlite.org/c3ref/bind_parameter_count.html

This returns the index of the largest (rightmost) parameter. Note that this is not necessarily the number of parameters. If numbered parameters like ?5 are used, there may be gaps in the list.

See ParamIndex for more information.

bindParameterName :: Statement -> ParamIndex -> IO (Maybe Utf8) Source

http://www.sqlite.org/c3ref/bind_parameter_name.html

bindParameterIndex :: Statement -> Utf8 -> IO (Maybe ParamIndex) Source

http://www.sqlite.org/c3ref/bind_parameter_index.html

columnCount :: Statement -> IO ColumnCount Source

http://www.sqlite.org/c3ref/column_count.html

columnName :: Statement -> ColumnIndex -> IO (Maybe Utf8) Source

http://www.sqlite.org/c3ref/column_name.html

Binding values to a prepared statement

http://www.sqlite.org/c3ref/bind_blob.html

bindInt64 :: Statement -> ParamIndex -> Int64 -> IO (Either Error ()) Source

bindDouble :: Statement -> ParamIndex -> Double -> IO (Either Error ()) Source

bindText :: Statement -> ParamIndex -> Utf8 -> IO (Either Error ()) Source

bindBlob :: Statement -> ParamIndex -> ByteString -> IO (Either Error ()) Source

bindNull :: Statement -> ParamIndex -> IO (Either Error ()) Source

Reading the result row

http://www.sqlite.org/c3ref/column_blob.html

columnType :: Statement -> ColumnIndex -> IO ColumnType Source

columnInt64 :: Statement -> ColumnIndex -> IO Int64 Source

columnDouble :: Statement -> ColumnIndex -> IO Double Source

columnText :: Statement -> ColumnIndex -> IO Utf8 Source

columnBlob :: Statement -> ColumnIndex -> IO ByteString Source

control loading of extensions

setLoadExtensionEnabled :: Database -> Bool -> IO (Either Error ()) Source

http://www.sqlite.org/c3ref/enable_load_extension.html

Enable or disable extension loading.

Result statistics

lastInsertRowId :: Database -> IO Int64 Source

http://www.sqlite.org/c3ref/last_insert_rowid.html

changes :: Database -> IO Int Source

http://www.sqlite.org/c3ref/changes.html

Return the number of rows that were changed, inserted, or deleted by the most recent INSERT, DELETE, or UPDATE statement.

totalChanges :: Database -> IO Int Source

http://www.sqlite.org/c3ref/total_changes.html

Return the total number of row changes caused by INSERT, DELETE, or UPDATE statements since the Database was opened.

Create custom SQL functions

createFunction Source

Arguments

:: Database
-> Utf8	Name of the function.
-> Maybe ArgCount	Number of arguments. `Nothing` means that the function accepts any number of arguments.
-> Bool	Is the function deterministic?
-> (FuncContext -> FuncArgs -> IO ())	Implementation of the function.
-> IO (Either Error ())

http://sqlite.org/c3ref/create_function.html

Create a custom SQL function or redefine the behavior of an existing function.

createAggregate Source

Arguments

:: Database
-> Utf8	Name of the function.
-> Maybe ArgCount	Number of arguments.
-> a	Initial aggregate state.
-> (FuncContext -> FuncArgs -> a -> IO a)	Process one row and update the aggregate state.
-> (FuncContext -> a -> IO ())	Called after all rows have been processed. Can be used to construct the returned value from the aggregate state.
-> IO (Either Error ())

Like createFunction except that it creates an aggregate function.

deleteFunction :: Database -> Utf8 -> Maybe ArgCount -> IO (Either Error ()) Source

Delete an SQL function (scalar or aggregate).

Extract function arguments

funcArgCount :: FuncArgs -> ArgCount Source

funcArgType :: FuncArgs -> ArgIndex -> IO ColumnType Source

funcArgInt64 :: FuncArgs -> ArgIndex -> IO Int64 Source

funcArgDouble :: FuncArgs -> ArgIndex -> IO Double Source

funcArgText :: FuncArgs -> ArgIndex -> IO Utf8 Source

funcArgBlob :: FuncArgs -> ArgIndex -> IO ByteString Source

Set the result of a function

funcResultInt64 :: FuncContext -> Int64 -> IO () Source

funcResultDouble :: FuncContext -> Double -> IO () Source

funcResultText :: FuncContext -> Utf8 -> IO () Source

funcResultBlob :: FuncContext -> ByteString -> IO () Source

funcResultNull :: FuncContext -> IO () Source

Create custom collations

createCollation Source

Arguments

:: Database
-> Utf8	Name of the collation.
-> (Utf8 -> Utf8 -> Ordering)	Comparison function.
-> IO (Either Error ())

http://www.sqlite.org/c3ref/create_collation.html

deleteCollation :: Database -> Utf8 -> IO (Either Error ()) Source

Delete a collation.

Interrupting a long-running query

interrupt :: Database -> IO () Source

http://www.sqlite.org/c3ref/interrupt.html

Cause any pending operation on the Database handle to stop at its earliest opportunity. This simply sets a flag and returns immediately. It does not wait for the pending operation to finish.

You'll need to compile with -threaded for this to do any good. Without -threaded, FFI calls block the whole RTS, meaning interrupt would never run at the same time as step.

Types

newtype Database Source

Constructors

Database (Ptr CDatabase)

Instances

Eq Database
Show Database

newtype Statement Source

Constructors

Statement (Ptr CStatement)

Instances

Eq Statement
Show Statement

data ColumnType Source

Constructors

IntegerColumn
FloatColumn
TextColumn
BlobColumn
NullColumn

Instances

Eq ColumnType
Show ColumnType
FFIType ColumnType CColumnType

newtype FuncContext Source

The context in which a custom SQL function is executed.

Constructors

FuncContext (Ptr CContext)

Instances

Eq FuncContext
Show FuncContext

data FuncArgs Source

The arguments of a custom SQL function.

Constructors

FuncArgs CArgCount (Ptr (Ptr CValue))

Results and errors

data StepResult Source

Constructors

Row
Done

Instances

Eq StepResult
Show StepResult

data Error Source

Constructors

ErrorOK	Successful result
ErrorError	SQL error or missing database
ErrorInternal	Internal logic error in SQLite
ErrorPermission	Access permission denied
ErrorAbort	Callback routine requested an abort
ErrorBusy	The database file is locked
ErrorLocked	A table in the database is locked
ErrorNoMemory	A `malloc()` failed
ErrorReadOnly	Attempt to write a readonly database
ErrorInterrupt	Operation terminated by `sqlite3_interrupt()`
ErrorIO	Some kind of disk I/O error occurred
ErrorCorrupt	The database disk image is malformed
ErrorNotFound	Unknown opcode in `sqlite3_file_control()`
ErrorFull	Insertion failed because database is full
ErrorCan'tOpen	Unable to open the database file
ErrorProtocol	Database lock protocol error
ErrorEmpty	Database is empty
ErrorSchema	The database schema changed
ErrorTooBig	String or BLOB exceeds size limit
ErrorConstraint	Abort due to constraint violation
ErrorMismatch	Data type mismatch
ErrorMisuse	Library used incorrectly
ErrorNoLargeFileSupport	Uses OS features not supported on host
ErrorAuthorization	Authorization denied
ErrorFormat	Auxiliary database format error
ErrorRange	2nd parameter to sqlite3_bind out of range
ErrorNotADatabase	File opened that is not a database file
ErrorRow	`sqlite3_step()` has another row ready
ErrorDone	`sqlite3_step()` has finished executing

Instances

Eq Error
Show Error
FFIType Error CError

Special types

newtype Utf8 Source

A ByteString containing UTF8-encoded text with no NUL characters.

Constructors

Utf8 ByteString

Instances

Eq Utf8
Ord Utf8
Show Utf8
IsString Utf8	fromString = Utf8 . `encodeUtf8` . `pack`
Monoid Utf8

newtype ParamIndex Source

Index of a parameter in a parameterized query. Parameter indices start from 1.

When a query is prepared, SQLite allocates an array indexed from 1 to the highest parameter index. For example:

>Right stmt <- prepare conn "SELECT ?1, ?5, ?3, ?"
>bindParameterCount stmt
ParamIndex 6

This will allocate an array indexed from 1 to 6 (? takes the highest preceding index plus one). The array is initialized with null values. When you bind a parameter with bindSQLData, it assigns a new value to one of these indices.

See http://www.sqlite.org/lang_expr.html#varparam for the syntax of parameter placeholders, and how parameter indices are assigned.

Constructors

ParamIndex Int

Instances

Bounded ParamIndex	Limit min/max bounds to fit into SQLite's native parameter ranges.
Enum ParamIndex
Eq ParamIndex
Integral ParamIndex
Num ParamIndex
Ord ParamIndex
Real ParamIndex
Show ParamIndex	This just shows the underlying integer, without the data constructor.
FFIType ParamIndex CParamIndex

newtype ColumnIndex Source

Index of a column in a result set. Column indices start from 0.

Constructors

ColumnIndex Int

Instances

Bounded ColumnIndex	Limit min/max bounds to fit into SQLite's native parameter ranges.
Enum ColumnIndex
Eq ColumnIndex
Integral ColumnIndex
Num ColumnIndex
Ord ColumnIndex
Real ColumnIndex
Show ColumnIndex	This just shows the underlying integer, without the data constructor.
FFIType ColumnIndex CColumnIndex

type ColumnCount = ColumnIndex Source

Number of columns in a result set.

newtype ArgCount Source

Number of arguments of a user defined SQL function.

Constructors

ArgCount Int

Instances

Bounded ArgCount
Enum ArgCount
Eq ArgCount
Integral ArgCount
Num ArgCount
Ord ArgCount
Real ArgCount
Show ArgCount	This just shows the underlying integer, without the data constructor.
FFIType ArgCount CArgCount

type ArgIndex = ArgCount Source

Index of an argument to a custom function. Indices start from 0.