PostgreSqlDialect

BooleanCastSqlType

public override string BooleanCastSqlType { get; }

value = postgreSqlDialect.BooleanCastSqlType

SQL type name to cast a boolean expression to when materialising EXISTS(...) projections (e.g. bit on SQL Server). Return if the dialect represents booleans natively and no cast is needed (e.g. PostgreSQL).

ConcatOperator

public override string ConcatOperator { get; }

value = postgreSqlDialect.ConcatOperator

SQL string concatenation operator.

EmptyBinaryLiteral

public override string EmptyBinaryLiteral { get; }

value = postgreSqlDialect.EmptyBinaryLiteral

SQL literal for an empty binary value (e.g. 0x for SQL Server, X'' for the SQL standard, an empty bytea for PostgreSQL).

FalseLiteral

public override string FalseLiteral { get; }

value = postgreSqlDialect.FalseLiteral

SQL literal for boolean false.

IsNullFunction

public override string IsNullFunction { get; }

value = postgreSqlDialect.IsNullFunction

Function name for null-coalescing.

LenFunction

public override string LenFunction { get; }

value = postgreSqlDialect.LenFunction

Function name for string length.

MaxParameters

public override int MaxParameters { get; }

value = postgreSqlDialect.MaxParameters

Maximum number of parameters allowed in a single statement. SQL Server: 2100, SQLite: 999, PostgreSQL: 65535, MySQL: 65535.

ParameterPrefix

public override string ParameterPrefix { get; }

value = postgreSqlDialect.ParameterPrefix

Parameter prefix (e.g. @ for SQL Server, $ for PostgreSQL).

SupportsInsertReturning

public override bool SupportsInsertReturning { get; }

value = postgreSqlDialect.SupportsInsertReturning

True when this dialect can return a server-generated identity in the same statement via String); callers use it to choose between a single-statement INSERT…RETURNING and a two-statement INSERT + SELECT identity batch.

TrueLiteral

public override string TrueLiteral { get; }

value = postgreSqlDialect.TrueLiteral

SQL literal for boolean true.

UnicodePrefix

public override string UnicodePrefix { get; }

value = postgreSqlDialect.UnicodePrefix

Unicode string-literal prefix (e.g. N for SQL Server).

AppendAlterColumn

public override void AppendAlterColumn(StringBuilder sb, string tableName, string columnName, Type clrType, bool isNullable, int maxLength, int precision, int scale, DbColumnInfo live)

postgreSqlDialect.AppendAlterColumn(sb, tableName, columnName, clrType, isNullable, maxLength, precision, scale, live)

Appends ALTER TABLE ALTER COLUMN that gives a column the declared type and nullability.

sb

Where the statement goes.

tableName

The table.

columnName

The column.

clrType

The property type the column holds.

isNullable

Whether the column should allow NULLs.

maxLength

The declared length, 0 for the default.

precision

The declared precision, 0 for the default.

scale

The declared scale.

live

The column as the database holds it, or null for a column this script has just added; a dialect uses it to keep what the declaration does not decide, and to convert the stored values.

AppendAlterNullability

public override void AppendAlterNullability(StringBuilder sb, string tableName, string columnName, bool isNullable, DbColumnInfo live)

postgreSqlDialect.AppendAlterNullability(sb, tableName, columnName, isNullable, live)

Makes a column nullable or not, leaving its type as the database holds it.

sb

Where the statement goes.

tableName

The table.

columnName

The column.

isNullable

Whether the column should allow NULLs.

live

The column as the database holds it.

AppendCreateTable

public override void AppendCreateTable(StringBuilder sb, string tableName, string columnDefs)

postgreSqlDialect.AppendCreateTable(sb, tableName, columnDefs)

Appends CREATE TABLE [IF NOT EXISTS] statement.

AppendDateAdd

public override void AppendDateAdd(StringBuilder sb, string part, string amountSql, string sourceSql)

postgreSqlDialect.AppendDateAdd(sb, part, amountSql, sourceSql)

Appends a DATEADD-style expression.

AppendDateDiff

public override void AppendDateDiff(StringBuilder sb, string part, string startSql, string endSql)

postgreSqlDialect.AppendDateDiff(sb, part, startSql, endSql)

Appends a DATEDIFF-style expression computing minus , expressed in units.

sb

Target builder.

part

Unit of the result: year, month, week, day, hour, minute, second or millisecond.

startSql

SQL of the start date.

endSql

SQL of the end date.

AppendDatePartClose

public override void AppendDatePartClose(StringBuilder sb)

postgreSqlDialect.AppendDatePartClose(sb)

Closes a date-part extraction expression opened by String).

AppendDatePartOpen

public override void AppendDatePartOpen(StringBuilder sb, string part)

postgreSqlDialect.AppendDatePartOpen(sb, part)

Opens a date-part extraction expression (closed by StringBuilder)).

AppendDropTable

public override void AppendDropTable(StringBuilder sb, string tableName)

postgreSqlDialect.AppendDropTable(sb, tableName)

Appends DROP TABLE [IF EXISTS] statement.

AppendFallbackOrderBy

public override void AppendFallbackOrderBy(StringBuilder sb)

postgreSqlDialect.AppendFallbackOrderBy(sb)

Appends a fallback ORDER BY clause when there is neither explicit ordering nor an identity column. SQL Server requires ORDER BY for OFFSET/FETCH; other dialects may emit a deterministic shim or nothing at all.

AppendGreatest

public override void AppendGreatest(StringBuilder sb, string leftSql, string rightSql)

postgreSqlDialect.AppendGreatest(sb, leftSql, rightSql)

Appends the larger of two values, the way Decimal) picks it: a scalar function of two arguments, not the MAX aggregate.

sb

Target builder.

leftSql

SQL of the first value.

rightSql

SQL of the second value.

AppendInsertReturningClause

public override void AppendInsertReturningClause(StringBuilder sb, string idColumn)

postgreSqlDialect.AppendInsertReturningClause(sb, idColumn)

Appends a dialect-specific RETURNING clause to an INSERT, scoped to the given identity column. PostgreSQL emits RETURNING "Id"; SQL Server and SQLite have other identity-read mechanisms and emit nothing here.

AppendLeast

public override void AppendLeast(StringBuilder sb, string leftSql, string rightSql)

postgreSqlDialect.AppendLeast(sb, leftSql, rightSql)

Appends the smaller of two values, the way Decimal) picks it: a scalar function of two arguments, not the MIN aggregate.

sb

Target builder.

leftSql

SQL of the first value.

rightSql

SQL of the second value.

AppendPagination

public override void AppendPagination(StringBuilder sb, long? skip, long? take, bool hasOrderBy)

postgreSqlDialect.AppendPagination(sb, skip, take, hasOrderBy)

Appends literal pagination (LIMIT/OFFSET or OFFSET/FETCH) with values.

AppendPaginationParams

public override void AppendPaginationParams(StringBuilder sb, string skipParamExpr, string takeParamExpr)

postgreSqlDialect.AppendPaginationParams(sb, skipParamExpr, takeParamExpr)

Appends parameterised pagination with already-prefixed parameter expressions (e.g. @skip, @take).

AppendTrimClose

public override void AppendTrimClose(StringBuilder sb)

postgreSqlDialect.AppendTrimClose(sb)

Closes a TRIM expression opened by StringBuilder).

AppendTrimOpen

public override void AppendTrimOpen(StringBuilder sb)

postgreSqlDialect.AppendTrimOpen(sb)

Opens a TRIM expression (closed by StringBuilder)).

AppendTruncate

protected override void AppendTruncate(StringBuilder sb, string valueSql, string digitsSql)

postgreSqlDialect.AppendTruncate(sb, valueSql, digitsSql)

Appends an expression that drops the digits of a value beyond , rounding toward zero.

sb

Target builder.

valueSql

SQL of the value.

digitsSql

SQL of the number of fractional digits to keep, or for a whole number.

AppendUpsert

public override void AppendUpsert(StringBuilder sb, string tableName, string[] allColumns, string[] keyColumns)

postgreSqlDialect.AppendUpsert(sb, tableName, allColumns, keyColumns)

Appends a UPSERT statement (MERGE on SQL Server, INSERT … ON CONFLICT on PostgreSQL/SQLite).

FormatSkip

public override string FormatSkip(string skip)

result = postgreSqlDialect.FormatSkip(skip)

Renders a SKIP/OFFSET clause from a parameter expression.

FormatTake

public override string FormatTake(string take)

result = postgreSqlDialect.FormatTake(take)

Renders a TAKE/FETCH clause from a parameter expression.

GetColumnTypeName

public override string GetColumnTypeName(Type clrType, int maxLength, int precision, int scale)

result = postgreSqlDialect.GetColumnTypeName(clrType, maxLength, precision, scale)

The SQL type a column is created with: the type name together with its length, precision or scale. A decimal that declares only a scale gets DefaultDecimalPrecision; one that declares a precision keeps its scale as declared, zero included.

GetIdentityColumnSuffix

public override string GetIdentityColumnSuffix()

result = postgreSqlDialect.GetIdentityColumnSuffix()

Suffix for an identity (auto-increment primary key) column definition.

GetIdentitySelect

public override string GetIdentitySelect(string idCol)

result = postgreSqlDialect.GetIdentitySelect(idCol)

SQL expression that returns the identity value of the last insert.

GetSqlTypeName

public override string GetSqlTypeName(Type clrType)

result = postgreSqlDialect.GetSqlTypeName(clrType)

Returns the SQL type name for a CLR type.

GetSqlTypeName

public override string GetSqlTypeName(Type clrType, int maxLength)

result = postgreSqlDialect.GetSqlTypeName(clrType, maxLength)

Canonical SQL type name with length applied. Dialects override when the type differs by length (e.g. PostgreSQL TEXT vs VARCHAR(N)).

NewId

public override string NewId()

result = postgreSqlDialect.NewId()

Generates a new unique identifier.

NormalizeDbType

public override string NormalizeDbType(string dbTypeName)

result = postgreSqlDialect.NormalizeDbType(dbTypeName)

Normalises a raw database type name to the canonical form used by this dialect.

Now

public override string Now()

result = postgreSqlDialect.Now()

Current local date/time.

PrepareParameter

public override void PrepareParameter(DbParameter parameter)

postgreSqlDialect.PrepareParameter(parameter)

Final-stage massaging of a fully populated DbParameter before it leaves the ORM layer. Lets a dialect adjust provider-specific type metadata that the generic DbType hint can't express — e.g. PostgreSQL needs timestamptz binding for UTC-kind DateTime values, which only Npgsql's own NpgsqlDbType property can express. Default is a no-op.

QuoteIdentifier

public override string QuoteIdentifier(string identifier)

result = postgreSqlDialect.QuoteIdentifier(identifier)

Quotes an identifier (table name, column name).

ReadDbForeignKeysAsync

public override Task<IReadOnlyList<DbForeignKeyInfo>> ReadDbForeignKeysAsync(DbConnection connection, string tableSchema, CancellationToken cancellationToken)

result = postgreSqlDialect.ReadDbForeignKeysAsync(connection, tableSchema, cancellationToken)

Reads foreign-key metadata from a live database. Used by the schema migrator to detect missing/extra FK constraints on tables that already exist.

connection

An open database connection.

tableSchema

Schema name (e.g. "dbo" or "public"); dialect default when .

cancellationToken

Cancellation token.

返回值: One row per FK column — compound FKs surface as multiple rows.

ReadDbIndexesAsync

public override Task<IReadOnlyList<DbIndexInfo>> ReadDbIndexesAsync(DbConnection connection, string tableSchema, CancellationToken cancellationToken)

result = postgreSqlDialect.ReadDbIndexesAsync(connection, tableSchema, cancellationToken)

Reads index metadata from a live database. Used by the schema migrator to detect missing entity-declared [Index] / [Unique] attributes on tables that already exist. Composite indexes are returned as multiple rows sharing IndexName with ascending ColumnOrdinal.

connection

An open database connection.

tableSchema

Schema name (e.g. "dbo" or "public"); dialect default when .

cancellationToken

Cancellation token.

返回值: One row per indexed column — composite indexes surface as multiple rows.

ReadDbSchemaAsync

public override Task<IReadOnlyList<DbColumnInfo>> ReadDbSchemaAsync(DbConnection connection, string tableSchema, CancellationToken cancellationToken)

result = postgreSqlDialect.ReadDbSchemaAsync(connection, tableSchema, cancellationToken)

Reads column metadata from a live database.

Register

public static void Register(DbProviderFactory factory)

PostgreSqlDialect.Register(factory)

Registers the PostgreSQL dialect and provider factory with DatabaseProviderRegistry.

factory

The DbProviderFactory for PostgreSQL.

SysNow

public override string SysNow()

result = postgreSqlDialect.SysNow()

System local date/time with offset.

SysUtcNow

public override string SysUtcNow()

result = postgreSqlDialect.SysUtcNow()

System UTC date/time with offset.

UtcNow

public override string UtcNow()

result = postgreSqlDialect.UtcNow()

Current UTC date/time.

Instance

public static readonly PostgreSqlDialect Instance

value = PostgreSqlDialect.Instance

Singleton instance.